如图所示:
QQ20180219-222226@2x

使用css伪类before实现

.company-nav-active:before{
    content: ' ';
    display: inline-block;
    width: 12px;
    height: 12px;
    background-color: #0ba360;
    border-radius: 13px;
    position: absolute;
    right: -16px;
    bottom: 44px;
}