A super useful one is for styling an element that's next to a checked checkbox. :checked + label { background-color: green; } http://jsbin.com/witaziwu/1/edit

A super useful one is for styling an element that's next to a checked checkbox. :checked + label { background-color: green; } http://jsbin.com/witaziwu/1/edit?html,css,output http://jsbin.com/witaziwu/1/edit?html,css,output Small demo if you want to mess around with it.