Simplification for table header generated-content arrow

Created by: necolas

The existing code contains some unnecessary styles and you can't include HTML entities (i.e. ↓) as values of the content property. The block below will do the same thing. You should probably consider dropping the tags from the selectors too.

.zebra-striped .header:after {
  content: "";
  float: right;
  margin-top: 7px;
  border-width: 0 4px 4px;
  border-style: solid;
  border-color: #000 transparent;
  visibility: hidden;
  -webkit-box-shadow: 0 1px 0 #fff;
  -moz-box-shadow: 0 1px 0 #fff;
  box-shadow: 0 1px 0 #fff;
  filter: alpha(opacity=30);
  -khtml-opacity: 0.3;
  -moz-opacity: 0.3;
  opacity: 0.3;
}

Thanks