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CSS Tutorial

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How To Add CSS


How to Add CSS

When a browser reads a style sheet, it will format the HTML document according to the information in the style sheet.

There are three ways of inserting a style sheet:

  • External CSS
  • Internal CSS
  • Inline CSS

External CSS

With anexternal style sheet, you can change the look of an entire website by changing just one file!

Each HTML page must include a reference to the external style sheet file inside the <link> element, inside the head section.

Example

External styles are defined within the <link> element, inside the <head> section of an HTML page:

<!DOCTYPE html>
<html>
<head>
<link rel="stylesheet" href="mystyle.css">
</head>
<body>

<h1>This is a heading</h1>
<p>This is a paragraph.</p>

</body>
</html>
Try it Yourself »

An external style sheet can be written in any text editor, and must be saved with a .css extension.

The external .css file should not contain any HTML tags.

Here is how the "mystyle.css" file looks:

"mystyle.css"

body {
  background-color: lightblue;
}

h1 {
  color: navy;
  margin-left: 20px;
}

Note: Do not add a space between the property value (20) and the unit (px):
Incorrect (space):margin-left: 20 px;
Correct (no space):margin-left: 20px;



Internal CSS

An internal style sheet may be used if one single HTML page has a unique style.

The internal style is defined inside the <style> element, inside the head section.

Example

Internal styles are defined within the <style> element, inside the <head> section of an HTML page:

<!DOCTYPE html>
<html>
<head>
<style>
body {
  background-color: linen;
}

h1 {
  color: maroon;
  margin-left: 40px;
}
</style>
</head>
<body>

<h1>This is a heading</h1>
<p>This is a paragraph.</p>

</body>
</html>
Try it Yourself »

Inline CSS

An inline style may be used to apply a unique style for a single element.

To use inline styles, add the style attribute to the relevant element. Thestyle attribute can contain any CSS property.

Example

Inline styles are defined within the "style" attribute of the relevant element:

<!DOCTYPE html>
<html>
<body>

<h1 style="color:blue;text-align:center;">This is a heading</h1>
<p style="color:red;">This is a paragraph.</p>

</body>
</html>
Try it Yourself »

Tip: An inline style loses many of the advantages of a style sheet (by mixingcontent with presentation). Use this method sparingly.


Multiple Style Sheets

If some properties have been defined for the same selector (element) in different style sheets,the value from the last read style sheet will be used. 

Assume that anexternal style sheet has the following style for the <h1> element:

h1{
  color: navy;
}

Then, assume that aninternal style sheet also has the following style for the <h1> element:

h1{
  color: orange;   
}

Example

If the internal style is definedafter the link to the external style sheet, the <h1> elements will be "orange":

<head>
<link rel="stylesheet" type="text/css" href="mystyle.css">
<style>
h1 {
  color: orange;
}
</style>
</head>
Try it Yourself »

Example

However, if the internal style is definedbefore the link to the external style sheet, the <h1> elements will be "navy": 

<head>
<style>
h1 {
  color: orange;
}
</style>
<link rel="stylesheet" type="text/css" href="mystyle.css">
</head>
Try it Yourself »

Cascading Order

What style will be used when there is more than one style specified for an HTML element?

All the styles in a page will "cascade" into a new "virtual" stylesheet by the following rules, where number one has the highest priority:

  1. Inline style (inside an HTML element)
  2. External and internal style sheets (in the head section)
  3. Browser default

So, an inline style has the highest priority, and will override external and internal styles and browser defaults.

Try it Yourself »


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Video: How to add CSS to HTML

Tutorial on YouTube
Tutorial on YouTube



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