Board Thread:Support Requests - Designing Your Wikia/@comment-3398633-20160706061658/@comment-5501257-20160706074449

You can use this code:

body.skin-monobook { background-color: rgba(your color code,your opacity value); }

Example: body.skin-monobook { background-color: rgba(255,255,255,0.5); }

You can read it more here: http://stackoverflow.com/questions/5135019/css-opacity-only-to-background-color-not-the-text-on-it