CSS – Beginners

CSS is used to control the style of a web document in a simple and easy way.

CSS stands for Cascading Style Sheet.

This tutorial gives complete understanding on CSS.

Before your begin:

Before you begin, it's important that you know Windows or Unix. A working knowledge of Windows or Unix makes it much easier to learn HTML.

You should be familiar with:

· Basic word processing using any text editor.

· How to create directories and files.

· How to navigate through different directories.

· Basic understanding on internet browsing using a browser like Internet Explorer or Firefox etc.

· Basic understanding on developing simple Web Pages using HTML or XHTML.

If you are new to HTML and XHTML then I would suggest you to go through our HTML Tutorial or XHTML Tutorial. Anyone of HTML or XHTML is enough to proceed.

What is CSS?

Cascading Style Sheets, fondly referred to as CSS, is a simple design language intended to simplify the process of making web pages presentable.

CSS handles the look and feel part of a web page. Using CSS, you can control the color of the text, the style of fonts, the spacing between paragraphs, how columns are sized and laid out, what background images or colors are used, as well as a variety of other effects.

CSS is easy to learn and understand but it provides powerful control over the presentation of an HTML document. Most commonly, CSS is combined with the markup languages HTML or XHTML.

Advantages of CSS:

· CSS saves time - You can write CSS once and then reuse same sheet in multiple HTML pages. You can define a style for each HTML element and apply it to as many Web pages as you want.

· Pages load faster - If you are using CSS, you do not need to write HTML tag attributes every time. Just write one CSS rule of a tag and apply to all the occurrences of that tag. So less code means faster download times.

· Easy maintenance - To make a global change, simply change the style, and all elements in all the web pages will be updated automatically.

· Superior styles to HTML - CSS has a much wider array of attributes than HTML so you can give far better look to your HTML page in comparison of HTML attributes.

· Multiple Device Compatibility - Style sheets allow content to be optimized for more than one type of device. By using the same HTML document, different versions of a website can be presented for handheld devices such as PDAs and cell phones or for printing.

· Global web standards - Now HTML attributes are being deprecated and it is being recommended to use CSS. So its a good idea to start using CSS in all the HTML pages to make them compatible to future browsers.

Who Creates and Maintains CSS?

CSS is created and maintained through a group of people within the W3C called the CSS Working Group. The CSS Working Group creates documents called specifications. When a specification has been discussed and officially ratified by W3C members, it becomes a recommendation.

These ratified specifications are called recommendations because the W3C has no control over the actual implementation of the language. Independent companies and organizations create that software.

NOTE: The World Wide Web Consortium, or W3C is a group that makes recommendations about how the Internet works and how it should evolve.

CSS Versions:

Cascading Style Sheets, level 1 (CSS1) was came out of W3C as a recommendation in December 1996. This version describes the CSS language as well as a simple visual formatting model for all the HTML tags.

CSS2 was became a W3C recommendation in May 1998 and builds on CSS1. This version adds support for media-specific style sheets e.g. printers and aural devices, downloadable fonts, element positioning and tables.

css - syntax

A CSS comprises of style rules that are interpreted by the browser and then applied to the corresponding elements in your document. A style rule is made of three parts:

· Selector: A selector is an HTML tag at which style will be applied. This could be any tag like <h1> or <table> etc.

· Property: A property is a type of attribute of HTML tag. Put simply, all the HTML attributes are converted into CSS properties. They could becolor or border etc.

· Value: Values are assigned to properties. For example color property can have value either red or #F1F1F1 etc.

You can put CSS Style Rule Syntax as follows:

selector { property: value }

Example: You can define a table border as follows:

table{ border :1px solid #C00; }

Here table is a selector and border is a property and given value 1px solid #C00 is the value of that property.

You can define selectors in various simple ways based on your comfort. Let me put these selectors one by one.

The Type Selectors:

This is the same selector we have seen above. Again one more example to give a color to all level 1 headings :

h1 {

   color: #36CFFF;

The Universal Selectors:

Rather than selecting elements of a specific type, the universal selector quite simply matches the name of any element type :

* {

  color: #000000;

This rule renders the content of every element in our document in black.

The Descendant Selectors:

Suppose you want to apply a style rule to a particular element only when it lies inside a particular element. As given in the following example, style rule will apply to <em> element only when it lies inside <ul> tag.

ul em {

  color: #000000;

The Class Selectors:

You can define style rules based on the class attribute of the elements. All the elements having that class will be formatted according to the defined rule.

.black {

  color: #000000;

This rule renders the content in black for every element with class attribute set to black in our document. You can make it a bit more particular. For example:

h1.black {

  color: #000000;

This rule renders the content in black for only <h1> elements with class attribute set to black.

You can apply more than one class selectors to given element. Consider the following example :

<p class="center bold">

This para will be styled by the classes center and bold.

</p>

The ID Selectors:

You can define style rules based on the id attribute of the elements. All the elements having that id will be formatted according to the defined rule.

#black {

  color: #000000;

This rule renders the content in black for every element with id attribute set to black in our document. You can make it a bit more particular. For example:

h1#black {

  color: #000000;

This rule renders the content in black for only <h1> elements with id attribute set to black.

The true power of id selectors is when they are used as the foundation for descendant selectors, For example:

#black h2 {

  color: #000000;

In this example all level 2 headings will be displayed in black color only when those headings will lie with in tags having id attribute set toblack.

The Child Selectors:

You have seen descendant selectors. There is one more type of selectors which is very similar to descendants but have different functionality. Consider the following example:

body > p {

  color: #000000;

This rule will render all the paragraphs in black if they are direct child of <body> element. Other paragraphs put inside other elements like <div> or <td> etc. would not have any effect of this rule.

The Attribute Selectors:

You can also apply styles to HTML elements with particular attributes. The style rule below will match all input elements that has a type attribute with a value of text:

input[type="text"]{

  color: #000000;

The advantage to this method is that the <input type="submit" /> element is unaffected, and the color applied only to the desired text fields.

There are following rules applied to attribute selector.

· p[lang] - Selects all paragraph elements with a lang attribute.

· p[lang="fr"] - Selects all paragraph elements whose lang attribute has a value of exactly "fr".

· p[lang~="fr"] - Selects all paragraph elements whose lang attribute contains the word "fr".

· p[lang|="en"] - Selects all paragraph elements whose lang attribute contains values that are exactly "en", or begin with "en-".

Multiple Style Rules:

You may need to define multiple style rules for a single element. You can define these rules to combine multiple properties and corresponding values into a single block as defined in the following example:

h1 {

color: #36C;

font-weight: normal;

letter-spacing: .4em;

margin-bottom: 1em;

text-transform: lowercase;

Here all the property and value pairs are separated by a semi colon (;). You can keep them in a ingle line or multiple lines. For better readability we keep them into separate lines.

For a while don't bother about the properties mentioned in the above block. These properties will be explained in coming chapters and you can find complete detail about properties in CSS References.

Grouping Selectors:

You can apply a style to many selectors if you like. Just separate the selectors with a comma as given in the following example:

h1, h2, h3 {

color: #36C;

font-weight: normal;

letter-spacing: .4em;

margin-bottom: 1em;

text-transform: lowercase;

This define style rule will be applicable to h1, h2 and h3 element as well. The order of the list is irrelevant. All the elements in the selector will have the corresponding declarations applied to them.

You can combine various class selectors together as shown below:

#content, #footer, #supplement {

position: absolute;

left: 510px;

width: 200px;

CSS - Inclusion

There are four ways to associate styles with your HTML document. Most commonly used methods are inline CSS and External CSS.

Embedded CSS - The <style> Element:

You can put your CSS rules into an HTML document using the <style> element. This tag is placed inside <head>...</head> tags. Rules defined using this syntax will be applied to all the elements available in the document. Here is the generic syntax:

<head>

<style type="text/css" media="...">

Style Rules

............

</style>

</head>

Attributes:

Attributes associated with <style> elements are:

Attribute	Value	Description
type	text/css	Specifies the style sheet language as a content-type (MIME type). This is required attribute.
media	screen tty tv projection handheld print braille aural all	Specifies the device the document will be displayed on. Default value is all. This is optional attribute.

Example:

Following is the example of embed CSS based on above syntax:

<head>

<style type="text/css" media="all">

h1{

color: #36C;

</style>

</head>

Inline CSS - The style Attribute:

You can use style attribute of any HTML element to define style rules. These rules will be applied to that element only. Here is the generic syntax:

<element style="...style rules....">

Attributes:

Attribute	Value	Description
style	style rules	The value of style attribute is a combination of style declarations separated by semicolon (;).

Example:

Following is the example of inline CSS based on above syntax:

<h1 style ="color:#36C;"> This is inline CSS </h1>

This will produce following result:

This is inline CSS

External CSS - The <link> Element:

The <link> element can be used to include an external stylesheet file in your HTML document.

An external style sheet is a separate text file with .css extension. You define all the Style rules within this text file and then you can include this file in any HTML document using <link> element.

Here is the generic syntax of including external CSS file:

<head>

<link type="text/css" href="..." media="..." />

</head>

Attributes:

Attributes associated with <style> elements are:

Attribute	Value	Description
type	text/css	Specifies the style sheet language as a content-type (MIME type). This attribute is required.
href	URL	Specifies the style sheet file having Style rules. This attribute is a required.
media	screen tty tv projection handheld print braille aural all	Specifies the device the document will be displayed on. Default value is all. This is optional attribute.

Example:

Consider a simple style sheet file with a name mystyle.css having the following rules:

h1, h2, h3 {

color: #36C;

font-weight: normal;

letter-spacing: .4em;

margin-bottom: 1em;

text-transform: lowercase;

Now you can include this file mystyle.css in any HTML document as follows:

<head>

<link type="text/css" href="mystyle.css" media="all" />

</head>

Imported CSS - @import Rule:

@import is used to import an external stylesheet in a manner similar to the <link> element. Here is the generic syntax of @import rule.

<head>

<@import "URL";

</head>

Here URL is the URL of the style sheet file having style rules. You can use another syntax as well:

<head>

<@import url("URL");

</head>

Example:

Following is the example showing you how to import a style sheet file into HTML document:

<head>

@import "mystyle.css";

</head>

CSS Rules Overriding:

We have discussed four ways to include style sheet rules in a an HTML document. Here is the rule to override any Style Sheet Rule.

· Any inline style sheet takes highest priority. So it will override any rule defined in <style>...</style> tags or rules defined in any external style sheet file.

· Any rule defined in <style>...</style> tags will override rules defined in any external style sheet file.

· Any rule defined in external style sheet file takes lowest priority and rules defined in this file will be applied only when above two rules are not applicable.

Handling old Browsers:

There are still many old browsers who do not support CSS. So we should take care while writing our Embedded CSS in an HTML document. The following snippet shows how you can use comment tags to hide CSS from older browsers:

<style type="text/css">

<!--

body, td {

   color: blue;

-->

</style>

CSS Comments:

Many times you may need to put additional comments in your style sheet blocks. So it is very easy to comment any part in style sheet. You simple put your comments inside /*.....this is a comment in style sheet.....*/.

You can use /* ....*/ to comment multi-line blocks in similar way you do in C and C++ programming languages.

Example:

/* This is an external style sheet file */

h1, h2, h3 {

color: #36C;

font-weight: normal;

letter-spacing: .4em;

margin-bottom: 1em;

text-transform: lowercase;

/* end of style rules. */

css_units

Before we start actual exercise, I would like to give a brief idea about the CSS Measurement Units.

CSS supports a number of measurements including absolute units such as inches, centimeters, points, and so on, as well as relative measures such as percentages and em units. You need these values while specifying various measurements in your Style rules e.gborder="1px solid red".

