How to Easily Darken Element Backgrounds with CSS?

Making Elements Darker with CSS: A Convenient Trick

Current methods for darkening element backgrounds using CSS can be tedious, requiring the manual creation of a darker color hex code. This article presents a convenient alternative that leverages background-image to elegantly achieve the desired darkening effect.

The Problem: Tedious Manual Darkening

When hovering over a button, it is common to darken the background color to enhance user interactivity. Previously, this was achieved by specifying a darker hex code in the CSS, as shown below:

.Button:hover {
  background-color: #ALittleDarkerHex;
}

However, finding a suitable darker hex code can be time-consuming and imprecise.

The Solution: Background-Image Overlay

Instead of modifying the background-color property, this technique introduces a dark layer on top of the element using background-image and linear-gradient:

.button:hover {
  background-image: linear-gradient(rgb(0 0 0/40%) 0 0);
}

This dark overlay is applied over the existing background color, creating a subtle darkening effect without altering the text color. The 40% opacity allows the underlying background color to remain visible while reducing its intensity.

Implementation and Example

To demonstrate this technique, consider the following HTML and CSS:

<div class="button"> some text </div>
<div class="button">
<pre class="brush:php;toolbar:false">.button {
  display: inline-block;
  color: #fff;
  padding: 10px 20px;
  font-size: 20px;
  background-color: red;
}

.button:hover {
  background-image: linear-gradient(rgb(0 0 0/40%) 0 0);
}

The buttons will display their original background colors, and when hovered over, a subtle darkening effect will be applied, regardless of the background color.