CSS Selector “(A or B) and C”?

Question

This should be simple, but I\'m having trouble finding the search terms for it.
Let\'s say I have this:

Foo


        
      

Answer 1

If you have this:

Foo
Bar
Baz

And you only want to select the elements which have .x and (.a or .b), you could write:

.x:not(.c) { ... }

but that's convenient only when you have three "sub-classes" and you want to select two of them.

Selecting only one sub-class (for instance .a): .a.x

Selecting two sub-classes (for instance .a and .b): .x:not(.c)

Selecting all three sub-classes: .x