1px（1像素）边框问题

1px（1像素）边框问题

.box{
position: relative;
border: none;
}

.box:after{  //  单边框
content: '';
position: absolute;
bottom: 0;
background: #DCDCDC;
width: 100%;
height: 1px;
-webkit-transform: scaleY(0.5);
transform: scaleY(0.5);
-webkit-transform-origin: 0 0;
transform-origin: 0 0;
}

.box:after{  //   四条边框
content: '';
position: absolute;
top: 0;
left: 0;
border: 1px solid #000;
-webkit-box-sizing: border-box;
box-sizing: border-box;
width: 200%;
height: 200%;
-webkit-transform: scale(0.5);
transform: scale(0.5);
-webkit-transform-origin: left top;
transform-origin: left top;
}