边框渐变色

    border-bottom: 1px solid;
    border-image: -webkit-linear-gradient(#F80, #2ED) 20 20;
    border-image: -moz-linear-gradient(#F80, #2ED) 20 20;
    border-image: -o-linear-gradient(#F80, #2ED) 20 20;
    border-image: linear-gradient(to right, #F80, #2ED) 1;