CSS: ::selection { background: #000000; color: #ffffff } not appearing as full black

Question

::selection { background: #000000; color: #ffffff } 

Is resulting in a dark grey selection color, not full black (#000000). Changing opacity makes no difference.

How do I make the selection color appear as #ffffff?

Answer 1

This worked for me:

::selection {
   background: rgba(0, 0, 0, 0.99);
   color: #FFF;
}