CSS3 Rounded Corners

Browser Support

The numbers in the table specify the first browser version that fully supports the property.

Numbers followed by -webkit- or -moz- specify the first version that worked with a prefix.

Property
border-radius	9.0	5.0 4.0 -webkit-	4.0 3.0 -moz-	5.0 3.1 -webkit-	10.5

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CSS3 border-radius Property

With CSS3, you can give any element "rounded corners", by using the border-radius property.

#rcorners1 {
    border-radius: 25px;
    background: #8AC007;
    padding: 20px; 
    width: 200px;
    height: 150px; 
}

#rcorners2 {
    border-radius: 25px;
    border: 2px solid #8AC007;
    padding: 20px; 
    width: 200px;
    height: 150px; 
}

#rcorners3 {
    border-radius: 25px;
    background: url(paper.gif);
    background-position: left top;
    background-repeat: repeat;
    padding: 20px; 
    width: 200px;
    height: 150px; 
}

Tip: The border-radius property is actually a shorthand property for the border-top-left-radius, border-top-right-radius, border-bottom-right-radius and border-bottom-left-radius properties.

CSS3 border-radius - Specify Each Corner

If you specify only one value for the border-radius property, this radius will be applied to all 4 corners.

However, you can specify each corner separately if you wish. Here are the rules:

• Four values: first value applies to top-left, second value applies to top-right, third value applies to bottom-right, and fourth value applies to bottom-left corner
• Three values: first value applies to top-left, second value applies to top-right and bottom-left, and third value applies to bottom-right
• Two values: first value applies to top-left and bottom-right corner, and the second value applies to top-right and bottom-left corner
• One value: all four corners are rounded equally

#rcorners4 {
    border-radius: 15px 50px 30px 5px;
    background: #8AC007;
    padding: 20px; 
    width: 200px;
    height: 150px; 
}

#rcorners5 {
    border-radius: 15px 50px 30px;
    background: #8AC007;
    padding: 20px; 
    width: 200px;
    height: 150px; 
}

#rcorners6 {
    border-radius: 15px 50px;
    background: #8AC007;
    padding: 20px; 
    width: 200px;
    height: 150px; 
}

You could also create elliptical corners:

#rcorners7 {
    border-radius: 50px/15px;
    background: #8AC007;
    padding: 20px; 
    width: 200px;
    height: 150px; 
}

#rcorners8 {
    border-radius: 15px/50px;
    background: #8AC007;
    padding: 20px; 
    width: 200px;
    height: 150px; 
}

#rcorners9 {
    border-radius: 50%;
    background: #8AC007;
    padding: 20px; 
    width: 200px;
    height: 150px;
}

CSS3 Rounded Corners Properties

Property	Description
border-radius	A shorthand property for setting all the four border-*-*-radius properties
border-top-left-radius	Defines the shape of the border of the top-left corner
border-top-right-radius	Defines the shape of the border of the top-right corner
border-bottom-right-radius	Defines the shape of the border of the bottom-right corner
border-bottom-left-radius	Defines the shape of the border of the bottom-left corner

CSS3 Introduction

CSS3 Modules

CSS3 has been split into "modules". It contains the "old CSS specification" (which has been split into smaller pieces). In addition, new modules are added.

Some of the most important CSS3 modules are:

• Selectors
• Box Model
• Backgrounds and Borders
• Image Values and Replaced Content
• Text Effects
• 2D/3D Transformations
• Animations
• Multiple Column Layout
• User Interface

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CSS3 Recommendation

Most of the CSS3 Modules are W3C Recommendations, and most of the new CSS3 properties are already implemented in modern browsers.

CSS Pseudo-classes

Syntax

The syntax of pseudo-classes:

selector:pseudo-class {
    property:value;
}

Anchor Pseudo-classes

Links can be displayed in different ways:

/* unvisited link */
a:link {
    color: #FF0000;
}

/* visited link */
a:visited {
    color: #00FF00;
}

/* mouse over link */
a:hover {
    color: #FF00FF;
}

/* selected link */
a:active {
    color: #0000FF;
}

Note: a:hover MUST come after a:link and a:visited in the CSS definition in order to be effective!a:active MUST come after a:hover in the CSS definition in order to be effective! Pseudo-class names are not case-sensitive.

