移动端1px

<!DOCTYPE html>
<html>

    <head>
        <meta charset="utf-8" />
        <title></title>
        <meta http-equiv="Pragma" content="no-cache" />
        <meta name="viewport" content="width=device-width,initial-scale=1,minimum-scale=1,maximum-scale=1,user-scalable=no" />

        <style type="text/css">
            .onepx-border {
                padding: 30px 0px;
                position: relative;
                background: white;
            }
            
            .onepx-border:before {
                content: '';
                position: absolute;
                top: 0px;
                left: 0px;
                width: 200%;
                height: 200%;
                border: 1px solid blue;
                transform-origin: 0 0;
                transform: scale(0.5, 0.5);
                box-sizing: border-box;
                border-radius: 10px;
            }
            .border{
                margin-top: 10px;
                padding: 30px 0px;
                position: relative;
                border: 1px solid red;
                border-radius: 5px;    /*要变成上面的一半*/
            }
        </style>
    </head>

    <body>
        <div class="onepx-border">
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        </div>
        <div class="border">
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        </div>
    </body>

</html>

先看大名鼎鼎的jquery weUI

<!DOCTYPE html>
<html>

	<head>
		<meta charset="utf-8" />
		<title></title>
		<meta http-equiv="Pragma" content="no-cache" />
		<meta name="viewport" content="width=device-width,initial-scale=1,minimum-scale=1,maximum-scale=1,user-scalable=no" />
		<link rel="stylesheet" href="css/sb.css" />
		<style type="text/css">
			h3 {
				text-align: center;
			}
			
			.sb {
				 90%;
				height: 100px;
				margin: 10px auto;
				border: 1px solid red;
				box-sizing: border-box;
			}
			.sb1 {
				 100%;
				height: 1px;
				margin-top: 50px;
				background: red;
				 
			}
			.main {
				position: absolute;
				box-sizing: border-box;
				 180%;
				height: 200px;
				left: 5%;
				top: 200px;
				transform-origin: 0 0;
				border: 1px solid red;
				transform: scale(.5);
			}
			
			.main1 {
				 100%;
				height: 1px;
				margin-top: 100px;
				background: red;
				transform: scaleY(0.5);
			}
		</style>
	</head>

	<body>
		<h3>原始的</h3>
		<div class="sb">
			<div class="sb1">

			</div>
		</div>
		<h3>缩放后的</h3>
		<div class="main">
			<div class="main1">

			</div>
			
		</div>
	</body>

</html>