<!DOCTYPE html>
<html>
<head>
<title>CSS Borders: border-top-width: thin equals 1px</title>
<link rel="help" href="https://drafts.csswg.org/css-backgrounds-3/#border-width">
<link rel="match" href="reference/border-top-width-1px-ref.html">
<meta name="assert" content="The 'thin' keyword for 'border-top-width' is 1px." />
<style>
  .red-if-too-thin { height: 1px; background: red; }
  .cb { position: relative; }
  .red-if-too-thick { height: 20px; background: red; }
  .overlap-red-if-too-thick { height: 20px; background: white; position: absolute; top: 1px; width: 100%; }
  .border-test { border-top-style: solid; border-top-width: thin; margin-top: -1px; }
</style>
</head>
<body>
  <p>There should be a black line below and no red.</p>
  <div class=red-if-too-thin></div>
  <div class=cb>
    <div class=border-test></div>
    <div class=red-if-too-thick></div>
    <div class=overlap-red-if-too-thick></div>
  </div>
</body>
</html>
