checkerboard

body {

    background-image:

    -moz-linear-gradient(45deg, #000 25%, transparent 25%,transparent 75%, #000 75%, #000 100%),

    -moz-linear-gradient(45deg, #000 25%, transparent 25%,transparent 75%, #000 75%, #000 100%);

    background-image:

    -webkit-linear-gradient(45deg, #000 25%, transparent 25%,transparent 75%, #000 75%, #000 100%),

    -webkit-linear-gradient(45deg, #000 25%, transparent 25%,transparent 75%, #000 75%, #000 100%);

    -moz-background-size:100px 100px;

    background-size:100px 100px;

    -webkit-background-size:101px 101px;

    background-position:0 0, 50px 50px;

}