We have listed out all the CSS Measurement Units alogwith proper Examples:

Unit	Description	Example
%	Defines a measurement as a percentage relative to another value, typically an enclosing element.	p {font-size: 16pt; line-height: 125%;}
cm	Defines a measurement in centimeters.	div {margin-bottom: 2cm;}
em	A relative measurement for the height of a font in em spaces. Because an em unit is equivalent to the size of a given font, if you assign a font to 12pt, each "em" unit would be 12pt; thus, 2em would be 24pt.	p {letter-spacing: 7em;}
ex	This value defines a measurement relative to a font's x-height. The x-height is determined by the height of the font's lowercase letter x.	p {font-size: 24pt; line-height: 3ex;}
in	Defines a measurement in inches.	p {word-spacing: .15in;}
mm	Defines a measurement in millimeters.	p {word-spacing: 15mm;}
pc	Defines a measurement in picas. A pica is equivalent to 12 points; thus, there are 6 picas per inch.	p {font-size: 20pc;}
pt	Defines a measurement in points. A point is defined as 1/72nd of an inch.	body {font-size: 18pt;}
px	Defines a measurement in screen pixels.

css - colors

CSS uses color values to specify a color. Typically, these are used to set a color either for the foreground of an element(i.e., its text) or else for the background of the element. They can also be used to affect the color of borders and other decorative effects.

You can specify your color values in various formats. Following table tells you all possible formats:

Format	Syntax	Example
Hex Code	#RRGGBB	p{color:#FF0000;}
Short Hex Code	#RGB	p{color:#6A7;}
RGB %	rgb(rrr%,ggg%,bbb%)	p{color:rgb(50%,50%,50%);}
RGB Absolute	rgb(rrr,ggg,bbb)	p{color:rgb(0,0,255);}
keyword	aqua, black, etc.	p{color:teal;}

These formats are explained in more detail in the following sections:

CSS Colors - Hex Codes:

A hexadecimal is a 6 digit representation of a color. The first two digits(RR) represent a red value, the next two are a green value(GG), and the last are the blue value(BB).

A hexadecimal value can be taken from any graphics software like Adobe Photoshop, Jasc Paintshop Pro or even using Advanced Paint Brush.

Each hexadecimal code will be preceded by a pound or hash sign #. Following are the examples to use Hexadecimal notation.

Color	Color HEX
	#000000
	#FF0000
	#00FF00
	#0000FF
	#FFFF00
	#00FFFF
	#FF00FF
	#C0C0C0
	#FFFFFF

CSS Colors - Short Hex Codes:

This is a shorter form of the six-digit notation. In this format, each digit is replicated to arrive at an equivalent six-digit value; For example: #6A7 becomes #66AA77.

A hexadecimal value can be taken from any graphics software like Adobe Photoshop, Jasc Paintshop Pro or even using Advanced Paint Brush.

css backgrounds

This tutorial will teach you how to set backgrounds of various HTML elements. You can set following background properties of an element:

· The background-color property is used to set the background color of an element.

· The background-image property is used to set the background image of an element.

· The background-repeat property is used to control the repetition of an image in the background.

· The background-position property is used to control the position of an image in the background.

· The background-attachment property is used to control the scrolling of an image in the background.

· The background property is used as shorthand to specify a number of other background properties.

Set the background color:

Following is the example which demonstrates how to set the background color for an element.

This text has a yellow background color.

</p>

This will produce following result:

This text has a yellow background color.

Set the background image:

Following is the example which demonstrates how to set the background image for an element.

This table has background image set.

</td></tr>

</table>

Repeat the background image:

Following is the example which demonstrates how to repeat the background image if image is small. You can use no-repeat value forbackground-repeat property if you don't want to repeat an image, in this case image will display only once.

By default background-repeat property will have repeat value.

<table style="background-image:url(images/pattern1.gif);

background-repeat: repeat;">

This table has background image which repeats multiple times.

</td></tr>

</table>

Following is the example which demonstrates how to repeat the background image vertically.

<table style="background-image:url(images/pattern1.gif);

background-repeat: repeat-y;">

This table has background image set which will repeat vertically.

</td></tr>

</table>

Following is the example which demonstrates how to repeat the background image horizontally.

<table style="background-image:url(images/pattern1.gif);

background-repeat: repeat-x;">

This table has background image set which will repeat horizontally.

</td></tr>

</table>

Set the background image position:

Following is the example which demonstrates how to set the background image position 100 pixels away from the left side.

<table style="background-image:url(images/pattern1.gif);

background-position:100px;">

Background image positioned 100 pixels away from the left.

</td></tr>

</table>

Following is the example which demonstrates how to set the background image position 100 pixels away from the left side and 200 pixels down from the top.

<table style="background-image:url(images/pattern1.gif);

background-position:100px 200px;">

This table has background image positioned 100

pixels away from the left and 200 pixels from the top.

</td></tr>

</table>

Set the background attachment:

Background attachment determines whether a background image is fixed or scrolls with the rest of the page.

Following is the example which demonstrates how to set the fixed background image.

<p style="background-image:url(images/pattern1.gif);

background-attachment:fixed;">

This parapgraph has fixed background image.

</p>

Following is the example which demonstrates how to set the scrolling background image.

<p style="background-image:url(images/pattern1.gif);

background-attachment:scroll;">

This parapgraph has scrolling background image.

</p>

Shorthand property :

You can use the background property to set all the background properties at once. For example:

This parapgraph has fixed repeated background image.

</p>

css - fonts

This tutorial will teach you how to set fonts of a content available in an HTML element. You can set following font properties of an element:

· The font-family property is used to change the face of a font.

· The font-style property is used to make a font italic or oblique.

· The font-variant property is used to create a small-caps effect.

· The font-weight property is used to increase or decrease how bold or light a font appears.

· The font-size property is used to increase or decrease the size of a font.

· The font property is used as shorthand to specify a number of other font properties.

Set the font family:

Following is the example which demonstrates how to set the font family of an element. Possible value could be any font family name.

<p style="font-family:georgia,garamond,serif;">

This text is rendered in either georgia, garamond, or the default

serif font depending on which font  you have at your system.

</p>

This will produce following result:

This text is rendered in either georgia, garamond, or the default
serif font depending on which font you have at your system.

Set the font style:

Following is the example which demonstrates how to set the font style of an element. Possible values are normal, italic and oblique.

<p style="font-style:italic;">

This text will be rendered in italic style

</p>

This will produce following result:

This text will be rendered in italic style

Set the font variant:

Following is the example which demonstrates how to set the font variant of an element. Possible values are normal and small-caps.

<p style="font-variant:small-caps;">

This text will be rendered as small caps

</p>

This will produce following result:

This text will be renedered as small caps

Set the font weight:

Following is the example which demonstrates how to set the font weight of an element. The font-weight property provides the functionality to specify how bold a font is. Possible values could be normal, bold, bolder, lighter, 100, 200, 300, 400, 500, 600, 700, 800, 900.

<p style="font-weight:bold;">

This font is bold.

</p>

<p style="font-weight:bolder;">

This font is bolder.

</p>

<p style="font-weight:900;">

This font is 900 weight.

</p>

This will produce following result:

This font is bold.

This font is bolder.

This font is 900 weight.

Set the font size:

Following is the example which demonstrates how to set the font size of an element. The font-size property is used to control the size of fonts. Possible values could be xx-small, x-small, small, medium, large, x-large, xx-large, smaller, larger, size in pixels or in %

<p style="font-size:20px;">

This font size is 20 pixels

</p>

<p style="font-size:small;">

This font size is small

</p>

<p style="font-size:large;">

This font size is large

</p>

This will produce following result:

This font size is 20 pixels

This font size is small

This font size is large

Set the font size adjust:

Following is the example which demonstrates how to set the font size adjust of an element. This property enables you to adjust the x-height to make fonts more legible. Possible value could be any number.

<p style="font-size-adjust:0.61;">

This text is using a font-size-adjust value.

</p>

This will produce following result:

This text is using a font-size-adjust value.

Set the font stretch:

Following is the example which demonstrates how to set the font stretch of an element. This property relies on the user's computer to have an expanded or condensed version of the font being used.

Possible values could be normal, wider, narrower, ultra-condensed, extra-condensed, condensed, semi-condensed, semi-expanded, expanded, extra-expanded, ultra-expanded.

<p style="font-stretch:ultra-expanded;">

If this doesn't appear to work, it is likely that

your computer doesn't have a condensed or expanded

version of the font being used.

</p>

This will produce following result:

If this doesn't appear to work, it is likely that your computer doesn't have a condensed or expanded version of the font being used.

Shorthand property :

You can use the font property to set all the font properties at once. For example:

<p style="font:italic small-caps bold 15px georgia;">

Applying all the properties on the text at once.

</p>

This will produce following result:

Applying all the properties on the text at once.

css – text

This tutorial will teach you how to manipulate text using CSS properties. You can set following text properties of an element:

· The color property is used to set the color of a text.

· The direction property is used to set the text direction.

· The letter-spacing property is used to add or subtract space between the letters that make up a word.

· The word-spacing property is used to add or subtract space between the words of a sentence.

· The text-indent property is used to indent the text of a paragraph.

· The text-align property is used to align the text of a document.

· The text-decoration property is used to underline, overline, and strikethrough text.

· The text-transform property is used to capitalize text or convert text to uppercase or lowercase letters.

· The white-space property is used to control the flow and formatting of text.

· The text-shadow property is used to set the text shadow around a text.

Set the text color:

Following is the example which demonstrates how to set the text color. Possible value could be any color name in any valid format.

This text will be written in red.

</p>

This will produce following result:

This text will be written in red.

Set the text direction :

Following is the example which demonstrates how to set the direction of a text. Possible values are ltr or rtl.

This text will be renedered from right to left

</p>

This will produce following result:

This text will be renedered from right to left

Set the space between characters:

Following is the example which demonstrates how to set the space between characters. Possible values are normal or a number specifying space..

This text is having space between letters.

</p>

This will produce following result:

This text is having space between letters.

Set the space between words:

Following is the example which demonstrates how to set the space between words. Possible values are normal or a number specifying space..

This text is having space between words.

</p>

This will produce following result:

This text is having space between words.

Set the text indent:

Following is the example which demonstrates how to indent the first line of a paragraph. Possible values are % or a number specifying indent space..

This text will have first line indented by 1cm

and this line will remain at its actual position

this is done by CSS text-indent property.

</p>

This will produce following result:

This text will have first line indented by 1cm
and this line will remain at its actual position
this is done by CSS text-indent property.

Set the text alignment:

Following is the example which demonstrates how to align a text. Possible values are left, right, center, justify..

This will be right aligned.

</p>

This will be center aligned.

</p>

This will be left aligned.

</p>

This will produce following result:

This will be right aligned.

This will be center aligned.

This will be left aligned.

Decorating the text:

Following is the example which demonstrates how to decorate a text. Possible values are none, underline, overline, line-through, blink..

This will be underlined

</p>

This will be striked through.

</p>

This will have a over line.

</p>

This text will have blinking effect

</p>

This will produce following result:

This will be underlined

~~This will be striked through.~~

This will have a over line.

This text will have blinking effect

Set the text cases:

Following is the example which demonstrates how to set the cases for a text. Possible values are none, capitalize, uppercase, lowercase..

This will be capitalized

</p>

This will be in uppercase

</p>

This will be in lowercase

</p>

This will produce following result:

This Will Be Capitalized

THIS WILL BE IN UPPERCASE

this will be in lowercase

Set the white space between text:

Following is the example which demonstrates how white space inside an element is handled. Possible values are normal, pre, nowrap.

<p style="white-space:pre;">This text has a line break

and the white-space pre setting tells the browser to honor it

just like the HTML pre tag.</p>

This will produce following result:

This text has a line break

and the white-space pre setting tells the browser to honor it

just like the HTML pre tag.

Set the text shadow:

Following is the example which demonstrates how to set the shadow around a text. This may not be supported by all the browsers.

