You will notice that the background of this website displays the words DIGITAL. You can make the background opaque in the event that this is a desired component of your design.  Keep in mind that you may need to go back and make your main font a bold font-weight in order for the words to still stand out.  

Here is the code you will need to achieve opacity.  The enlarged words indicate the code that was inserted for this website.

}
#header_container, #main_container {
background-color:#e9e9e9;
opacity:0.9;
border-color:#e9e9e9;