:before, :after与 transform

.radius-border{
    position: relative;
}
@media screen and (-webkit-min-device-pixel-ratio: 2){
    .radius-border:before{
        content: "";
        pointer-events: none; /* 防止点击触发 */
        box-sizing: border-box;
        position: absolute;
        width: 200%;
        height: 200%;
        left: 0;
        top: 0;
        border-radius: 8px;
        border:1px solid #999;
        -webkit-transform(scale(0.5));
        -webkit-transform-origin: 0 0;
        transform(scale(0.5));
        transform-origin: 0 0;
    }
}