If your browser supports the CSS text-shadow property,

this text will have a blue shadow.</p>

This will produce following result:

If your browser supports the CSS text-shadow property, this text will have a blue shadow.

CSS – images

Images are very important part of any Web Page. Though it is not recommended to include lot of images but it is still important to use good images wherever it is required.

CSS plays a good role to control image display. You can set following image properties using CSS.

· The border property is used to set the width of an image border.

· The height property is used to set the height of an image.

· The width property is used to set the width of an image.

· The -moz-opacity property is used to set the opacity of an image.

The image border Property:

The border property of an image is used to set the width of an image border. This property can have a value in length or in %.

A width of zero pixels means no border.

Here is the example:

<br />

This will produce following result:

The image height Property:

The height property of an image is used to set the height of an image. This property can have a value in length or in %. While giving value in %, it applies it in respect of the box in which an image is available.

Here is the example:

<img style="border:1px solid red; height:100px;"

src="images/logo.gif" />

<br />

<img style="border:1px solid red; height:50%;"

src="images/logo.gif" />

This will produce following result:

The image width Property:

The width property of an image is used to set the width of an image. This property can have a value in length or in %. While giving value in %, it applies it in respect of the box in which an image is available.

Here is the example:

<img style="border:1px solid red; width:100px;"

src="images/logo.gif" />

<br />

<img style="border:1px solid red; width:100%;"

src="images/logo.gif" />

This will produce following result:

The -moz-opacity Property:

The -moz-opacity property of an image is used to set the opacity of an image. This property is used to create a transparent image in Mozilla. IE uses filter:alpha(opacity=x) to create transparent images.

In Mozilla (-moz-opacity:x) x can be a value from 0.0 - 1.0. A lower value makes the element more transparent (The same things goes for the CSS3-valid syntax opacity:x).

In IE (filter:alpha(opacity=x)) x can be a value from 0 - 100. A lower value makes the element more transparent.

Here is the example:

This will produce following result:

CSS – LINK

This tutorial will teach you how to set different properties of a hyper link using CSS. You can set following properties of a hyper link:

We will revisit same properties when we will discuss Pseudo-Classes of CSS.

· The :link Signifies unvisited hyperlinks.

· The :visited Signifies visited hyperlinks.

· The :hover Signifies an element that currently has the user's mouse pointer hovering over it.

· The :active Signifies an element on which the user is currently clicking.

Usually these all properties are kept in the header part of HTML document.

Remember a:hover MUST come after a:link and a:visited in the CSS definition in order to be effective. Also, a:active MUST come after a:hover in the CSS definition as follows.

<style type="text/css">

a:link {color: #000000}

a:visited {color: #006600}

a:hover {color: #FFCC00}

a:active {color: #FF00CC}

</style>

Now we will see how to use these properties to give different effects to hyperlinks.

Set the color of Links:

Following is the example which demonstrates how to set the link color. Possible value could be any color name in any valid format.

<style type="text/css">

a:link {color:#000000}

</style>

<a href="index.html">Black Link</a>

This will produce following black link:

Black Link

Set the color of Visited Links:

Following is the example which demonstrates how to set the color of visited links. Possible value could be any color name in any valid format.

<style type="text/css">

a:visited {color: #006600}

</style>

<a href="index.html">Click this link</a>

This will produce following link. Once you will click this link, it will change its color to green.

Click this link

Change the color of links when mouse is over:

Following is the example which demonstrates how to change the color of links when we bring a mouse pointer over that link. Possible value could be any color name in any valid format.

<style type="text/css">

a:hover {color: #FFCC00}

</style>

<a href="index.html">Bring Mouse Here</a>

This will produce following link. Now you bring your mouse over this link and you will see that it changes its color to yellow.

Bring Mouse Here

Change the color of active links:

Following is the example which demonstrates how to change the color of active links. Possible value could be any color name in any valid format.

<style type="text/css">

a:active {color: #FF00CC}

</style>

<a href="index.html">Click This Link</a>

This will produce following link. This will change it color to pink when user clicks it.

Click This Link

css – tables

This tutorial will teach you how to set different properties of an HTML table using CSS. You can set following properties of a table:

· The border-collapse Specifies whether the browser should control the appearance of adjacent borders that touch each other or whether each cell should maintain its style.

· The border-spacing Specifies the width that should appear between table cells.

· The caption-side Captions are presented in the <caption> element. By default, these are rendered above the table in the document. You use the caption-side property to control the placement of the table caption.

· The empty-cells Specifies whether the border should be shown if a cell is empty.

· The table-layout Allows browsers to speed up layout of a table by using the first width properties it comes across for the rest of a column rather than having to load the whole table before rendering it.

Now we will see how to use these properties with examples.

The border-collapse Property:

This property can have two values collapse and separate. Following is the example to show both values:

<style type="text/css">

table.one {border-collapse:collapse;}

table.two {border-collapse:separate;}

td.a {

      border-style:dotted;

      border-width:3px;

      border-color:#000000;

      padding: 10px;

td.b {border-style:solid;

      border-width:3px;

      border-color:#333333;

      padding:10px;

</style>

<table class="one">

<caption>Collapse Border Example</caption>

<tr><td class="a"> Cell A Collapse Example</td></tr>

<tr><td class="b"> Cell B Collapse Example</td></tr>

</table>

<br />

<table class="two">

<caption>Separate Border Example</caption>

<tr><td class="a"> Cell A Separate Example</td></tr>

<tr><td class="b"> Cell B Separate Example</td></tr>

</table>

This will produce following result:

Collapse Border Example

Cell A Collapse Example

Cell B Collapse Example

Separate Border Example

Cell A Separate Example

Cell B Separate Example

The border-spacing Property:

The border-spacing property specifies the distance that separates adjacent cells. borders. It can take either one or two values; these should be units of length.

If you provide one value it will applies to both vertical and horizontal borders Or you can specify two values, in which case the first refers to the horizontal spacing and the second to the vertical spacing:

NOTE: Unfortunately, this property does not work in Netscape 7 or IE 6.

<style type="text/css">

/* If you provide one value */

table.example {border-spacing:10px;}

/* This is how you can provide two values */

table.example {border-spacing:10px; 15px;}

</style>

Now let's modify previous example and see the effect:

<style type="text/css">

table.one {

   border-collapse:separate;

   width:400px;

   border-spacing:10px;

table.two {

   border-collapse:separate;

   width:400px;

   border-spacing:10px 50px;

</style>

<table class="one" border="1">

<caption>Separate Border Example with border-spacing</caption>

<tr><td> Cell A Collapse Example</td></tr>

<tr><td> Cell B Collapse Example</td></tr>

</table>

<br />

<table class="two" border="1">

<caption>Separate Border Example with border-spacing</caption>

<tr><td> Cell A Separate Example</td></tr>

<tr><td> Cell B Separate Example</td></tr>

</table>

This will produce following result:

Separate Border Example with border-spacing

Cell A Collapse Example

Cell B Collapse Example

Separate Border Example with border-spacing

Cell A Separate Example

Cell B Separate Example

The caption-side Property:

The caption-side property allows you to specify where the content of a <caption> element should be placed in relationship to the table. The table that follows lists the possible values.

This property can have one of the four values top, bottom, left or right. Let us see following example to show each value:

NOTE:These properties may not work with your IE Browser.

<style type="text/css">

caption.top {caption-side:top}

caption.bottom {caption-side:bottom}

caption.left {caption-side:left}

caption.right {caption-side:right}

</style>

<table style="width:400px; border:1px solid black;">

<caption class="top">

This caption will appear at the top

</caption>

<tr><td > Cell A</td></tr>

<tr><td > Cell B</td></tr>

</table>

<br />

<table style="width:400px; border:1px solid black;">

<caption class="bottom">

This caption will appear at the bottom

</caption>

<tr><td > Cell A</td></tr>

<tr><td > Cell B</td></tr>

</table>

<br />

<table style="width:400px; border:1px solid black;">

<caption class="left">

This caption will appear at the left

</caption>

<tr><td > Cell A</td></tr>

<tr><td > Cell B</td></tr>

</table>

<br />

<table style="width:400px; border:1px solid black;">

<caption class="right">

This caption will appear at the right

</caption>

<tr><td > Cell A</td></tr>

<tr><td > Cell B</td></tr>

</table>

This will produce following result:

This caption will appear at the top

Cell A

Cell B

This caption will appear at the bottom

Cell A

Cell B

This caption will appear at the left

Cell A

Cell B

This caption will appear at the right

Cell A

Cell B

The empty-cells Property:

The empty-cells property indicates whether a cell without any content should have a border displayed.

This property can have one of the three values show, hide or inherit.

Here is the empty-cells property used to hide borders of empty cells in the <table> element.

<style type="text/css">

table.empty{

    width:350px;

    border-collapse:separate;

    empty-cells:hide;

td.empty{

    padding:5px;

    border-style:solid;

    border-width:1px;

    border-color:#999999;

</style>

<table class="empty">

<tr>

<th></th>

<th>Title one</th>

<th>Title two</th>

</tr>

<tr>

<th>Row Title</th>

<td class="empty">value</td>

<td class="empty">value</td>

</tr>

<tr>

<th>Row Title</th>

<td class="empty">value</td>

<td class="empty"></td>

</tr>

</table>

This will produce following result:

	Title one	Title two
Row Title	value	value
Row Title	value

The table-layout Property:

The table-layout property is supposed to help you control how a browser should render or lay out a table.

This property can have one of the three values fixed, auto or inherit.

Here is the example to show the difference between these properties.

NOTE:This property is not supported by many browsers so do not rely on this property.

<style type="text/css">

table.auto

table-layout: auto

table.fixed

table-layout: fixed

</style>

<table class="auto" border="1" width="100%">

<tr>

<td width="20%">1000000000000000000000000000</td>

<td width="40%">10000000</td>

<td width="40%">100</td>

</tr>

</table>

<br />

<table class="fixed" border="1" width="100%">

<tr>

<td width="20%">1000000000000000000000000000</td>

<td width="40%">10000000</td>

<td width="40%">100</td>

</tr>

</table>

This will produce following result:

1000000000000000000000000000

10000000

100

1000000000000000000000000000

10000000

100

css –borders

The border properties allow you to specify how the border of the box representing an element should look. There are three properties of a border you can change

· The border-color Specifies the color of a border.

· The border-style Specifies whether a border should be solid, dashed line, double line, or one of the other possible values.

· The border-width Specifies the width of a border.

Now we will see how to use these properties with examples.

The border-color Property:

The border-color property allows you to change the color of the border surrounding an element. You can individually change the color of the bottom, left, top and right sides of an element's border using the properties:

· border-bottom-color changes the color of bottom border.

· border-top-color changes the color of top border.

· border-left-color changes the color of left border.

· border-right-color changes the color of right border.

Here is the example which shows effect of all these properties:

p.example1{

border:1px solid;

border-bottom-color:#009900; /* Green */

border-top-color:#FF0000; /* Red */

border-left-color:#330000; /* Black */

border-right-color:#0000CC; /* Blue */

}

p.example2{

border:1px solid;

border-color:#009900; /* Green */

}

</style>

This example is showing all borders in different colors.

</p>

This example is showing all borders in green color only.

</p>

This will produce following result:

This example is showing all borders in different colors.

This example is showing all borders in green color only.

The border-style Property:

The border-style property allows you to select one of the following styles of border:

· none: No border. (Equivalent of border-width:0;)

· solid: Border is a single solid line.

· dotted: Border is a series of dots.

· dashed: Border is a series of short lines.

· double: Border is two solid lines.

· groove: Border looks as though it is carved into the page.

· ridge: Border looks the opposite of groove.

· inset: Border makes the box look like it is embedded in the page.

· outset: Border makes the box look like it is coming out of the canvas.

· hidden: Same as none, except in terms of border-conflict resolution for table elements.

You can individually change the style of the bottom, left, top, and right borders of an element using following properties:

· border-bottom-style changes the style of bottom border.