Pseudo-classes and CSS Classes

Pseudo-classes can be combined with CSS classes:

a.highlight:hover {
    color: #ff0000;
}

CSS - The :first-child Pseudo-class

The :first-child pseudo-class matches a specified element that is the first child of another element.

Match the first <p> element

In the following example, the selector matches any <p> element that is the first child of any element:

p:first-child {
    color: blue;
}

Match the first <i> element in all <p> elements

In the following example, the selector matches the first <i> element in all <p> elements:

p i:first-child {
    color: blue;
}

Match all <i> elements in all first child <p> elements

In the following example, the selector matches all <i> elements in <p> elements that are the first child of another element:

p:first-child i {
    color: blue;
}

CSS - The :lang Pseudo-class

The :lang pseudo-class allows you to define special rules for different languages.

In the example below, :lang defines the quotation marks for <q> elements with lang="no":

<html>
<head>
<style>
q:lang(no) {
    quotes: "~" "~";
}
</style>
</head>

<body>
<p>Some text <q lang="no">A quote in a paragraph</q> Some text.</p>
</body>
</html>

CSS Pseudo-elements

Syntax

The syntax of pseudo-elements:

selector::pseudo-element {
    property:value;
}

Notice the double colon notation - ::first-line versus :first-line

The double colon replaced the single-colon notation for pseudo-elements in CSS3. This was an attempt from W3C to distinguish between pseudo-classes and pseudo-elements.

The single-colon syntax was used for both pseudo-classes and pseudo-elements in CSS2 and CSS1.

For backward compatibility, the single-colon syntax is acceptable for CSS2 and CSS1 pseudo-elements.

The ::first-line Pseudo-element

The ::first-line pseudo-element is used to add a special style to the first line of a text.

The following example formats the first line of the text in all <p> elements:

p::first-line {
    color: #ff0000;
    font-variant: small-caps;
}

Note: The ::first-line pseudo-element can only be applied to block-level elements.

The following properties apply to the ::first-line pseudo-element:

• font properties
• color properties
• background properties
• word-spacing
• letter-spacing
• text-decoration
• vertical-align
• text-transform
• line-height
• clear

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The ::first-letter Pseudo-element

The ::first-letter pseudo-element is used to add a special style to the first letter of a text.

The following example formats the first letter of the text in all <p> elements: 

p::first-letter {
    color: #ff0000;
    font-size: xx-large;
}

Note: The ::first-letter pseudo-element can only be applied to block-level elements.

The following properties apply to the ::first-letter pseudo- element: 

• font properties
• color properties 
• background properties
• margin properties
• padding properties
• border properties
• text-decoration
• vertical-align (only if "float" is "none")
• text-transform
• line-height
• float
• clear

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Pseudo-elements and CSS Classes

Pseudo-elements can be combined with CSS classes: 

p.intro::first-letter {
    color: #ff0000;
    font-size:200%;
}

Multiple Pseudo-elements

Several pseudo-elements can also be combined.

In the following example, the first letter of a paragraph will be red, in an xx-large font size. The rest of the first line will be blue, and in small-caps. The rest of the paragraph will be the default font size and color:

p::first-letter {
    color: #ff0000;
    font-size: xx-large;
}

p::first-line {
    color: #0000ff;
    font-variant: small-caps;
}

CSS - The ::before Pseudo-element

The ::before pseudo-element can be used to insert some content before the content of an element.

The following example inserts an image before the content of each <h1> element:

h1::before {
    content: url(smiley.gif);
}

CSS - The ::after Pseudo-element

The ::after pseudo-element can be used to insert some content after the content of an element.

The following example inserts an image after the content of each <h1> element:

h1::after {
    content: url(smiley.gif);
}

CSS - The ::selection Pseudo-element

The ::selection pseudo-element matches the portion of an element that is selected by a user.

The following CSS properties can be applied to ::selection: color, background, cursor, and outline.

The following example makes the selected text red on a yellow background:

::selection {
    color: red; 
    background: yellow;
}