<html>
  <head>
    <title>Block with over-contrained margins+borders+padding+width = containing block width</title>
    <style>
      body { width: 300px; margin: 0; }
      p { background: green; width: 200px; height: 100px; margin: 0; position: absolute }
    </style>
  </head>
  <body>
    <p style="top: 20px; left: 470px"></p>
    <p style="top: 140px; left: 430px"></p>
    <p style="top: 260px; left: 520px"></p>
    <!-- https://github.com/servo/servo/issues/8721: should be left: 380px -->
    <p styl