[css]hover 될 때 ::after 스타일 변경

    #example li:hover::after{
        opacity:1;
    }
    #example li::after{
        opacity: 0;
        transition-duration: 0.5s;
        content: '';
        width: 82px;
        height: 5px;
        background-color: #fff;
        position: absolute;
        bottom: 0;
        border-radius: 12px 12px 0 0;
        box-shadow: 0px 2px 2px rgb(0 0 0 / 15%);
    }