· border-top-style changes the style of top border.

· border-left-style changes the style of left border.

· border-right-style changes the style of right border.

Following is the example to show all these border styles:

This is a border with none width.

</p>

This is a solid border.

</p>

This is a dahsed border.

</p>

This is a double border.

</p>

This is a groove border.

</p>

This is aridge border.

</p>

This is a inset border.

</p>

This is a outset border.

</p>

This is a hidden border.

</p>

<p style="border-width:4px;

border-top-style:solid;

border-bottom-style:dashed;

border-left-style:groove;

border-right-style:double;">

This is a a border with four different styles.

</p>

This will produce following result:

This is a border with none width.

This is a solid border.

This is a dahsed border.

This is a double border.

This is a groove border.

This is aridge border.

This is a inset border.

This is a outset border.

This is a hidden border.

This is a a border with four different styles.

The border-width Property:

The border-width property allows you to set the width of an element borders. The value of this property could be either a length in px, pt or cm or it should be set to thin, medium or thick.

You can individually change the width of the bottom, top, left, and right borders of an element using the following properties:

· border-bottom-width changes the width of bottom border.

· border-top-width changes the width of top border.

· border-left-width changes the width of left border.

· border-right-width changes the width of right border.

Following is the example to show all these border width:

This is a solid border whose width is 4px.

</p>

This is a solid border whose width is 4pt.

</p>

This is a solid border whose width is thin.

</p>

This is a solid border whose width is medium;

</p>

This is a solid border whose width is thick.

</p>

<p style="border-bottom-width:4px;

border-top-width:10px;

border-left-width: 2px;

border-right-width:15px;

border-style:solid;">

This is a a border with four different width.

</p>

This will produce following result:

This is a solid border whose width is 4px.

This is a solid border whose width is 4pt.

This is a solid border whose width is thin.

This is a solid border whose width is medium;

This is a solid border whose width is thick.

This is a a border with four different width.

Border Properties Using Shorthand:

The border property allows you to specify color, style, and width of lines in one property:

Following is the example to show to use all the three properties into a single property. This is the most frequently used property to set border around any element.

This example is showing shorthand property for border.

</p>

This will produce following result:

This example is showing shorthand property for border.

css – margins

The margin property defines the space around an HTML element. It is possible to use negative values to overlap content.

The values of the margin property are not inherited by child elements. Remember that the adjacent vertical margins (top and bottom margins) will collapse into each other so that the distance between the blocks is not the sum of the margins, but only the greater of the two margins or the same size as one margin if both are equal.

There are following four properties to set an element margin.

· The margin A shorthand property for setting the margin properties in one declaration.

· The margin-bottom Specifies the bottom margin of an element.

· The margin-top Specifies the top margin of an element.

· The margin-left Specifies the left margin of an element.

· The margin-right Specifies the right margin of an element.

Now we will see how to use these properties with examples.

The margin Property:

The margin property allows you set all of the properties for the four margins in one declaration. Here is the syntax to set margin around a paragraph:

Here is the example:

<p style="margin: 15px; border:1px solid black;">
all four margins will be 15px
</p>

<p style="margin:10px 2%; border:1px solid black;">
top and bottom margin will be 10px, left and right margin will be 2% of the total width of the document.
</p>

<p style="margin: 10px 2% -10px; border:1px solid black;"> top margin will be 10px, left and right margin will be 2% of the total width of the document, bottom margin will be -10px </p>

<p style="margin: 10px 2% -10px auto; border:1px solid black;"> top margin will be 10px, right margin will be 2% of the total width of the document, bottom margin will be -10px, left margin will be set by the browser
</p>

This will produce following result:

all four margins will be 10px

top and bottom margin will be 10px, left and right margin will be 2% of the total width of the document.

top margin will be 10px, left and right margin will be 2% of the total width of the document, bottom margin will be -10px

top margin will be 10px, right margin will be 2% of the total width of the document, bottom margin will be -10px, left margin will be set by the browser

The margin-bottom Property:

The margin-bottom property allows you set bottom margin of an element. It can have a value in length, % or auto.

Here is the example:

<p style="margin-bottom: 15px; border:1px solid black;">
This is a paragraph with a specified bottom margin
</p>

<p style="margin-bottom: 5%; border:1px solid black;">
This is another paragraph with a specified bottom margin in percent
</p>

This will produce following result:

This is a paragraph with a specified bottom margin

This is another paragraph with a specified bottom margin in percent

The margin-top Property:

The margin-top property allows you set top margin of an element. It can have a value in length, % or auto.

Here is the example:

<p style="margin-top: 15px; border:1px solid black;">
This is a paragraph with a specified top margin
</p>

<p style="margin-top: 5%; border:1px solid black;">
This is another paragraph with a specified top margin in percent
</p>

This will produce following result:

This is a paragraph with a specified top margin

This is another paragraph with a specified top margin in percent

The margin-left Property:

The margin-left property allows you set left margin of an element. It can have a value in length, % or auto.

Here is the example:

<p style="margin-left: 15px; border:1px solid black;">
This is a paragraph with a specified left margin
</p>

<p style="margin-left: 5%; border:1px solid black;">
This is another paragraph with a specified top margin in percent
</p>

This will produce following result:

This is a paragraph with a specified left margin

This is another paragraph with a specified top margin in percent

The margin-right Property:

The margin-right property allows you set right margin of an element. It can have a value in length, % or auto.

Here is the example:

<p style="margin-right: 15px; border:1px solid black;">
This is a paragraph with a specified right margin
</p>

<p style="margin-right: 5%; border:1px solid black;">
This is another paragraph with a specified right margin in percent
</p>

This will produce following result:

This is a paragraph with a specified right margin

This is another paragraph with a specified right margin in percent

css – lists

Lists are very helpful in conveying a set of either numbered or bulleted points. This tutorial teaches you how to control list type, position, style etc. using CSS

There are following five CSS properties which can be used to control lists:

· The list-style-type Allows you to control the shape or appearance of the marker.

· The list-style-position Specifies whether a long point that wraps to a second line should align with the first line or start underneath the start of the marker.

· The list-style-image Specifies an image for the marker rather than a bullet point or number.

· The list-style Serves as shorthand for the preceding properties.

· The marker-offset Specifies the distance between a marker and the text in the list.

Now we will see how to use these properties with examples.

The list-style-type Property:

The list-style-type property allows you to control the shape or style of bullet point (also known as a marker) in the case of unordered lists, and the style of numbering characters in ordered lists.

Here are the values which can be used for an unordered list:

Value	Description
none	NA
disc (default)	A filled-in circle
circle	An empty circle
square	A filled-in square

Here are the values which can be used for an ordered list:

Value	Description	Example
decimal	Number	1,2,3,4,5
decimal-leading-zero	0 before the number	01, 02, 03, 04, 05
lower-alpha	Lowercase alphanumeric characters	a, b, c, d, e
upper-alpha	Uppercase alphanumeric characters	A, B, C, D, E
lower-roman	Lowercase Roman numerals	i, ii, iii, iv, v
upper-roman	Uppercase Roman numerals	I, II, III, IV, V
lower-greek	The marker is lower-greek	alpha, beta, gamma
lower-latin	The marker is lower-latin	a, b, c, d, e
upper-latin	The marker is upper-latin	A, B, C, D, E
hebrew	The marker is traditional Hebrew numbering
armenian	The marker is traditional Armenian numbering
georgian	The marker is traditional Georgian numbering
cjk-ideographic	The marker is plain ideographic numbers
hiragana	The marker is hiragana	a, i, u, e, o, ka, ki
katakana	The marker is katakana	A, I, U, E, O, KA, KI
hiragana-iroha	The marker is hiragana-iroha	i, ro, ha, ni, ho, he, to
katakana-iroha	The marker is katakana-iroha	I, RO, HA, NI, HO, HE, TO

Here is the example:

<li>Maths</li>

<li>Social Science</li>

<li>Physics</li>

</ul>

<li>Maths</li>

<li>Social Science</li>

<li>Physics</li>

</ul>

<li>Maths</li>

<li>Social Science</li>

<li>Physics</li>

</ol>

<li>Maths</li>

<li>Social Science</li>

<li>Physics</li>

</ol>

<li>Maths</li>

<li>Social Science</li>

<li>Physics</li>

</ol>

This will produce following result:

o Maths

o Social Science

o Physics

· Maths

· Social Science

· Physics

1. Maths

2. Social Science

3. Physics

a. Maths

b. Social Science

c. Physics

i. Maths

ii. Social Science

iii. Physics

The list-style-position Property:

The list-style-position property indicates whether the marker should appear inside or outside of the box containing the bullet points. It can have one the two values:

Value	Description
none	NA
inside	If the text goes onto a second line, the text will wrap underneath the marker. It will also appear indented to where the text would have started if the list had a value of outside.
outside	If the text goes onto a second line, the text will be aligned with the start of the first line (to the right of the bullet).

Here is the example:

<li>Maths</li>

<li>Social Science</li>

<li>Physics</li>

</ul>

<li>Maths</li>

<li>Social Science</li>

<li>Physics</li>

</ul>

<li>Maths</li>

<li>Social Science</li>

<li>Physics</li>

</ol>

<li>Maths</li>

<li>Social Science</li>

<li>Physics</li>

</ol>

This will produce following result:

o Maths

o Social Science

o Physics

· Maths

· Social Science

· Physics

1. Maths

2. Social Science

3. Physics

a. Maths

b. Social Science

c. Physics

The list-style-image Property:

The list-style-image allows you to specify an image so that you can use your own bullet style. The syntax is as follows, similar to the background-image property with the letters url starting the value of the property followed by the URL in brackets. If it does not find given image then default bullets are used.

Here is the example:

<ul>

<li style="list-style-image: url(images/bullet.gif);">Maths</li>

<li>Social Science</li>

<li>Physics</li>

</ul>

<ol>

<li style="list-style-image: url(images/bullet.gif);">Maths</li>

<li>Social Science</li>

<li>Physics</li>

</ol>

This will produce following result:

· Maths

· Social Science

· Physics

1. Maths

2. Social Science

3. Physics

The list-style Property:

The list-style allows you to specify all the list properties into a single expression. These properties can appear in any order.

Here is the example:

<li>Maths</li>

<li>Social Science</li>

<li>Physics</li>

</ul>

<li>Maths</li>

<li>Social Science</li>

<li>Physics</li>

</ol>

This will produce following result:

§ Maths

§ Social Science

§ Physics

A. Maths

B. Social Science

C. Physics

The marker-offset Property:

The marker-offset property allows you to specify the distance between the marker and the text relating to that marker. Its value should be a length as shown in the following example:

Unfortunately, however, this property is not supported in IE 6 or Netscape 7.

Here is the example:

<li>Maths</li>

<li>Social Science</li>

<li>Physics</li>

</ul>

<li>Maths</li>

<li>Social Science</li>

<li>Physics</li>

</ol>

This will produce following result:

§ Maths

§ Social Science

§ Physics

A. Maths

B. Social Science

C. Physics

css – padding

The padding property allows you to specify how much space should appear between the content of an element and its border:

There are following five CSS properties which can be used to control lists:

The value of this attribute should be either a length, a percentage, or the word inherit. If the value is inherit it will have the same padding as its parent element. If a percentage is used, the percentage is of the containing box.

You can also set different values for the padding on each side of the box using the following properties:

· The padding-bottom Specifies the bottom padding of an element.

· The padding-top Specifies the top padding of an element.

· The padding-left Specifies the left padding of an element.

· The padding-right Specifies the right padding of an element.

· The padding Serves as shorthand for the preceding properties.

Now we will see how to use these properties with examples.

The padding-bottom Property:

The padding-bottom property sets the bottom padding (space) of an element. This can take a value in terms of length of %.

