What is CSS?
CSS refers to Cascading Style Sheets, In general styles define how to display elements on the web page.
By CSS, we can define a style for a web page and make it standard for all web pages on the website, changes to the style will be applicable to all pages on the same time. another point of view, CSS responsible for formatting elements of a page, this feature makes the HTML/XHTML responsible on defining the content of the page, and does not have a role in formatting the elements.
CSS created by W3C to solve a problem of HTML/XHTML, suppose you want to design your page in some specifications for fonts and colors used, then without using CSS, you have to write these specification for each page you want to apply this design to it, moreover, you might need to apply same design specifications on two different places on the same page, without CSS, you have to write it where ever you want it, this will make page design more complex and poor.
A CSS rule consists of two parts, first one is the selector, and the second one is the declaration part.
Normally, the selector is an HTML element that you want to style.
The declaration part, consists of properties and its values, each property defines a specific style that makes special touches to an element.
/* Declaration Part */
- The above lines of code, makes a rule for styling paragraphs in any HTML/XHTML document.
- This rule displays paragraphs in font color black and size of 13px, and justifies it to its parent borders.
- The p is an HTML element that refers to define paragraphs, and it is the selector in this rule.
- Properties are defined in the declaration block.
- Declaration block begins with an open curly bracket, and finishes with a close curly bracket.
- Comments in CSS are enclosed within /* and */.
- Each property definition ends with a semi-colon.
- In this example I’m just showing the syntax of CSS, next lessons we’ll talk in deep details about properties and its values.
How to apply?
This example shows how to apply the above rule in an XHTML document.
- Firstly, save the above rule in a file for example style.css, it is important that the extension of the file be .css.
- In each page you need to apply your style, just link the style sheet to your page.
- Look at this example:
<!DOCTYPE html PUBLIC “-//W3C//DTD XHTML 1.0 Transitional//EN”
<!—Use the link tag to link to your style sheet –>
<link rel=”stylesheet” type=”text/css” href=”style.css” />
<p> This is a paragraph that has special style defined in the CSS style sheet. </p>
<p> Another Paragraph has same styles it is amazing idea </p>
End of Part I.
To download this part as PDF file click here: CSS Tutorial – Lesson 1 Part I