gistfile1.css

background-image:
    -webkit-gradient(linear, left bottom, left top,
        color-stop(0, #ff0000),
        color-stop(0.166667, #ff00ff),
        color-stop(0.333333, #0000ff),
        color-stop(0.5, #00ffff),
        color-stop(0.666667, #00ff00),
        color-stop(0.833333, #ffff00),
        color-stop(1, #ff0000));