ner .inline { color: lime; display: inline; }

   /* middle */
   .float .block { height: 3em; margin: 0; background: lime; display: block; }
   .inner .block { height: 3em; margin: 0; background: red; display: block; }

  </style>
 </head>
 <body>
  <p class="control">Ahem_font_would_be_nice_for_this_test.</p>
  <p>There should just be a single green square below (with a black border).</p>

  <div class="container">
   <div class="inner">
    <div class="inline">XXXXX</div>
    <div class="block"></div>
  