Here is the example:

This is a paragraph with a specified bottom padding

</p>

This is another paragraph with a specified bottom padding in percent

</p>

This will produce following result:

This is a paragraph with a specified bottom padding

This is another paragraph with a specified bottom padding in percent

The padding-top Property:

The padding-top property sets the top padding (space) of an element. This can take a value in terms of length of %.

Here is the example:

This is a paragraph with a specified top padding

</p>

This is another paragraph with a specified top padding in percent

</p>

This will produce following result:

This is a paragraph with a specified top padding

This is another paragraph with a specified top padding in percent

The padding-left Property:

The padding-left property sets the left padding (space) of an element. This can take a value in terms of length of %.

Here is the example:

This is a paragraph with a specified left padding

</p>

This is another paragraph with a specified left padding in percent

</p>

This will produce following result:

This is a paragraph with a specified left padding

This is another paragraph with a specified left padding in percent

The padding-right Property:

The padding-right property sets the right padding (space) of an element. This can take a value in terms of length of %.

Here is the example:

This is a paragraph with a specified right padding

</p>

This is another paragraph with a specified right padding in percent

</p>

This will produce following result:

This is a paragraph with a specified right padding

This is another paragraph with a specified right padding in percent

The padding Property:

The padding property sets the left, right, top and bottom padding (space) of an element. This can take a value in terms of length of %.

Here is the example:

<p style="padding: 15px; border:1px solid black;">
all four padding will be 15px
</p>

<p style="padding:10px 2%; border:1px solid black;">
top and bottom padding will be 10px, left and right padding will be 2% of the total width of the document.
</p>

<p style="padding: 10px 2% 10px; border:1px solid black;"> top padding will be 10px, left and right padding will be 2% of the total width of the document, bottom padding will be 10px </p>

<p style="padding: 10px 2% 10px 10px; border:1px solid black;"> top padding will be 10px, right padding will be 2% of the total width of the document, bottom padding and top padding will be 10px
</p>

This will produce following result:

all four paddings will be 15px

top and bottom paddings will be 10px, left and right paddings will be 2% of the total width of the document.

top padding will be 10px, left and right padding will be 2% of the total width of the document, bottom padding will be 10px

top padding will be 10px, right padding will be 2% of the total width of the document, bottom padding and top padding will be 10px

css - dimension

You have seen the border that surrounds every box ie. element, the padding that can appear inside each box and the margin that can go around them. In this tutorial we will how we can change the dimensions of boxes.

There are following properties that allow you to control the dimensions of a box.

· The height property is used to set the height of a box.

· The width property is used to set the width of a box.

· The line-height property is used to set the height of a line of text.

· The max-height property is used to set a maximum height that a box can be.

· The min-height property is used to set the minimum height that a box can be.

· The max-width property is used to set the maximum width that a box can be.

· The min-width property is used to set the minimum width that a box can be.

The height and width Properties:

The height and width properties allow you to set the height and width for boxes. They can take values of a length, a percentage, or the keyword auto.

Here is the example:

<p style="width:400px; height:100px;border:1px solid red;

             padding:5px; margin:10px;">

This paragraph is 400pixels wide and 100 pixels high

</p>

This will produce following result:

This paragraph is 400pixels wide and 100 pixels high

The line-height Property:

The line-height property allows you to increase the space between lines of text. The value of the line-height property can be a number, a length, or a percentage.

Here is the example:

<p style="width:400px; height:100px;border:1px solid red;

             padding:5px; margin:10px;line-height:30px;">

This paragraph is 400pixels wide and 100 pixels high

and here line height is 30pixels.This paragraph is 400 pixels

wide and 100 pixels high and here line height is 30pixels.

</p>

This will produce following result:

This paragraph is 400pixels wide and 100 pixels high and here line height is 30pixels.This paragraph is 400 pixels wide and 100 pixels high and here line height is 30pixels.

The max-height Property:

The max-height property allows you to specify maximum height of a box. The value of the max-height property can be a number, a length, or a percentage.

NOTE: This property does not work in either Netscape 7 or IE 6.

Here is the example:

<p style="width:400px; max-height:10px;border:1px solid red;

             padding:5px; margin:10px;">

This paragraph is 400px wide and max height is 10px

This paragraph is 400px wide and max height is 10px

This paragraph is 400px wide and max height is 10px

This paragraph is 400px wide and max height is 10px

</p>

<img alt="logo" src="images/css.gif" width="95" height="84" />

This will produce following result:

This paragraph is 400px wide and max height is 10px This paragraph is 400px wide and max height is 10px This paragraph is 400px wide and max height is 10px This paragraph is 400px wide and max height is 10px

The min-height Property:

The min-height property allows you to specify minimum height of a box. The value of the min-height property can be a number, a length, or a percentage.

NOTE: This property does not work in either Netscape 7 or IE 6.

Here is the example:

<p style="width:400px; min-height:200px;border:1px solid red;

             padding:5px; margin:10px;">

This paragraph is 400px wide and min height is 200px

This paragraph is 400px wide and min height is 200px

This paragraph is 400px wide and min height is 200px

This paragraph is 400px wide and min height is 200px

</p>

<img alt="logo" src="images/css.gif" width="95" height="84" />

This will produce following result:

This paragraph is 400px wide and min height is 200px This paragraph is 400px wide and min height is 200px This paragraph is 400px wide and min height is 200px This paragraph is 400px wide and min height is 200px

The max-width Property:

The max-width property allows you to specify maximum width of a box. The value of the max-width property can be a number, a length, or a percentage.

NOTE: This property does not work in either Netscape 7 or IE 6.

Here is the example:

<p style="max-width:100px; height:200px;border:1px solid red;

             padding:5px; margin:10px;">

This paragraph is 200px high and max width is 100px

This paragraph is 200px high and max width is 100px

This paragraph is 200px high and max width is 100px

This paragraph is 200px high and max width is 100px

This paragraph is 200px high and max width is 100px

</p>

<img alt="logo" src="images/css.gif" width="95" height="84" />

This will produce following result:

This paragraph is 200px high and max width is 100px This paragraph is 200px high and max width is 100px This paragraph is 200px high and max width is 100px This paragraph is 200px high and max width is 100px This paragraph is 200px high and max width is 100px

The min-width Property:

The min-width property allows you to specify minimum width of a box. The value of the min-width property can be a number, a length, or a percentage.

NOTE: This property does not work in either Netscape 7 or IE 6.

Here is the example:

<p style="min-width:400px; height:100px;border:1px solid red;

             padding:5px; margin:10px;">

This paragraph is 100px high and min width is 400px

This paragraph is 100px high and min width is 400px

This paragraph is 100px high and min width is 400px

This paragraph is 100px high and min width is 400px

This paragraph is 100px high and min width is 400px

</p>

<img alt="logo" src="images/css.gif" width="95" height="84" />

This will produce following result:

This paragraph is 100px high and min width is 400px This paragraph is 100px high and min width is 400px This paragraph is 100px high and min width is 400px This paragraph is 100px high and min width is 400px This paragraph is 100px high and min width is 400px

css - scrollbars

There may be a case when an element's content might be larger than the amount of space allocated to it. For example given width and height properties did not allow enough room to accommodate the content of the element.

CSS provides a property called overflow which tells the browser what to do if the box's contents is larger than the box itself. This property can take one of the following values:

Value	Description
visible	Allows the content to overflow the borders of its containing element.
hidden	The content of the nested element is simply cut off at the border of the containing element and no scrollbars is visible.
scroll	The size of the containing element does not change, but the scrollbars are added to allow the user to scroll to see the content.
auto	The purpose is the same as scroll, but the scrollbar will be shown only if the content does overflow.

Here is the example:

<style type="text/css">

.scroll{

       display:block;

       border: 1px solid red;

       padding:5px;

       margin-top:5px;

       width:300px;

       height:50px;

       overflow:scroll;

.auto{

       display:block;

       border: 1px solid red;

       padding:5px;

       margin-top:5px;

       width:300px;

       height:50px;

       overflow:auto;

</style>

<p>Example of scroll value:</p>

<div class="scroll">

I am going to keep lot of content here just to show

you how scrollbars works if there is an overflow in

an element box. This provides your horizontal as well

 as vertical scrollbars.

</div>

<br />

<p>Example of auto value:</p>

<div class="auto">

I am going to keep lot of content here just to show

you how scrollbars works if there is an overflow in

an element box. This provides your horizontal as well

as vertical scrollbars.

</div>

This will produce following result:

Example of scroll value:

I am going to keep lot of content here just to show you how scrollbars works if there is an overflow in an element box. This provides your horizontal as well as vertical scrollbars.

Example of auto value:

I am going to keep lot of content here just to show you how scrollbars works if there is an overflow in an element box. This provides your horizontal as well as vertical scrollbars.

Basic CSS Implementation and Positioning

This article is designed to be a starting point for basic CSS concepts and I hope many will find it useful. The topics we will cover here are answers to questions I get every day on the forum and I felt whipping up a comprehensive guide of CSS fundamentals could benefit our members. Along the way, I've included some helpful links and various tips and tricks that might come in handy for anyone looking to learn more about CSS.

Example Files

I've put together a set of example files for the exercises here. They include all the HTML and CSS files for the examples. There is also a blank HTML file linked to a blank CSS file, if you would like to follow along as we go. You can download them here.

This article covers a lot of ground, we'll go over the basics first. If you're familiar with the basics, feel free to jump ahead to the positioning examples:

§ Floats and Clears basics

§ Using Floats to Create a Horizontal Menu

§ CSS Positioning Properties

§ Using Relative and Absolute positioning

Why CSS is Important

Basically, anything related to the look of an element on a web page is controlled via CSS. CSS is attached to HTML elements and is used to control what HTML elements look like - how big or small, how it is spaced, where it appears, what color it is, ECT. This is necessary as HTML by itself doesn't offer many options in terms of looks, positioning, or style for that matter. It basically goes up and down, side to side and isn't very exciting in it's raw form. A primary purpose of HTML is to present content, and CSS exists purely to style that content.

Implementing styles

In order to use CSS, styles must be applied to HTML elements. The most preferable way is to add CSS to a style sheet also known as a css file. Our templates, and pretty much every template out there, come with a number of style sheets built in that you can access and modify to suit your needs. If you're using Gantry, check out this article I wrote a few months back, it covers adding a custom style sheet to a Gantry template.

If you're on Joomla and feeling adventurous, check out Andy Miller's article on building a CSS plugin, or you can just download it and use it as well. This allows you to place custom CSS directly in your articles.

More reference on inserting CSS - Three Ways to Insert CSS

If you would like to try the examples without too much effort, feel free to use the blank.html and blank.css files in the example files. They are linked together so you can use them right away.You can download them here.

The other way of applying styles, is using inline styles directly inside of your HTML tags. We'll go over why this is method is frowned upon.

Inline Styles

An inline style is where you use the style attribute in your HTML to define css properties. While inline styles can offer an easy and quick solution, they can be difficult to update later and they can interfere with other style sheets that may be in use. For example, take this inline style that creates a box:

This is my box

This approach can work in some cases, but it's best to stay away from this method if possible. For example, say you're working on a website that has 200 articles in Joomla, and each one needs this box. Later you decide the backgound should be green. Now you'll need to go into each article and update the style individually for each one. This would become a very time consuming process that would leave a lot of room for error.

Unfortunately, these types of styles are commonly generated by WYSIWYG (What You See Is What You Get) or Visual editors that are used to input content in CMS programs. They are often added to your content unknowingly and can be the cause of formatting inconsistencies between template styles and content styles. What you see may be what you get - but it's not always what you want. In many cases, you can't see all the extra code that is added in, and these problems can usually be corrected by looking at the code and stripping out the inline styles.

Also in this months Magazine, Rocket Theme Moderator David Goode has put together an article addressing these types of issues in content editors. Take a look here, it covers some things to look out for and ways to input identifiers. Which we will go over next.

