| <!DOCTYPE html> | 
 | <html> | 
 | <meta charset="utf-8"> | 
 | <title>Dynamic change to paint containment (reference)</title> | 
 |  | 
 | <link rel="stylesheet" type="text/css" href="/fonts/ahem.css" /> | 
 |  | 
 | <style> | 
 |   div { | 
 |       font: 25px/1 Ahem; | 
 |   } | 
 |   #wrapper { | 
 |       width: 15em; | 
 |       background: lightgray; | 
 |   } | 
 |   .containment { | 
 |       contain: paint; | 
 |   } | 
 |   .float { | 
 |       box-sizing: border-box; | 
 |       border: 1px solid black; | 
 |   } | 
 |   .left { | 
 |       float: left; | 
 |       width: 1em; | 
 |       height: 2em; | 
 |   } | 
 |   .right { | 
 |       float: right; | 
 |       width: 1em; | 
 |       height: 3em; | 
 |   } | 
 | </style> | 
 |  | 
 | <body> | 
 |   <p>PASS if the boxes with dark colors are NOT floating next to the boxes with | 
 |     light colors.</p> | 
 |   <div id="wrapper"> | 
 |     <div> | 
 |       <div id="container" class="containment"> | 
 |         <div><div class="float left" style="background: lightblue"></div></div> | 
 |         <div class="float right" style="background: lightyellow"></div> | 
 |         <div>XX XXX XXXX X</div> | 
 |       </div> | 
 |       <div class="float left" style="background: blue"></div> | 
 |       <div> | 
 |         <div> | 
 |           <div><div class="float right" style="background: yellow"></div></div> | 
 |           <div>XXX XXXXXX XXXX XX XX</div> | 
 |         </div> | 
 |         <div>XXXX XXXXX XX</div> | 
 |       </div> | 
 |       <div>XXX XXX XX XXXX</div> | 
 |     </div> | 
 |   </div> | 
 | </body> | 
 | </html> |