Semi-transparent menu background

When you start to scroll down the page, the menu background appears. Is there a way to make a background color for the menu show even when you are at the top of the page? basically, my menu items blend into the image on my revolution slider and i’d like to have a black background for the menu that is at about 50% transparency

as always, any hints or tips are very much appreciated

Sure, you can add this in your custom CSS plugin:

.site-header {
    background-color: rgba(0,0,0,0.5);

Please note that in floating mode the opacity is at 90%. In case you want to match them, change 0.5 to 0.9.

fantastic - thanks Vlad!

Ive added this to custom CSS but cant achieve the same objective. Please help