Class selectors
The CSS class selector matches elements based on the contents of their class attribute.
/* All elements with class="spacious" */
.spacious {
margin: 2em;
}
/* All <li> elements with class="spacious" */
li.spacious {
margin: 2em;
}
/* All <li> elements with a class list that includes both "spacious" and "elegant" */
/* For example, class="elegant retro spacious" */
li.spacious.elegant {
margin: 2em;
}
Syntax
.class_name { style properties }
Note that this is equivalent to the following attribute selector:
[class~=class_name] { style properties }
The class_name value must be a valid CSS identifier. HTML class attributes which are not valid CSS identifiers must be escaped before they can be used in class selectors.
Examples
Valid class selectors
HTML
<p class="red">This paragraph has red text.</p>
<p class="red yellow-bg">
This paragraph has red text and a yellow background.
</p>
<p class="red fancy">This paragraph has red text and "fancy" styling.</p>
<p>This is just a regular paragraph.</p>
<!-- The next two paragraphs have class attributes
that contain characters which must be escaped in CSS -->
<p class="item?one">This paragraph has a pink background.</p>
<p class="123item">This paragraph has a yellow background.</p>
CSS
.red {
color: #f33;
}
.yellow-bg {
background: #ffa;
}
.fancy {
font-weight: bold;
text-shadow: 4px 4px 3px #77f;
}
/* In the next two rules, the class attributes must be escaped */
.item\?one {
background-color: pink;
}
.\00003123item {
background-color: yellow;
}
Result
{{EmbedLiveSample('Examples', "", 300)}}
Invalid class selectors
The class selectors in the following rules are not valid CSS identifiers, and will be ignored.
.item?one {
background-color: green;
}
.123item {
background-color: green;
}