.one {}
.one.two {}

.one .two {}
.one.two .three.four {}


div.one.two {}
div#one.two {}
div.one#two {}
div .one {}
div .one.two {}

.one.two.three.four.five.six.seven.eight.nine.ten.eleven.twelve.thirteen.fourteen.fifteen.sixteen.seventeen.eighteen.nineteen.twenty {}

.one, .two {}
.one.two, .three.four {}
.one .two.three, .four {}