Cant customize <code>

im trying to customize <code>
tag colors but no matter what change i make nothing happens.

code {
    color: #eee;
    background-color: #1F1F1F;
}

its just basic, but for some reason the program doesnt detect it and decides to just highlight the whole thing white making text impossible to read.

Can you share a link to the page you are testing this on?