小三角

{
    border-color: transparent;
    border-right-color: #e5e5e5;
    border-width: 7px;
    margin-top: -7px;
    right: 100%;
    top: 20px;
    border: solid transparent;
    content: " ";
    height: 0;
    width: 0;
    position: absolute;
    pointer-events: none;
}