css实现的三角，带边框:

<div id="copy-link">
    <div id="copy-button">
        <div class="copy-box">
            Copy Link
            <div class="triangle"></div>
            <div class="triangle-border"></div>
        </div>
    </div>
</div>

#copy-button{
        display: none;
        color: #000;
        position: absolute;
        left: 50%;
        transform: translateX(-50%);
        bottom: -70px;
        border: none;
        border-radius: 5px;
        box-shadow: 0 0 10px 6px rgb(0 0 0 / 10%);
        z-index: 3;
        background-color: #fff;
}
#copy-link:hover #copy-button{
    display: block;
}

.copy-box{
    box-sizing: border-box;
    width: 203px;
    height: 37px;
    padding: 8px;
    margin: 10px 14px;
    font-weight: normal;
    border: 1px solid #1a8d8d;
    border-radius: 4px;
    color: #1a8d8d;
    font-size: 14px;
}
.triangle {
    width: 0;
    height: 0;
    border-left: 10px solid transparent;
    border-right: 10px solid transparent;
    border-bottom: 10px solid #cecece;
    position: absolute;
    top: -10px;
    left: 50%;
    transform: translateX(-50%);
}
.triangle-border{
    position: absolute;
    top: -16px;
    left: 50%;
    transform: translate(-50%,0);
    border-left: 8px solid transparent;
    border-right: 8px solid transparent;
    border-top: 8px solid transparent;
    border-bottom: 8px solid #fff;
}