chromium/third_party/blink/web_tests/css3/selectors3/xml/css3-modsel-14d.css

p { background: green; color: white; }
.t1:not(.t2) { background: red; color: yellow; }
:not(.t2).t1 { background: red; color: yellow; }
.t2:not(.t1) { background: red; color: yellow; }
:not(.t1).t2 { background: red; color: yellow; }