Element Identifiers

Since we now know that using the style attribute in our HTML is frowned upon, we'll discuss the alternative. The better solution is to use either the id or class attributes in our HTML to create an element identifier. This is used to identify a single HTML element (id), or group of elements (class), by a specific name of your choosing. This name can then be used in the style sheet to apply CSS properties. Then, the elements identified by that name in the HTML will have those styles applied to them. We'll go over how that works.

We'll go back to the box example to show how this works. Instead of using an inline style, I'll use the class attribute to give the box a class name of my-box:

Notice how the code is much simpler to work with. Of course, it will not do much for us until we add in the CSS into the style sheet. We'll do that now. Add the styles for the box to your style sheet by using the class name identifier, like so:

1..my-box
{width:150px;

height:150px; margin:0 auto; border:1px blacksolid; background:#ddd; text-align:center;}

You may notice there is a dot, or period, before the name in the CSS. This is called a selector, specifically a class selector in this case. To use the class name, place the dot with the name immediately following it. Id selectors use the # hashmark before the name. Then any CSS properties you add will go inside the curly braces. We won't go too deep into CSS syntax here, you can check out this link for some basics - CSS Syntax.

A few important points do apply here:

§ The names you use must be unique and they must exactly match in both the HTML and CSS to work.

§ An element that uses an ID can only appear once on a page, otherwise causing an HTML validation error. For that reason, ID's are used for primarily for grouping, or identifying, specific parts of your site - header, sidebar, footer for example.

§ Classes can be used as many times as you like and applied to different types of elements freely. For this reason, they are often used for content elements and other repeatable elements on your page.

For the purposes of this article we'll deal mostly with classes. Unless you have a specific need to use an id, using a class name will work just fine.

There are some distinct advantages to working this way. Think about the previous example of using the box div in 200 separate articles. If we used the class name and style sheet, instead of the inline style, and we needed to change the style of all the elements later, we just need to edit one line of CSS code. All of the elements using the my-box class name will be updated in one shot. By taking an extra step at the beginning, you can save hours of time later.

There is a lot more to CSS selectors than what we have covered here, if you'd like to see what else is possible, this is a handy link from the w3schools.com website, CSS Selector Reference. This website offers a simple and comprehensive guide to CSS properties, so poke around a bit if you want to learn more.

For now, we'll move on and take a look at a few simple ways of using CSS in our content to overcome some common situations and challenges.

CSS Positioning

Positioning is one of the most powerful, yet often misunderstood, aspects of CSS. While it can be used to create complex layouts, like the Gantry Framework for example, we'll just cover the basics and show how it can be used in a content type setting.

Floats and Clears

Floats are a useful way to position elements to the left or right side. When an element has a float applied, it basically gets out of the way and all of the nearby non-floated elements will flow around it, similar to wrapping text around an image in a word processor or a newspaper. Floats are fairly easy to implement, but they also come with their own set of challenges, we'll address those as we go. Feel free to reference css-floats.html and css-floats.css in the example files, all of the code for these examples can be found there.

Floats

For example, this could be a common layout issue for an article or post that appears on a website using a CMS program. You have an image and a paragraph of text inside an article. The article itself is a div, generated through the template or framework, and the content from the editor appears inside. Without using floats or additional CSS, the image will appear above the text in this case, as this is how HTML handles these elements by default.

Lorem ipsum dolor sit amet, consectetur adipiscing elit. Donec quis varius libero. Mauris sem elit, laoreet vel porttitor nec, rhoncus quis eros. Duis quis euismod ipsum. Vestibulum iaculis mi tincidunt leo semper egestas.

As we can see, this isn't the most visually appealing layout. It would make more sense to have the text occupying the space next to the image, instead of sitting below it. Using a float, that is exactly what we'll do. A float takes an element out of the default flow of HTML, so the paragraph text will move up to wrap around the image.

First, we'll create two new class styles in the CSS that use the left and right float properties. While you can choose any names you like for the classes, it can be helpful to use names that make sense and are easy to remember. Be sure to use the dot before the name to designate it as a class selector, like so:

1..float-left{ float:left;}

2..float-right{ float:right;}

Now that we have defined our classes in the CSS, we'll add one of them to the HTML class attribute inside the image tag, depending on which way you want it to float. In this example, we'll go left. Since we have set up class names for both left and right floats, it's easy to change your mind or experiment simply by updating the class attribute in the HTML.

We can see the result might not be what was expected. The purpose of this example is to show both the power and pitfalls of applying a float. As you can see, this moved the image to left and allowed the text to flow into the horizontal space the image was occupying previously, which was the intended goal. We've solved one problem, but simultaneously created another.

Since the floated image has been taken out of the normal flow, it is no longer affecting the height of the containing div. The height of the div is not defined, so the div height is determined by the height of the content inside of the div, and we would like for it to stay that way. This is so it will remain flexible should we choose to add or remove additional content later - that's why defining a fixed height for the div itself wouldn't be a good solution. In this case, the div has condensed around the paragraph text, creating an overlap of the image and the bottom of the container. If the text was longer this might not be as much of an issue, but in this case, I intentionally used a short snippet of text to illustrate this example. Thankfully, there is a simple solution.

Clearing

This brings us to clearing. A clear is used to get around, or cancel a float. It basically bypasses a floated element and restores the normal flow. Clears, like floats, can be applied to the left or right. They can also be applied to both sides - which usually does the trick in most situations.

In our example, we wish to preserve the normal height of our containing div, so we need to create a clear below our content so the float doesn't affect the container. To create a clearing element, add this to your style sheet:

1..clear
{clear:both;}

Then we'll add a clearing div in the HTML under our content, but inside the containing div, that uses the "clear" class name, like so:

And we can see the result here

Using an empty div to clear is a standard technique. It has no height unless you specify otherwise or put content inside it, thus remaining invisible. In this case, it was specifically created for the purpose of clearing the float. It restores the flow and eliminates the bunched up container issue nicely.

Finishing Touches

Now that we have the layout of our content working, let's take a look at the content inside. One issue is that the paragraph text is pushed up against the image. We can fix that easily by applying a margin to the image in the CSS. Since we are already using a class for the image to apply the float, we could easily add our margin to that same class in the style sheet to make the adjustment. Since we're learning some tricks, we'll instead create a new class that will be specific to the images in the article content. This is a good practice, particularly if you plan to use, or are currently using, the original float classes in other places. In real life, if you happened to be using that class elsewhere, any changes made to it would affect all the elements using it, which may not be a desired effect.

By using a new class name, we can fix this specific spacing issue, without affecting anything else, and add additional styles to spruce up the look of the content as well. In the style sheet, we'll create a new identifier class called "article-img". Add this to the style sheet:

1..article-img
{float:left;

margin-right: 10px; border:1px black solid;padding: 2px; background:#666; }

In your HTML, be sure to update the image class attribute to use the new identifier:

We see the final result. The right margin we applied to the image pushed the paragraph to the right a bit, fixing the spacing issue. I also added a border, a background color and a bit of padding to create a framing effect, giving the image a bit more pop. Feel free to add more styles and experiment with the look if you like, there is certainly more that could be done.

Now that you have your image class identifier and style worked out, you can use that class name in all of the images in similar articles and achieve the same result with minimal effort. Should a unique layout circumstance come up, you can simply create a new identifier, change the style to suit your needs and update the HTML class attribute accordingly. Once the identifiers and HTML are in place, you'll be able to easily experiment with various styles and CSS properties. All the changes will happen directly in the style sheet and the only real limit is your creativity.

Using Floats to Create a Horizontal Menu

Let's take a quick look at a more advanced use for a float. One of the most common questions on the forum is about making vertical menus horizontal. Since Joomla moved on from version 1.5, the horizontal menu is no longer an option in the default menu module, much to the dismay of many. Fortunately, it's an easy task to accomplish by using a float. The only real difference between a vertical menu and a horizontal menu is that the list items inside use a float.

Take this for example, this is a basic HTML list, most menus are made from HTML list elements. This is a stripped down version of what the structure for a Joomla menu looks like.

1.<ul
class="menu">

2.<li>Menu Item
one</li>

3.<li>Menu Item
two</li>

4.<li>Menu Item
three</li>

5.<li>Menu Item
four</li>

6.</ul>

With no styling, it looks like this:

§ Menu Item one

§ Menu Item two

§ Menu Item three

§ Menu Item four

Using Descendant Selectors

You can see the ul (unordered list) element uses the "menu" class as an identifier (as all default menus in Joomla do), and there are li's (list items) inside with our menu contents. To accomplish our goal, we need to apply a float to the list items inside the ul element. The list items themselves do not have identifiers, but they are inside of the ul element which does have a class name identifier. We can use that class name to apply styles to the content inside. Remember, the "C" in CSS stands for Cascading, part of the cascading concept is descendant selecting. Basically, an element that contains other elements is considered a parent, and the elements inside are children, or descendants, of the parent element. In this case, the ul is the parent, and the li's are the children. By using a descendant selector we can target the list items specifically. This is actually easier than it sounds, the CSS would look like this:

1..menu li{float: left; margin:0 10px;}

We have used the menu class name in the same way as before, but by adding a single space and the name of the child element afterward, we have created a descendant selector. Meaning the styles are specifically applied to all of the list items inside the menu class. In this case, we have floated the list items left, and added some margins on the side to create space between them. One simple line of CSS will do the trick, it just has to be applied in the right way. Below, you can see the result.

· Menu Item one

· Menu Item two

· Menu Item three

· Menu Item four

To take the concept one step further, if you applied that code to your site and you were using more than one menu, the change would be applied to all menus with the class name of "menu". That could be a problem, especially if you had another menu that needs to stay vertical. Using descendant selectors again is the answer, there is no limit on how many levels of descendance you can use, you just need to identify a parent element of the menu you wish to change. For the sake of argument we'll say the menu you want to change is in the footer position of a Rocket Theme template. All the primary module / widget positions in Gantry are divs with ID's, so you can use those ID's to target the modules inside. For example:

1.#rt-footer .menu
li{float:

left; margin:0 10px;}

Now you are only applying the style to all the list items inside the menu class that are inside the rt-footer element - any menu list items not inside of rt-footer will be unaffected. You could get more specific in Joomla by adding a module class suffix in your module settings and using that as an identifier, thus applying the style only to a specific module, like:

1..module-class-suffix
.menu li{float:

left; margin:0 10px;}

Understanding how to single out the elements you wish to change is a huge key to success in CSS. Being handy with Firebug or a Web Inspector will serve you well, as looking at the source code is often the easiest way to determine the name identifiers of elements and the parent elements they are inside. Once you have that information, jotting down a line of properly targeted CSS in your style sheet will make the specific changes you need, where you need them, and nowhere else.

CSS Positioning Properties

Understanding the how positioning properties work in CSS can be challenging at first, somewhat due to the terminology and the context of how elements are positioned within each other, and in some cases, within your browser window. While it can be a bit confusing at first, the power that comes with understanding them will give you complete control over the placement of your elements and allow you to create more depth in your designs.

There are four position properties in CSS. By default, all elements use Static Positioning. There really isn't much to understand with this one, it doesn't need to be defined anywhere and it's pretty much what you are seeing on the screen already. Static positioned elements follow the normal flow of HTML, that's really all there is to know about it. This is the only positioning property that cannot be moved with the top, right, bottom, left properties or have z-index applied to it, only the other three can make use these properies, we'll cover all that in a bit.

Fixed Positioning

The next property, Fixed Positioning, is not used a whole lot, but it can accomplish a few specific tasks. Elements that use fixed positioning are taken out of the normal flow and positioned relative to the browser window. The element is then "fixed" in that position within your window, regardless of page scrolling, it just sticks in that spot permanently. This makes it a less than ideal solution for basic positioning tasks, as everyone has a different monitor size, browser window size ECT. The results can be inconsistent from one computer to the next, and changing the size of the browser window can move the element as well.

