CSS Only Zebra Striped PRE Tag

Does not display the stripping in IE. :(

HTML

<pre>
pre {
  display:block;
  max-width: 600px;
  font:normal 12px/22px Monaco,Monospace !important;
  color:#CFDBEC;
  background-color:#2f2f2f;
  background-image:-webkit-repeating-linear-gradient(top, #444 0px, #444 22px, #2f2f2f 22px, #2f2f2f 44px);
  background-image:-moz-repeating-linear-gradient(top, #444 0px, #444 22px, #2f2f2f 22px, #2f2f2f 44px);
  background-image:-ms-repeating-linear-gradient(top, #444 0px, #444 22px, #2f2f2f 22px, #2f2f2f 44px);
  background-image:-o-repeating-linear-gradient(top, #444 0px, #444 22px, #2f2f2f 22px, #2f2f2f 44px);
  background-image:repeating-linear-gradient(top, #444 0px, #444 22px, #2f2f2f 22px, #2f2f2f 44px);
  padding:0em 1em;
  overflow:auto;
  border: 10px #efefef solid;
}
</pre>

CSS

body { margin: 20px; }

pre {
  display:block;
  max-width: 200px; /* Adjust width to suit your needs */
  font:normal 12px/22px Monaco,Monospace !important;
  color:#CFDBEC;
  background-color:#3f3f3f;
  background-image:-webkit-repeating-linear-gradient(top, #444 0px, #444 22px, #2f2f2f 22px, #2f2f2f 44px);
  background-image:-moz-repeating-linear-gradient(top, #444 0px, #444 22px, #2f2f2f 22px, #2f2f2f 44px);
  background-image:-ms-repeating-linear-gradient(top, #444 0px, #444 22px, #2f2f2f 22px, #2f2f2f 44px);
  background-image:-o-repeating-linear-gradient(top, #444 0px, #444 22px, #2f2f2f 22px, #2f2f2f 44px);
  background-image:repeating-linear-gradient(top, #444 0px, #444 22px, #2f2f2f 22px, #2f2f2f 44px);
  padding:0em 1em;
  overflow:auto;
  border: 10px #efefef solid;
}