How to add CSS: At the point when a browser reads a style sheet, it will format the HTML document as per the information in the style sheet.

CSS is added to HTML pages to format the document according to information in the style sheet.


In this tutorial, you will learn-

Three Ways to Insert CSS

There are three different ways of inserting a style sheet:

• External CSS

• Internal CSS

• Inline CSS


External CSS

With an external style sheet, you can change the look of a whole site by changing only one document!

Every HTML page should incorporate 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>

<h2>This is a heading</h2>
<p>This is a paragraph.</p>

</body>
</html>

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

The external .css file ought 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 and the unit, (for example, margin-left: 20 px;). The correct way is: margin-left: 20px;


Internal CSS

An internal style sheet might be used on the off chance that 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>

<h2>This is a heading</h2>
<p>This is a paragraph.</p>

</body>
</html>

Inline CSS

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

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

Example

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

<!DOCTYPE html>
<html>
<body>

<h2 style="color:blue;text-align:center;">This is a heading</h2>
<p style="color:red;">This is a paragraph.</p>

</body>
</html>

Tip: An inline style loses a considerable lot of the advantages of a style sheet (by mixing content with presentation). Use this technique sparingly.


Multiple Style Sheets

In the event that a few properties have been defined for a similar selector (element) in various style sheets, the value from the last read style sheet will be used.

Assume that an external style sheet has the following style for the <h2> element:

h2 {
  color: navy;
}

Then, assume that an internal style sheet also has the following style for the <h2> element:

h2 {
  color: orange;   
}

Example

If the internal style is defined after the link to the external style sheet, the <h2> elements will be “orange”:

<!DOCTYPE html>
<html>
<head>
<link rel="stylesheet" type="text/css" href="mystyle.css">
<style>
h2 {
  color: orange;
}
</style>
</head>
<body>

<h2>This is a heading</h2>
<p>The style of this document is a combination of an external stylesheet, and internal style</p>

</body>
</html>

Example

However, if the internal style is defined before the link to the external style sheet, the <h2> elements will be “navy”: 

<!DOCTYPE html>
<html>
<head>
<style>
h1 {
  color: orange;
}
</style>
<link rel="stylesheet" type="text/css" href="mystyle.css">
</head>
<body>

<h2>This is a heading</h2>
<p>The style of this document is a combination of an external stylesheet, and internal style</p>

</body>
</html>

Cascading Order

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

Every one of the styles in a page will “cascade” into another “virtual” style sheet by the accompanying 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

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


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