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