p { background: green; color: white; }
.t1.fail { background: red; color: yellow; }
.fail.t1 { background: red; color: yellow; }
.t2.fail { background: red; color: yellow; }
.fail.t2 { background: red; color: yellow; }
/* Note: This is a valid test even per CSS1, since in CSS1 those rules
         are invalid and should be dropped. */

  <p class="t1">This line should be green.</p>
  <p class="t1 t2">This line should be green.</p>