.cs { color: green; }
 .cs P { background: red; color: yellow; }
 .cs .a { background: red; color: yellow; }
 .cs .span1 span { background: red; color: yellow; }
 .cs .span2 { color: red; }
 .cs .span2 SPAN { color: green; }
 .cs .span2 span { background: red; color: yellow; }
 .ci { color: red; }
 .ci P { background: green; color: white; }
 .ci .a { background: green; color: white; }
 .ci .span1 span { background: green; color: white; }
 .ci .span2 SPAN { background: green; color: white; }

<div>

 <div class="cs">
   <p>This line should be green.</p>
   <p class="A">This line should be green.</p>
   <p class="span1"><SPAN>This line should be green.</SPAN></p>
   <p class="span2"><SPAN>This line should be green.</SPAN></p>
 </div>


</div>