body{
            background:yellow;
        }
        .c1{
            height:90px;
            background:rgba(255,0,0, .3);
            /* background:url(./test.png); */
        }
        .c2{
            height:90px;
            /* background: -webkit-linear-gradient(left, red, green); */
            /* background: linear-gradient(to right, red, green); */
            /* background: linear-gradient(180deg, red, green); */
            /* background: linear-gradient(135deg, red 0, green 10%, yellow 50%, blue 100%); */
            background: linear-gradient(135deg, transparent 0, transparent 49.5%, green 49.5%, green 50.5%, transparent 50.5%, transparent 100%),
                linear-gradient(45deg, transparent 0, transparent 49.5%, red 49.5%, red 50.5%, transparent 50.5%, transparent 100%);
            background-size: 30px 30px;
        }