em { color: #f00 } /* #rgb */
em { color: #ff0000 } /* #rrggbb */
em { color: rgb(255,0,0) }
em { color: rgb(100%, 0%, 0%) }
em { color: white }

a {
    background-color: transparent;
    background-color: #f00;
    background-color: #ff0000;
    background-color: rgb(255,0,0);
    background-color: rgb(100%, 0%, 0%);
    background-color: white;

    background-image: url("image.png");
    background-image: none;

    background-repeat: repeat;
    background-repeat: repeat-x;
    background-repeat: repeat-y;
    background-repeat: no-repeat;

    background-attachment: scroll;
    background-attachment: fixed;

    background-position: 10%;
    background-position: 10px;
    background-position: left;
    background-position: center;
    background-position: top;
    background-position: bottom;
    background-position: center;
    background-position: right;
    background-position: right 10%;
    background-position: right 10px;
    background-position: right top;
    background-position: right bottom;
    background-position: right center;

    background: rgb(80%, 10%, 10%) url("image.png") no-repeat fixed left top;
}