CSS Pseudo Elements
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CSS gives us a lot of flexibility in style, but very little in creating new elements. However, there is one way we can add new containers of content, and content, with CSS, and that is using pseudo elements. Pseudo elements use the keyword :before
and :after
.
How Pseudo Elements Work
A pseudo element is attached to an already existing HTML element on the page you are targeting. The reason we have :before
and :after
is because we can have content before (but within the element we select) or after.
To bring this to life, let's look at an example. Here we will add some text before and after a div.
<div class="my-container">Name</div>
.my-container:before {
content: 'Hello My ';
color: orange;
}
.my-container:after {
content: ' Is...';
color: pink;
}
How it looks:
Name
Icons
Psuedo elements have one of their main use cases in CSS icons. On Fjolt, we use FontAwesome quite extensively. If we want to add an icon before an anchor, for example, we can easily do that with a pseudo element if we know the icon code, which is given on the FontAwesome icon page:
p:before {
font-weight: 100;
content: '\f058';
margin: 0 0.5rem 0 0;
font-family: 'Font Awesome 5 Pro';
}
I have an icon!
Covers
We aren't limited to inline styles for pseudo elements, though. We can also set a pseudo element to have an absolute position, so it can take up an entire container. This is frequently used to create a 'backdrop' for modals:
#container {
position: relative;
padding: 1rem;
box-sizing: border-box;
overflow: hidden;
height: 235px;
border-radius: 10px;
}
#container:after {
content: '';
position: absolute;
top: 0;
left: 0;
width: 100%;
height: 100%;
background: linear-gradient(45deg, #0037ff, #00adff);
opacity: 0.2;
}
#modal {
background: white;
position: absolute;
left: 20%;
z-index: 10;
border-radius: 10px;
width: 60%;
height: 200px;
box-shadow: 0 2px 20px rgb(0 0 0 / 10%);
padding: 1rem;
box-sizing: border-box;
font-weight: 600;
}
<div id="container">
<div id="modal">
I am a modal!
</div>
</div>
More Tips and Tricks for CSS
- How to vertically center text and HTML elements with CSS
- CSS Colors
- CSS Pseudo Elements
- A Guide to CSS Selectors
- The Quick Guide to Dark Mode
- Automating CSS Dark Mode
- An Interactive Guide to CSS Flex Box
- Putting Javascript in Your CSS with Paint Worklets
- How to Create Animated Cards with WebGL and Three.js
- Making 3D CSS Flippable Cards