What is CSS?
· CSS stands for Cascading Style Sheets
· Styles define how to display HTML elements
· Styles are normally stored in Style Sheets
CSS Syntax:
The CSS syntax is made up of three parts: a selector, a property and a value:
selector {property: value}
· The selector is HTML element/tag you wish to define,
· The property is the attribute you wish to change, and each property can take a value.
· The property and value are separated by a colon, and surrounded by curly braces.
Examples:
· body {color: black}
Note: If the value is multiple words, put quotes around the value:
· p {font-family: "sans serif"}
Note: If you wish to specify more than one property, you must separate each property with a semicolon. The example below shows how to define a center aligned paragraph, with a red text color.
· p {text-align:center;color:red}
To make the style definitions more readable, you can describe one property on each line, like this:
p
{
text-align: center;
color: black;
font-family: arial
}
Grouping:
You can group selectors. Separate each selector with a comma. In the example below we have grouped all the header elements. All header elements will be displayed in green text color:
· h1,h2,h3,h4,h5,h6
{
color: green
}
The class Selector:
· With the class selector you can define different styles for the same type of HTML element.
· Say that you would like to have two types of paragraphs in your document: one right-aligned paragraph, and one center-aligned paragraph. Here is how you can do it with styles:
o <p class="right">
This paragraph will be right-aligned.
</p>
o <p class="center">
This paragraph will be center-aligned.
</p>
Note: To apply more than one class per given element, the syntax is:
· <p class="center bold">
This is a paragraph.
</p>
Do NOT start a class name with a number! It will not work in Mozilla/Firefox
Add Styles to Elements with Particular Attributes:
· You can also apply styles to HTML elements with particular attributes.
· The style rule below will match all input elements that have a type attribute with a value of "text"
o input[type="text"] {background-color: blue}
The id Selector:
· You can also define styles for HTML elements with the id selector. The id selector is defined as a #.
· The style rule below will match the element that has an id attribute with a value of "green":
o #green {color: green}
· The style rule below will match the p element that has an id with a value of "para1":
o p#para1
{
text-align: center;
color: red
}
Do NOT start an ID name with a number! It will not work in Mozilla/Firefox.
Internal Style Sheet:
· An internal style sheet should be used when a single document has a unique style. You define internal styles in the head section by using the <style> tag, like this:
o <head>
<style type="text/css">
hr {color: sienna}
p {margin-left: 20px}
body {background-image: url("images/back40.gif")}
</style>
</head>
Inline Styles:
· An inline style loses many of the advantages of style sheets by mixing content with presentation. Use this method sparingly, such as when a style is to be applied to a single occurrence of an element.
· To use inline styles you use the style attribute in the relevant tag. The style attribute can contain any CSS property. The example shows how to change the color and the left margin of a paragraph:
o <p style="color: sienna; margin-left: 20px">
This is a paragraph
</p>
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