<!DOCTYPE html>
<!--
 | Properties set on elements that cause anonymous block boxes to be generated
 | still apply to the boxes and content of that element. For example, a border
 | set on the SPAN element in the below example would be drawn open at the end
 | of the first line and at the start of the third line.
 |   https://www.w3.org/TR/CSS21/visuren.html#anonymous-block-level
 -->
<html>
<head>
  <style>
    body {
      font-size: 100px;
    }
    span {
      border: 10px solid green;
    }
  </style>
</head>
<body>
  <span>Wet<div>ATTENTION</div>floor!</span>
</body>
</html>