Just a short one.
Have you been in the situation where you’d like to be able to enable a style only when both classes are defined for an element? For example:
<ul> <li class="level-0">Home</li> <li class="level-0">Electronics</li> <li class="level-1">Televisual Boxes</li> <li class="level-1 over">Kettles</li> <li class="level-0">Furniture</li> <li class="level-0">Clearance</li> </ul>
We’ll ignore the fact that we could have used the :hover pseudo-class, and that we could have used an additional <ul></ul> to define the level-1 items.
Logical AND (&&)
We can invoke a specific over CSS class on only the level-1 items with the following:
li.level-1.over { background-color: red; }
Keeping adding additional class by chaining with the .className syntax.
Logical OR (||)
Of course, to OR the classes you simply comma-separate them:
li.class1, li.class2 { background-color: green; }
