CSS
What is CSS?
Cascading Style Sheets (CSS) is used to format the layout of a webpage.
With CSS, you can control the color, font, the size of text, the spacing between elements, how elements are positioned and laid out, what background images or background colors are to be used, different displays for different devices and screen sizes, and much more!
Tip:?The word?cascading?means that a style applied to a parent element will also apply to all children elements within the parent. So, if you set the color of the body text to "blue", all headings, paragraphs, and other text elements within the body will also get the same color (unless you specify something else)!
Using CSS
CSS can be added to HTML documents in 3 ways:
The most common way to add CSS, is to keep the styles in external CSS files. However, in this tutorial we will use inline and internal styles, because this is easier to demonstrate, and easier for you to try it yourself.
Inline CSS
An inline CSS is used to apply a unique style to a single HTML element.
An inline CSS uses the?style?attribute of an HTML element.
The following example sets the text color of the?<h1>?element to blue, and the text color of the?<p>?element to red:
Example
<h1?style="color:blue;">A Blue Heading</h1>
<p?style="color:red;">A red paragraph.</p>
Internal CSS
An internal CSS is used to define a style for a single HTML page.
An internal CSS is defined in the?<head>?section of an HTML page, within a?<style>?element.
The following example sets the text color of ALL the?<h1>?elements (on that page) to blue, and the text color of ALL the?<p>?elements to red. In addition, the page will be displayed with a "powderblue" background color:?
Example
<!DOCTYPE?html>
<html>
<head>
<style>
body?{background-color:?powderblue;}
h1???{color:?blue;}
p????{color:?red;}
</style>
</head>
<body>
<h1>This is a heading</h1>
<p>This is a paragraph.</p>
</body>
</html>
External CSS
An external style sheet is used to define the style for many HTML pages.
To use an external style sheet, add a link to it in the?<head>?section of each HTML page:
Example
<!DOCTYPE?html>
<html>
<head>
??<link?rel="stylesheet"?href="styles.css">
</head>
<body>
<h1>This is a heading</h1>
<p>This is a paragraph.</p>
</body>
</html>
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The external style sheet can be written in any text editor. The file must not contain any HTML code, and must be saved with a .css extension.
Here is what the "styles.css" file looks like:
"styles.css":
body?{
??background-color:?powderblue;
}
h1?{
?color:?blue;
}
p?{
??color:?red;
}
Tip:?With an external style sheet, you can change the look of an entire web site, by changing one file!
CSS Colors, Fonts and Sizes
Here, we will demonstrate some commonly used CSS properties. You will learn more about them later.
The CSS?color?property defines the text color to be used.
The CSS?font-family?property defines the font to be used.
The CSS?font-size?property defines the text size to be used.
Example
Use of CSS color, font-family and font-size properties:
<!DOCTYPE?html>
<html>
<head>
<style>
h1?{
??color:?blue;
??font-family:?verdana;
??font-size:?300%;
}
p?{
?color:?red;
?font-family:?courier;
?font-size:?160%;
}
</style>
</head>
<body>
<h1>This is a heading</h1>
<p>This is a paragraph.</p>
</body>
</html>
CSS Border
The CSS?border?property defines a border around an HTML element.
Tip:?You can define a border for nearly all HTML elements.
Example
Use of CSS border property:?
p?{
??border:?2px solid powderblue;
}
CSS Padding
The CSS?padding?property defines a padding (space) between the text and the border.