Similar to rgb() notation, but with an additional alpha (opacity) value.

.red {
    /* Opaque red */
    color: rgba(255, 0, 0, 1);
}

.red-50p {
    /* Half-translucent red. */
    color: rgba(255, 0, 0, .5);
}

Syntax

rgba(<red>, <green>, <blue>, <alpha>);

Value | Description | —— | —— |<red> | an integer from 0 - 255 or percentage from 0 - 100% |<green> | an integer from 0 - 255 or percentage from 0 - 100% |<blue> | an integer from 0 - 255 or percentage from 0 - 100% |<alpha> | a number from 0 - 1, where 0.0 is fully transparent and 1.0 is fully opaque |