Compass Magick + PhantomJS = ♥

phantom.scss

@import 'compass';

$theme1: red;
$theme2: maroon;

$button_width:  320px;
$button_height: 24px;

a {
  background: #fff magick-sprite('button', magick-phantom($button_width, $button_height,
    $background-image: "-webkit-gradient(linear, left top, left bottom, from(#{$theme1}), to(#{$theme2}))",
    $border: 1px solid $theme2,
    $border-radius: 5px,
    $box-shadow: 0 2px 4px rgba(0, 0, 0, 0.25)
  ));
  display: block;
  width: $button_width;
  line-height: $button_height;
  text-align: center;
}