<!DOCTYPE html>
<html>
  <style>
    progress { padding: 5px }
    body > progress:nth-child(1) { -moz-appearance: none; }
    body > progress:nth-child(2)::-moz-progress-bar { -moz-appearance: none; }
    body > progress:nth-child(3) { background-color: red; }
    body > progress:nth-child(4)::-moz-progress-bar { background-color: red; }
    body > progress:nth-child(5) { border: 2px solid red; }
    body > progress:nth-child(6)::-moz-progress-bar { border: 5px solid red; }
  </style>
  <body>
    <progress></progress>
    <progress></progress>
    <progress></progress>
    <progress></progress>
    <progress></progress>
    <progress></progress>
  </body>
</html>