If you want to use modern CSS:
--color_rgb: 0, 0, 0;
background-color: rgba(var(--color_rgb), 0.5);
But it’s still not possible to add alpha to a given color, as in “some other style sheet applied this color in RGB, Hex or something else”.
If you want to use modern CSS:
--color_rgb: 0, 0, 0;
background-color: rgba(var(--color_rgb), 0.5);
But it’s still not possible to add alpha to a given color, as in “some other style sheet applied this color in RGB, Hex or something else”.