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.

Three Ways to Insert CSS

There are three ways of inserting a style sheet:

External CSS

With an external 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 element, inside the head section.

Example

External styles are defined within the element, inside the section of an HTML page:

This is a heading

This is a paragraph.

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 element, inside the head section.

Example

Internal styles are defined within the element, inside the section of an HTML page:

This is a heading

This is a paragraph.

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. The style attribute can contain any CSS property.

Example

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

This is a heading

This is a paragraph.

Tip: An inline style loses many of the advantages of a style sheet (by mixing content 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 an external style sheet has the following style for the element:

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

Example

If the internal style is defined after the link to the external style sheet, the elements will be «orange»:

Example

However, if the internal style is defined before the link to the external style sheet, the elements will be «navy»:

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.

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HTML Styles — CSS

CSS saves a lot of work. It can control the layout of multiple web pages all at once.

CSS = Styles and Colors

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:

• Inline — by using the style attribute inside HTML elements
• Internal — by using a element in the section
• External — by using a element to link to an external CSS file

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 element to blue, and the text color of the

element to red:

Example

A Blue Heading

Internal CSS

An internal CSS is used to define a style for a single HTML page.

An internal CSS is defined in the section of an HTML page, within a element.

The following example sets the text color of ALL the elements (on that page) to blue, and the text color of ALL the

elements to red. In addition, the page will be displayed with a «powderblue» background color:

Example

This is a heading

This is a paragraph.

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 section of each HTML page:

Example

This is a heading

This is a paragraph.

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»:

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:

This is a heading

This is a paragraph.

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:

CSS Padding

The CSS padding property defines a padding (space) between the text and the border.

Example

Use of CSS border and padding properties:

CSS Margin

The CSS margin property defines a margin (space) outside the border.

Example

Use of CSS border and margin properties:

Link to External CSS

External style sheets can be referenced with a full URL or with a path relative to the current web page.

Example

This example uses a full URL to link to a style sheet:

Example

This example links to a style sheet located in the html folder on the current web site:

Example

This example links to a style sheet located in the same folder as the current page:

You can read more about file paths in the chapter HTML File Paths.

Chapter Summary

• Use the HTML style attribute for inline styling
• Use the HTML element to define internal CSS
• Use the HTML element to refer to an external CSS file
• Use the HTML element to store and elements
• Use the CSS color property for text colors
• Use the CSS font-family property for text fonts
• Use the CSS font-size property for text sizes
• Use the CSS border property for borders
• Use the CSS padding property for space inside the border
• Use the CSS margin property for space outside the border

Tip: You can learn much more about CSS in our CSS Tutorial.

HTML Exercises

HTML Style Tags

Tag	Description
	Defines style information for an HTML document
	Defines a link between a document and an external resource

For a complete list of all available HTML tags, visit our HTML Tag Reference.

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