CSS: lighten an element on hover

Question

Assuming an element is at 100% saturation, opacity, etc... how can I have its background become slightly lighter when it is hovered?

The use case is that I'm allowing a user to hover over any element on a page. I don't want to go around determining each colors equivalent at 80% opacity.

One method is to change the opacity: 0.4 but I only want the background to change.

Answer 1

I'm using box-shadow property to control the brightness of the background color, by placing a translucent overlay

Example:

.btn {

  background-color: #0077dd;
  
  display: inline-flex;
  align-content: center;
  padding: 1em 2em;
  border-radius: 5px;
  color: white;
  font-size: 18px;
  margin: 0.5em;
  cursor: pointer;
}

.btn.brighten:hover {
  box-shadow: inset 0 0 0 10em rgba(255, 255, 255, 0.3);
}

.btn.darken:hover {
  box-shadow: inset 0em 0em 0em 10em rgba(0, 0, 0, 0.3);
}

<span class="btn brighten">Brighten on Hover</span>
<span class="btn darken">Darken on Hover</span>