In CSS, it’s often necessary to create classes that share common properties or build upon existing styles. While CSS doesn’t support traditional inheritance like some programming languages, there are ways to achieve similar results using class composition and preprocessor tools like LESS and SCSS.
Class Composition
One way to compose classes is by applying multiple classes to a single HTML element. This can be done by separating the class names with spaces in the class attribute.
<div class="something else"></div>
In this example, the div element will inherit properties from both the .something and .else classes.
Preprocessor Tools
Tools like LESS and SCSS provide a more elegant way to compose classes using mixins and extends. A mixin is a group of CSS properties that can be reused throughout your stylesheet.
.rounded_corners {
-moz-border-radius: 8px;
-webkit-border-radius: 8px;
border-radius: 8px;
}
#header {
.rounded_corners;
}
#footer {
.rounded_corners;
}
Similarly, SCSS provides the @extend directive to inherit properties from another class.
.something {
display: inline;
}
.else {
background: red;
}
.composite {
@extend .something;
@extend .else;
}
CSS-only Solution
If you don’t want to use a preprocessor, you can achieve similar results using CSS-only syntax. One way is to define multiple classes with the same properties.
.composite,
.something {
display: inline;
}
.composite,
.else {
background: red;
}
However, this approach can lead to duplicated code and make maintenance more difficult.
Best Practices
When composing classes, it’s essential to follow best practices to keep your CSS organized and maintainable:
- Keep common attributes together in a separate class.
- Use specific or override attributes again for each class that needs them.
- Avoid duplicating code by using preprocessor tools or CSS-only solutions.
By following these guidelines and using the techniques outlined above, you can create robust and reusable CSS classes that make your styling more efficient and effective.