Takie coś kiedyś wygenerowałem moim programem do tworzenia gradientów:
<h2 style="color:#fff; margin:0; padding:1em; border-bottom:1px solid #888; background-image: -moz-linear-gradient(right, #663300 0%, #cc9900 10%, #ffff00 20%, #ffff99 30%, #ffffcc 40%, #ffffff 50%, #ccccff 60%, #99ccff 69%, #3366ff 80%, #3333ff 90%, #000066 100%); background-image: -o-linear-gradient(right, #663300 0%, #cc9900 10%, #ffff00 20%, #ffff99 30%, #ffffcc 40%, #ffffff 50%, #ccccff 60%, #99ccff 69%, #3366ff 80%, #3333ff 90%, #000066 100%);">Gradient are based on the color palette</h2>
Działać powinno poprawnie na FireFox-ie i Operze.