.tab
border-1px{red}
minxin
border-1px(&color)
position:relative
&::after
display:block
position:absolute
left:0
bottom:0
width:100%
border-top:1px solid $color
content:''
媒体查询解决1移动端像素问题
在添加1px的类加同级类.border-1px
@media (-webkit-min-device-pixel-ratio:1.5),(min-device-pixel-ratio:1.5)
.border-1px
&::after
-webkit-transform:scaleY(0.7)
transfom:scaleY(0.7)
@media (-webkit-min-device-pixel-ratio:2),(min-device-pixel-ratio:2)
.border-1px
&::after
-webkit-transform:scaleY(0.5)
transfom:scaleY(0.5)