The selector points to the HTML element you want to style.

The declaration block contains one or more declarations separated by semicolons.

Each declaration includes a CSS property name and a value, separated by a colon.

A CSS declaration always ends with a semicolon, and declaration blocks are surrounded by curly braces.

In the following example all <p> elements will be center-aligned, with a red text color:

The element selector selects elements based on the element name.

You can select all <p> elements on a page like this (in this case, all <p> elements will be center-aligned, with a red text color):

The id selector uses the id attribute of an HTML element to select a specific element.

The id of an element should be unique within a page, so the id selector is used to select one unique element!

To select an element with a specific id, write a hash (#) character, followed by the id of the element.

The style rule below will be applied to the HTML element with id = "para1":

The class selector selects elements with a specific class attribute.

To select elements with a specific class, write a period (.) character, followed by the name of the class.

In the example below, all HTML elements with class = "center" will be red and center-aligned:

You can also specify that only specific HTML elements should be affected by a class.

In the example below, only <p> elements with class = "center" will be center-aligned:

HTML elements can also refer to more than one class.

In the example below, the <p> element will be styled according to class = "center" and to class = "large":

If you have elements with the same style definitions, like this:

It will be better to group the selectors, to minimize the code.

To group selectors, separate each selector with a comma.

In the example below we have grouped the selectors from the code above:

Comments are used to explain the code, and may help when you edit the source code at a later date.

Comments are ignored by browsers.

A CSS comment starts with /* and ends with */. Comments can also span multiple lines:

In HTML, a color can be specified by using a color name:

You can set the background color for HTML elements:

You can set the color of text:

Hello World

Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat volutpat.

Ut wisi enim ad minim veniam, quis nostrud exerci tation ullamcorper suscipit lobortis nisl ut aliquip ex ea commodo consequat.

You can set the color of borders:

Hello World

Hello World

Hello World

In HTML, colors can also be specified using RGB values, HEX values, HSL values, RGBA values, and HSLA values:

Same as color name "Tomato":

Same as color name "Tomato", but 50% transparent:

In HTML, a color can be specified as an RGB value, using this formula:

rgb(red, green, blue)

Each parameter (red, green, and blue) defines the intensity of the color between 0 and 255.

For example, rgb(255, 0, 0) is displayed as red, because red is set to its highest value (255) and the others are set to 0.

To display the color black, all color parameters must be set to 0, like this: rgb(0, 0, 0).

To display the color white, all color parameters must be set to 255, like this: rgb(255, 255, 255).

Experiment by mixing the RGB values below:

Colors Example

Gray's Example

Shades of gray are often defined using equal values for all the 3 light sources:

In HTML, a color can be specified using a hexadecimal value in the form:

#rrggbb

Where rr (red), gg (green) and bb (blue) are hexadecimal values between 00 and ff (same as decimal 0-255).

For example, #ff0000 is displayed as red, because red is set to its highest value (ff) and the others are set to the lowest value (00).

Colors Example

Gray's Example

Shades of gray are often defined using equal values for all the 3 light sources:

The background-color property specifies the background color of an element.

The background color of a page is set like this:

With CSS, a color is most often specified by:

• a valid color name - like "red"
• a HEX value - like "#ff0000"
• an RGB value - like "rgb(255,0,0)"

Look at CSS Color Values for a complete list of possible color values.

In the example below, the <h1>, <p>, and <div> elements have different background colors:

The background-image property specifies an image to use as the background of an element.

By default, the image is repeated so it covers the entire element.

The background image for a page can be set like this:

By default, the background-image property repeats an image both horizontally and vertically.

Some images should be repeated only horizontally or vertically, or they will look strange

If the image is repeated only horizontally (background-repeat: repeat-x;), the background will look better:

Showing the background image only once is also specified by the background-repeat property:

To specify that the background image should be fixed (will not scroll with the rest of the page), use the background-attachment property:

To shorten the code, it is also possible to specify all the background properties in one single property. This is called a shorthand property.

The shorthand property for background is background:

When using the shorthand property the order of the property values is:

• background-color
• background-image
• background-repeat
• background-attachment
• background-position

The CSS border properties allow you to specify the style, width, and color of an element's border.

I have borders on all sides.

I have a red bottom border.

I have rounded borders.

I have a blue left border.

The border-style property specifies what kind of border to display.

The following values are allowed:

• dotted - Defines a dotted border
• dashed - Defines a dashed border
• solid - Defines a solid border
• double - Defines a double border
• groove - Defines a 3D grooved border. The effect depends on the border-color value
• ridge - Defines a 3D ridged border. The effect depends on the border-color value
• inset - Defines a 3D inset border. The effect depends on the border-color value
• outset - Defines a 3D outset border. The effect depends on the border-color value
• none - Defines no border
• hidden - Defines a hidden border

The border-style property can have from one to four values (for the top border, right border, bottom border, and the left border).

Result:

A dotted border.

A dashed border.

A solid border.

A double border.

A groove border. The effect depends on the border-color value.

A ridge border. The effect depends on the border-color value.

An inset border. The effect depends on the border-color value.

An outset border. The effect depends on the border-color value.

No border.

A hidden border.

A mixed border.

Note: None of the OTHER CSS border properties described below will have ANY effect unless the border-style property is set!

The border-width property specifies the width of the four borders.

The width can be set as a specific size (in px, pt, cm, em, etc) or by using one of the three pre-defined values: thin, medium, or thick.

The border-width property can have from one to four values (for the top border, right border, bottom border, and the left border).

5px border-width