CSS: How do I create custom text markup?

In fact, this customization is somewhat extravagant, but there are certainly reasons in which this makes sense and namely the background color for text markers. These are usually controlled by the browser used, but CSS can also be used to control the text color as well as the background for markups.

::-moz-selection { 
   color:#fff; 
   background:#000; 
}
::selection { 
   color:#fff; 
   background:#000; 
}