<html>
<head>
<style>
html {
    height: 2000px;
    overflow: hidden;
    background-image:
          linear-gradient(blue, blue 10px, green 10px, green 490px, black 490px, black)
        , linear-gradient(blue, blue 10px, green 10px, green 490px, black 490px, black)
        , linear-gradient(blue, blue 10px, green 10px, green 490px, black 490px, black);
    background-attachment: fixed;
    background-size: 200px 500px;
    background-position: left bottom, 200px center, 400px top;
    background-repeat: no-repeat;
}

</style>
<script>
function runTest() {
    if (window.internals)
        window.internals.setTopContentInset(100);
}
window.addEventListener('load', runTest, false);
</script>
</head>
<body>
</body>
</html>