Full-screen background (IE included)

                                          .content {
    position: relative;
    width: 760px;
    z-index: 10;
}
.background {
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    position: absolute;
    z-index: 2;
}
.portrait {
    height: 100%;
}
.landscape {
    width: 100%;
}
.full {
    width: 100%;
    height: 100%;
}