How to use CSS

Author: MDBootstrap

How to use 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 style sheet
  • Internal style sheet
  • Inline style

External Style Sheet

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

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

                        <link rel="stylesheet" type="text/css" href="mystyle.css">

An external style sheet can be written in any text editor. The file should not contain any html tags. The style sheet file must be saved with a .css extension.

You can download example by clicking a button below and open it in the code editor and in the browser:

Download example

Internal Style Sheet

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

Internal styles are defined within the <style> element of an HTML page:

                          body {
                            background-color: linen;
                          h1 {
                            color: maroon;
                            margin-left: 40px;

It's a good practice to place your CSS code within the <head> elements, however it's not necessary.

This will also work:

                Just an empty head for use of the example

            <p>I am a paragraph</p>

                .example-class {
                    color: blue;

            <h3 class="example-class">I am a heading</h3>

Inline Styles

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. The style attribute can contain any CSS property.

The example below shows how to change the color and the left margin of a <h3> element:

                      <h3 style="color:green;">I am a heading</h3>

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

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" style sheet 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.

                          .orange-color {
                            color: orange;
                        <h3 class="orange-color" style="color: red;">I am an example with the class "orange-color", but I am red!</h3>

Live preview

I am an example with the class "orange-color", but I am red!

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