The power of fixed positioning is usually put to work when trying to create a fixed header, a fixed footer, or on annoying websites that place an ad on the screen that stays in a fixed location regardless of the page being scrolled up or down. Most of the time it's in a vertical setting, placed at the very top or very bottom. For example, you have a footer you wish to stay at the bottom of the page at all times. Fixed Positioning is the right tool for the job.

Due to the way it works, it's difficult to place an example here, as it would be stuck on the page we are seeing right now. A good reference is our Zephyr Theme, take a look here: Zephyr Theme. Notice the fixed footer at the bottom, it stays there even when you scroll down or resize the browser window. This is fixed positioning in action, the CSS that makes this happen is this:

1..fixedfooter-1 #rt-footerbar {

2.position: fixed;

3.width: 100%;

4.bottom: 0;

5.left: 0;

6.z-index: 1000;

7.}

The position is set to fixed, then it is positioned by the left and bottom properties. Since bottom is set to zero, it is placed directly at the very bottom of the browser window, that is the notable property in this case. You may also notice the z-index property, which is used to stack positioned elements. The high z-index number ensures it stays on top and isn't covered by other elements, more on this later. Of course, in this example, there is more happening behind the scenes, as the fixedfooter-1 element is generated via Javascript and controlled by template parameters, but it serves to illustrate the point. Besides this type of application, there aren't many other practical uses for fixed positioning.

Relative Positioning

This is possibly the most confusing of the positioning properties for beginners, but understanding how it works is critical when using CSS to precisely position elements. The term "relative" is what throws most folks off, it implies that the element is positioned relatively to something else. This is not the case. In fact, adding position:relative; to an element doesn't change the position of the element at all. The real power of relative positioning is slightly counter-intuitive at first. When applied, it transforms the element into a positioning context that can be used as a reference point to position other elements.

Positioning Context

Basically, by applying position relative to an element, you're not changing the position of that element. Instead, you have made it the relative position, or positioning context, that other elements can then use as a basis for their positioning. This comes in handy when working with elements that use absolute positioning. Relative and absolute positioning go hand in hand. Often, trying to use absolute positioning without the context of a relatively positioned element can be messy and produce unexpected results. As I mentioned, this can be a bit confusing until you see it in action, we'll get to an example soon.

Absolute Positioning

Absolute positioning is similar to fixed positioning in that absolutely positioned elements are completely removed from the flow of the HTML. The main difference between them is the positioning context. While fixed position elements use the browser window as a positioning context, absolutely positioned elements use relative positioned elements as their positioning context. In the case that there are no relatively positioned elements available, it uses the roothtml element as it's context. The notable point here is that the positioning context is attached to the html elements, and the context can be set anywhere on the page by using position relative, this makes it infinitely more useful than fixed positioning. By using absolute positioning inside of a relatively positioned element you can make precise positioning adjustments to place your elements anywhere you like.

Positioning in Action

In this simple example we'll go over how all of this actually works together. Feel free to open the css-positioning.html and css-positioning.css files in the examples files to follow along. Or jump to css-positioning-final.html and css-positioning-final.css files to see the end results.

This is the Header

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Here, we have two divs, one inside the other. The outer div will simulate an HTML page, as with some of the CSS we are about to do here might have some unwanted effects on this actual webpage. Basically, it just has some dimensions and position:relative; applied to it from the start. Here is the HTML.

As you see, there are two divs both with unique class names. The inner div contains content, a h2 header, 2 images and a paragraph, each with unique class names as well. I've done this to create a way to position each element individually through the CSS. The base CSS looks like this:

01./* Positioning
Example */

02.

03..positioning-container{position:relative;

04.width:575px; margin:0 auto; border:1px black solid; padding:50px;background:#eee;}

05.

06..inner-container{border:1px black solid; background:#fff;padding:10px;}

07.

08..demo-header{padding:20px; color:#fff; background: gray; border:1pxblack solid; width:200px; margin-top:0;

09.-moz-box-shadow: 5px 5px 5px rgba(0,0,0,0.5);

10.-webkit-box-shadow: 5px 5px 5px rgba(0,0,0,0.5);

11.box-shadow: 5px 5px 5px rgba(0,0,0,0.5);}

12.

13..inner-container
img{border:1px

black solid;

14.-moz-box-shadow: 5px 5px 5px rgba(0,0,0,0.5);

15.-webkit-box-shadow: 5px 5px 5px rgba(0,0,0,0.5);

16.box-shadow: 5px 5px 5px rgba(0,0,0,0.5);}

17.

18..sample-image-01{}

19..sample-image-02{}

20.

21..sample-content{}

Since we have our classes set up in both the HTML and the CSS, making changes from here will only require editing the style sheet. Some of the content elements have some styles, and others haven't been styled yet, but we'll fill them in as we go. Notice that I used a descendant selector to add a border and CSS3 box shadow to the both the images in the inner container in one shot, instead of using the same CSS properties twice inside the two individual identifiers, this works well if you want the all the elements of a certain type to share properties. We'll do more with that in a minute. Lets get to the positioning.

We'll start with exploring how relative positioning works by applying absolute positioning to the h2 demo-header. In the CSS, add position:absolute; with top and left positions of 0 to the demo-header class:

1..demo-header { position:absolute; top:0; left:0;

2.padding:20px; color:#fff; background: gray; border:1px black solid;width:200px; margin-top:0;}

This is the Header

Basically, we have removed the element from the HTML flow, and positioned it at the very top left of the positioning context, which is the outer div that has position:relative applied to it. Even though the element is inside the inner div, the outer div is the positioning context that the absolute positioning will use. If we didn't have an outer div with position:relative, the header would be at the very top left of the web page, which would not be preferable in most cases.

To illustrate this point further, in the CSS for the inner-container, add position:relative;

1..inner-container{ position: relative;

2.border:1px black solid; background:#fff; padding:10px;}

This is the Header

Now the header is positioned at the top left of the inner div, as we have changed the positioning context by adding position relative to that element. Absolutely positioned elements will use the closest relatively positioned element as their home base so to speak.

Hopefully, the relative positioning concept is starting to make sense at this point. Now that we have our defined our positioning context as the inner-container div, we can use the positioning properties in the absolutely positioned element to be a bit more creative with our layout. The top, left, bottom, right values set the coordinates in pixels for the distance from that particular side. A common use of absolute positioning is to break elements "outside the box" so to speak, creating a three dimensional effect. This can be done by using negative values in the positioning properties, update your CSS like so:

1..demo-header { position:absolute; top:-25px; left:-25px;

2.padding:20px; color:#fff; background: gray; border:1px black solid;width:200px; margin-top:0;

3.}

This is the Header

This adds a bit of dimension to the page and makes the header pop out a bit. The CSS3 box shadow helps this effect come to life. CSS is powerful and offers many options, don't be afraid to get creative with it.

Now that we have a nicely positioned header, we can move on to the images. Just to illustrate some different ways of using the positioning, lets stack them on the right side. Remember the descendant selector we used to create the borders - we'll add position:absolute; to that to apply the property to both images in one shot, then input different coordinates in the individual classes to place them in different locations. Update the CSS for the images like so:

1..inner-container
img{

position:absolute;

2.border:1px black solid;

3.-moz-box-shadow: 5px 5px 5px rgba(0,0,0,0.5);

4.-webkit-box-shadow: 5px 5px 5px rgba(0,0,0,0.5);

5.box-shadow: 5px 5px 5px rgba(0,0,0,0.5);}

6.

7..sample-image-01{ top: 10px; right:10px;}

8..sample-image-02{ bottom: 10px; right:10px;}

Remember that when we position elements absolutely, it removes them from the flow, almost as if they didn't exist at all. In this case, our inner div will collapse when the images have the positioning applied. Previously, we used a clear to fix this, but in this case we aren't using a float so that won't work. This time, we'll define a height for the inner div to reserve the space and contain the images inside the box. The images here are 150px tall, so around 300px will do the trick. In this case, I'll make it a bit smaller so we can experiment with z-index, as the images will slightly overlap. Update the CSS for the inner-container:

1..inner-container{ position: relative; height:275px;

2.border:1px black solid; background:#fff; padding:10px;}

This is the Header

Now the images are on the right, 10px in from each side, and the bottom image is covering the top image. Let's switch this so the top image covers the bottom image by using z-index. We'll also stagger the right positioning by 5px in opposite directions on each image, just to mix it up a bit. Once again update the CSS for the image classes:

1..sample-image-01{ top: 10px; right:15px; z-index:10;}

2..sample-image-02{ bottom: 10px; right:5px; z-index: 1;}

This is the Header

By assigning image-01 a higher z-index value than image-02, we have placed it in the front. The z-index property is fairly simple to understand. To use z-index, an element must first have a positioning property applied to it - other than static of course. Then the stacking order is determined by the z-index number, higher numbers appear in the front, lower numbers appear in the back. This can be handy to know should you come across a situation where an element on your page is "on top" of something it shouldn't be.

Finally, we'll fit our paragraph text in there so we can actually read it. Since everything else has been moved out of the flow, portions of it are covered up, which isn't ideal for a content setting. At this point we don't need to do anything too crazy, we just need to get it to fit in the space that is left. We can apply a margins to the paragraph to accomplish this. In this particular instance, absolute positioning might not be the best way to go. While it is a powerful tool, be careful not to overuse it or otherwise abuse it. Margins in themselves are a powerful positioning tool as well. For now, update the sample-content class, like so:

1..sample-content{ margin: 75px 200px 0 25px;}

This is the Header

Here we've added margins in a shorthand fashion - the order goes top, right, bottom, left - clockwise from the top is the easy way to remember. We've pushed it down 75px from the top, pushed it in from the right 200px - to get past the width of the images, the bottom doesn't really matter in this case, and 25px in from the left just for some space.

While this is a pretty basic example, it illustrates the basic concepts of positioning. What we're left with is a bit more stylish than what we started with, and it's easy to see how complex design ideas can become reality on a web page with a just small bit of CSS. Understanding how it works is the key to success.

By using element identifiers (class names) in our HTML from the start, we were able to transform the content purely using CSS. Once the original HTML was put in place, it didn't need to be updated throughout the course of the example. The benefits of this method include saving time, lighter code, and more styling flexibility.

The Bottom Line

We've covered a ground lot here, but these basic concepts really only scratch the surface of what can be done with CSS positioning, or CSS in general. Hopefully, the information here provided a fundamental grasp on using HTML and CSS together and a general understanding of positioning concepts in CSS. Really, we didn't use too much code in any of the examples and I hope you've seen how easy it is to address general layout and spacing issues with just a touch of code applied in the right place.

While I took care to include as much detail as possible, there is much we couldn't cover in this single article. There are plenty of resources and tutorials online and lots of great books on the topic. The great thing about knowing CSS is that no matter whether you're using Joomla, Wordpress, Drupal, or something else - CSS is CSS, and everything that is web based uses it. The knowledge can be applied to any framework, or any situation. It's all about understanding how it works, from there your creativity is the only limit.

Getting Started with CSS: A Practical Exercise

http://line25.com/tutorials/getting-started-with-css-a-practical-exercise

Learning how to write CSS is an essential lesson in any web design classroom. For you who are just starting out, here’s a beginner’s guide to help you learn the basics in proper CSS execution.

Preface

Performing even the most basic CSS task requires an eye for details. Code is poetry and not something for the restless. In this beginner’s guide tutorial we will show an example of how to create an html web page using div tag markup and later defining them in an external stylesheet.

Step 1 – The Markup and Use of Tags

The HTML markup comes first and you should always leave page styling (CSS) until the markup is completely finished.

HTML stands for Hypertext Mark-up Language and is the means to describe the structure of text-based information of a web page. Before you learn how to apply styling through CSS you will have to also learn how to apply the elements of structure.

When doing a markup you use “tags” that are surrounded by angle brackets. Tags are used so that you may define what you want on the web page. The CSS is later applied to define where the content of each tag should appear in the web browser window, and how it should look.

