1px的实现

<!DOCTYPE html>  
<html>  
    <head>  
        <meta charset="UTF-8">  
        <title></title>  
        <meta name="viewport" content="width=device-width,initial-scale=1,minimum-scale=1,maximum-scale=1,user-scalable=no" />  
        <style type="text/css">  
            .border{  
                position: relative;  
            }  
            .border::after{  
                display: block;  
                position: absolute;  
                left: 0;  
                bottom: 0;  
                 100%;  
                border-top:1px solid rgba(7,17,27,0.1);  
                content: " ";  
            }  
            @meta (-webkit-min-device-pixel-ratio:1.5),(min-device-pixel-ratio:1.5){  
                .border-1px::after{  
                    -webkit-transform: scaleY(0.7);  
                    transform:scaleY(0.7)  
                }     
            }  
            @meta (-webkit-min-device-pixel-ratio:2),(min-device-pixel-ratio:2){  
                .border-1px::after{  
                    -webkit-transform: scaleY(0.5);  
                    transform:scaleY(0.5)  
                }     
            }  
        </style>  
    </head>  
    <body>  
        1px像素的实现  
        <div class="border border-1px">  
  
        </div>  
    </body>  
</html>