Cascading Style Sheets (CSS)



About 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 the 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. Cascading Style Sheets level 1 (CSS1) 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 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. 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 a 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 be color, border, etc.

  • Value: Values are assigned to properties. For example, color property can have the value either red or #F1F1F1 etc.
selector { property: value }

Example
table{ border :1px solid #C00; }

Here table is a selector and border is a property and the given value 1px solid #C00 is the value of that property.
Table Options border-collapse: collapse; /* Table Border line Traced */

Selectors

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, the style rule will apply to <em> element only when it lies inside the <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 a given element. Consider the following example:

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

h1 { font-family: "Arial Narrow", Arial, sans-serif; font-size: 24px; font-style: normal; font-variant: normal; font-weight: 700; line-height: 26.4px; } h3 { font-family: "Arial Narrow", Arial, sans-serif; font-size: 14px; font-style: normal; font-variant: normal; font-weight: 700; line-height: 15.4px; } p { font-family: "Arial Narrow", Arial, sans-serif; font-size: 14px; font-style: normal; font-variant: normal; font-weight: 400; line-height: 20px; } blockquote { font-family: "Arial Narrow", Arial, sans-serif; font-size: 21px; font-style: normal; font-variant: normal; font-weight: 400; line-height: 30px; } pre { font-family: "Arial Narrow", Arial, sans-serif; font-size: 13px; font-style: normal; font-variant: normal; font-weight: 400; line-height: 18.5714px; } /* This text is in Arial Narrow */ 
.class { 
	font-family: Arial Narrow,Arial,sans-serif; 
}