I started to use dFactory: Cookie Notice in my blog beacause of the EU cookie law regulations. This plugin is the easiest way to inform users about site cookie policy, the notification area is fully customizable you can change colors, text, button, appereance etc.

But an important feature is still missing from current version(1.2.37): add notification bar transparency. Fortunately I found the solution in support forum.

Insert this code into your theme’s style.css file:

#cookie-notice {
	background: rgba(0, 0, 0, 0.8) !important;

Now you can define different RGB colors with opacity.