css-box-shadow

.arti_type_shadow {
    position: absolute;
    width: 100%;
    height: 6px;
    left:;
    right:;
    background-image: url(http://images2017.cnblogs.com/blog/908704/201709/908704-20170911094758735-938314135.png);
    background-repeat: repeat-x;
}