0.5px 细边框

.thin-border{
        position: relative;
        width:200px;
        height:100px;
}
.thin-border:after{
        position: absolute;
        content: "";
        left: 0;
        bottom: 0;
        background: #39BB97;
        width: 100%;
        height:1px;
        transform: scaleY(0.5);
        transform-origin: 0 0;
}