<!DOCTYPE html> <html> <head> <style> span { color: red } :default + span { color: green } span.reverse { color: green } :default + span.reverse { color: red } input { display: none } </style> </head> <body> <form> <div> <input type="checkbox" checked="checked" id="foo"> <span>There should be no red.</span> </div> <div> <input checked="checked"><span class="reverse">There should be no red.</span> </div> </form> </body> </html>