Elementary tags in web page are:

<html>

<head>

        <title></title>

</head>

        <body>

        </body>

</html>

It is within the <body> tag you then use more tags to markup web page element and content.

A very important tag that is used to divide and define structure is the <div>. Using this tag you may divide your web page into boxes. Within a div tag you can then add more tags to define its content (links, text, images etc.), later to be styled in the CSS.

Use an image editor (Photoshop recommended) to draw a markup the boxes:

In code, this web page markup would look like below, as an example on how to use div tags:

<html>

<head>

        <title></title>

</head>

<body>

        <div id="wrapper">

               <div id="header">

               </div><!--Header-->

               <div id="navigation">

               </div><!--Navigation-->

               <div id="menu">

               </div><!--Menu-->

               <div id="content">

               </div><!--Content-->

               <div id="footer">

               </div><!--Footer-->

        </div>

</body>

</html>

As you can see, we have given the div tag an ID. This is to later be able to define every individual tag in the stylesheet. “ID” is used to mark a tag for unique styling, while “class” is used for reoccurring design elements.

Also, the first div tag in the markup; the “wrapper” we use to wrap around all other tags. This is to later be able to position the web page as we wish.

Step 2 – Linking to Stylesheet

As established, the CSS stylesheet is where you define design elements for your web page. You can choose to create an internal stylesheet or an external. In this tutorial we will show you how to use an external stylesheet.

If you preview your web page in your web browser now, nothing will appear. That is simply because you have not yet given the tags any color or form. And since the stylesheet will be a separate external file, the first thing you have to do is to make sure your web page includes a path to the CSS.

Add this code between <head></head>:

<link rel="stylesheet" type="text/css" href="style.css" />

Step 3 – Creating the CSS

The CSS syntax consists of the selector, property and value. The selector is the tag you want to define in design, the property what kind of attribute you wish to add, and value how the property is added.

The selector, except the body tag, is written to the CSS with either “#” or “.” before the selector name; # defining selector ID and . (dot) defining selector class. A selector can be defined by any number of properties and to work has to be wrapped within { }.

        #selector {

               property:value;

               property:value;

               property:value;

We will now define the following tags as selectors in the stylesheet, according to a number of different properties and values.

Selectors to be defined in the CSS:

· body

· wrapper

· header

· navigation

· menu

· content

· footer

Properties and possible values in the CSS:

The background property can be defined with an image or color, or both. To display an image, the value has to include a path to the image source. To display a color only, a hexadecimal is used. For both, the hexadecimal is defined before the image source.

The color property is used to define the color of text of a selector. The value is written as hexadecimal (e.g. #FFFFFF for white)

The font-family property lets you decide what font type the web page text should have. It is standard to include at least three font-family types, so if the web browser does not support the first, it has more to choose from (e.g. Trebuchet MS, Arial, Times New Roman)

The font-size property defines the size of the font and is written in pixels.

The margin property is used to define the position of the selector. The values are written to define the selector’s sides’ distance from the browser’s window frame, as top, left, bottom, right. As we want to position the web page in the center, we write 0px auto 0px. All the four values do not however always have to be defined.

The width property defines the desired width in pixels we want our selector box to have.

The height property defines the height in pixels

The float property allows us to position elements inside selectors, mainly to the left or right.

Now, to create the CSS file, open your favorite text editor (EditPlus recommended) and save the new document as style.css (the name we gave the css file when creating the path in the web page head tag) in the folder where your web page are located. Then add the following code:

body {

        background: #f3f2f3;

        color: #000000;

        font-family: Trebuchet MS, Arial, Times New Roman;

        font-size: 12px;

#wrapper {

        background: #FFFFFF;

        margin: 60px auto;

        width: 900px;

        height: 1024px;

#header {

        background: #838283;

        height: 200px;

        width: 900px;

#navigation {

        background: #a2a2a2;

        width: 900px;

        height: 20px;

#menu {

        background: #333333;

        float: left;

        width: 200px;

        height: 624px;

#content {

        background: #d2d0d2;

        width: 900px;

        height: 624px;

#footer {

        background: #838283;

        height: 180px;

        width: 900px;

Conclusion

You have now defined each tag/selector by the properties mentioned above. Previewed in the browser, your webpage should now look like this.

View Demo

How To Create a Pure CSS Dropdown Menu

With the help of some advanced selectors a dropdown menu can be easily created with CSS. Throw in some fancy CSS3 properties and you can create a design that was once only achievable with background images and Javascript. Follow this tutorial to see the step by step process of building your own pure CSS dropdown menu.

The menu we’ll be creating features two sub categories that appear once the parent link is activated by a hover. The first series of sub-links appear underneath main nav bar, then the second series of links fly out horizontally from the first dropdown. Take a look at the CSS dropdown menu demo to see it all in action.

View the pure CSS dropdown menu demo

The HTML Structure

<nav>

        <ul>

               <li><a href="#">Home</a></li>

               <li><a href="#">Tutorials</a></li>

               <li><a href="#">Articles</a></li>

               <li><a href="#">Inspiration</a></li>

        </ul>

</nav>

First up we’ll need to create the HTML structure for our CSS menu. We’ll use HTML5 to house the navigation menu in a <nav> element, then add the primary navigation links in a simple unordered list.

<nav>

        <ul>

               <li><a href="#">Home</a></li>

               <li><a href="#">Tutorials</a>

                       <ul>

                               <li><a href="#">Photoshop</a></li>

                               <li><a href="#">Illustrator</a></li>

                               <li><a href="#">Web Design</a></li>

                       </ul>

               </li>

               <li><a href="#">Articles</a>

                       <ul>

                               <li><a href="#">Web Design</a></li>

                               <li><a href="#">User Experience</a></li>

                       </ul>

               </li>

               <li><a href="#">Inspiration</a></li>

        </ul>

</nav>

The first sets of sub-menus can then be added under the “Tutorials” and “Articles” links, each one being a complete unordered list inserted within the<li> of its parent menu option.

<nav>

        <ul>

               <li><a href="#">Home</a></li>

               <li><a href="#">Tutorials</a>

                       <ul>

                               <li><a href="#">Photoshop</a></li>

                               <li><a href="#">Illustrator</a></li>

                               <li><a href="#">Web Design</a>

                                      <ul>

                                              <li><a href="#">HTML</a></li>

                                              <li><a href="#">CSS</a></li>

                                      </ul>

                               </li>

                       </ul>

               </li>

               <li><a href="#">Articles</a>

                       <ul>

                               <li><a href="#">Web Design</a></li>

                               <li><a href="#">User Experience</a></li>

                       </ul>

               </li>

               <li><a href="#">Inspiration</a></li>

        </ul>

</nav>

The secondary sub-menu is nested under the “Web Design” option of the first sub-menu. These links are placed into another unordered list and inserted into the “Web Design” <li>.

So far this leaves us with a neat layout of links with the sub-menus having a clear relation to their parents.

The CSS Styling

nav ul ul {

        display: none;

        nav ul li:hover > ul {

               display: block;

Let’s begin the CSS by getting the basic dropdown functionality working. With CSS specificity and advanced selectors we can target individual elements buried deep in the HTML structure without the need for extra IDs or classes. First hide the sub menus by targeting any UL’s within a UL with the display:none;declaration. In order to make these menus reappear they need to be converted back to block elements on hover of the LI. The > child selector makes sure only the child UL of the LI being hovered is targeted, rather than all sub menus appearing at once.

Description: http://line25.com/wp-content/uploads/2012/css-menu/2.jpg

nav ul {

        background: #efefef;

        background: linear-gradient(top, #efefef 0%, #bbbbbb 100%);

        background: -moz-linear-gradient(top, #efefef 0%, #bbbbbb 100%);

        background: -webkit-linear-gradient(top, #efefef 0%,#bbbbbb 100%);

        box-shadow: 0px 0px 9px rgba(0,0,0,0.15);

        padding: 0 20px;

        border-radius: 10px;

        list-style: none;

        position: relative;

        display: inline-table;

        nav ul:after {

               content: ""; clear: both; display: block;

We can then start to style up the main navigation menu with the help of CSS3 properties such as gradients, box shadows and border radius. Addingposition:relative; will allow us to absolutely position the sub menus according to this main nav bar, then display:inline-table will condense the width of the menu to fit. The clearfix style rule will clear the floats used on the subsequent list items without the use of overflow:hidden, which would hide the sub menus and prevent them from appearing.

nav ul li {

        float: left;

        nav ul li:hover {

               background: #4b545f;

               background: linear-gradient(top, #4f5964 0%, #5f6975 40%);

               background: -moz-linear-gradient(top, #4f5964 0%, #5f6975 40%);

               background: -webkit-linear-gradient(top, #4f5964 0%,#5f6975 40%);

               nav ul li:hover a {

                       color: #fff;

        nav ul li a {

               display: block; padding: 25px 40px;

               color: #757575; text-decoration: none;

The individual menu items are then styled up with CSS rules added to the<li> and the nested anchor. In the browser this will make the link change to a blue gradient background and white text.

nav ul ul {

        background: #5f6975; border-radius: 0px; padding: 0;

        position: absolute; top: 100%;

        nav ul ul li {

               float: none;

               border-top: 1px solid #6b727c;

               border-bottom: 1px solid #575f6a;

               position: relative;

               nav ul ul li a {

                       padding: 15px 40px;

                       color: #fff;

                       nav ul ul li a:hover {

                               background: #4b545f;

The main navigation bar is now all styled up, but the sub menus still need some work. They are currently inheriting styles from their parent elements, so a change of background and the removal of the border-radius and padding fixes their appearance. To make sure they fly out underneath the main menu they are positioned absolutely 100% from the top of the UL (ie, the bottom).
The LI’s of each UL in the sub menu don’t need floating side by side, instead they’re listed vertically with thin borders separating each one. A quick hover effect then darkens the background to act as a visual cue.

nav ul ul ul {

        position: absolute; left: 100%; top:0;

The final step is to position the sub-sub-menus accordingly. These menus will be inheriting all the sub-menu styling already, so all they need is to be positioned absolutely to the right (left:100%) of the relative position of the parent <li>.

The Completed Pure CSS Dropdown Menu

View the pure CSS dropdown menu demo

Pages

Thursday, 14 March 2013

All about CSS

Before your begin:

What is CSS?

Advantages of CSS:

Who Creates and Maintains CSS?

CSS Versions:

css - syntax

The Type Selectors:

The Universal Selectors:

The Descendant Selectors:

The Class Selectors:

The ID Selectors:

The Child Selectors:

The Attribute Selectors:

Multiple Style Rules:

Grouping Selectors:

CSS - Inclusion

Embedded CSS - The <style> Element:

Attributes:

Example:

Inline CSS - The style Attribute:

Attributes:

Example:

This is inline CSS

External CSS - The <link> Element:

Attributes:

Example:

Imported CSS - @import Rule:

Example:

CSS Rules Overriding:

Handling old Browsers:

CSS Comments:

Example:

css_units

css - colors

CSS Colors - Hex Codes:

CSS Colors - Short Hex Codes:

css - fonts

Set the font family:

Set the font style:

Set the font variant:

Set the font weight:

Set the font size:

Set the font size adjust:

Set the font stretch:

Shorthand property :

css – text

CSS – images

CSS – LINK

Set the color of Links:

Set the color of Visited Links:

Change the color of links when mouse is over:

Change the color of active links:

css – tables

The border-collapse Property:

The border-spacing Property:

The caption-side Property:

The empty-cells Property:

The table-layout Property:

css –borders

css – margins

css – lists

css – padding

css - dimension

The height and width Properties:

The line-height Property:

The max-height Property:

The min-height Property:

The max-width Property:

The min-width Property:

css - scrollbars

Basic CSS Implementation and Positioning

Example Files

Table of Contents

Why CSS is Important

Implementing styles

Inline Styles

Element Identifiers