How Can You Simulate Conditional Logic in Your CSS?

Can You Use Conditional Logic in CSS?

If-else conditions are not natively supported in CSS. However, there are several methods to achieve similar functionality.

CSS Classes:

If you have control over the HTML, you can use CSS classes to apply different styles based on a variable. For example:

<p class="normal">Text</p>
<p class="active">Text</p>

p.normal {
  background-position: 150px 8px;
}
p.active {
  background-position: 4px 8px;
}

CSS Preprocessors (e.g., Sass):

CSS preprocessors allow for the use of control structures, including conditionals. For instance, in Sass:

$type: monster;
p {
  @if $type == "ocean" {
    color: blue;
  } @else if $type == "matador" {
    color: red;
  } @else if $type == "monster" {
    color: green;
  } @else {
    color: black;
  }
}

CSS Custom Properties:

Custom properties can be evaluated at runtime in supported browsers. You can use them to set styles based on conditions:

:root {
  --main-bg-color: brown;
}

.one {
  background-color: var(--main-bg-color);
}

.two {
  background-color: black;
}

Server-Side Preprocessing:

You can also preprocess your stylesheet with a server-side language. For example, in PHP:

p {
  background-position: <?php echo (@$_GET['foo'] == 'bar')? "150" : "4"; ?>px 8px;
}

Other Techniques:

For more complex scenarios, you can explore CSS tricks and techniques mentioned in articles such as "If/Else in CSS" by Ahmad Shadeed.

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