opacity

The opacity property sets the transparency of an entire element and its contents.

Since CSS3 Spec ↗

Syntax

opacity: <number 0..1 | %>;

Examples

.disabled { opacity: 0.5; }
.fade { opacity: 0; transition: opacity 0.2s; }
.fade.show { opacity: 1; }
Output
Renders a half-transparent disabled element and a block that fades in when the .show class is added.

Notes

opacity affects the whole element and its children together and creates a new stacking context. To make only a background translucent, use an rgb()/oklch() color with an alpha channel instead.

Browser & runtime support

EnvironmentSince version
chrome 1.0
firefox 1.0
safari 1.0
edge 12

See also