|  | <!DOCTYPE html> | 
|  | <html> | 
|  | <meta charset="utf-8"> | 
|  | <title>Dynamic change to layout 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: layout; | 
|  | } | 
|  | .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 floating next to the boxes with | 
|  | light colors.</p> | 
|  | <div id="wrapper"> | 
|  | <div> | 
|  | <div id="container"> | 
|  | <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> |