css箭头

.aui-list-item-arrow:before {
    content: '';
    width: 0.4rem;
    height: 0.4rem;
    position: absolute;
    top: 50%;
    right: 0.75rem;
    margin-top: -0.2rem;
    background: transparent;
    border: 1px solid #dddddd;
    border-top: none;
    border-right: none;
    z-index: 2;
    -webkit-border-radius: 0;
            border-radius: 0;
    -webkit-transform: rotate(-135deg);
            transform: rotate(-135deg);
}