W3Schools Tryit 编辑器 - W3Schools 中文教程

<!DOCTYPE html>
<html>
<head>
<meta name="viewport" content="width=device-width, initial-scale=1">
<style>
/* The device with borders */
.smartphone {
  position: relative;
  width: 360px;
  height: 640px;
  margin: auto;
  border: 16px black solid;
  border-top-width: 60px;
  border-bottom-width: 60px;
  border-radius: 36px;
}

/* The horizontal line on the top of the device */
.smartphone:before {
  content: '';
  display: block;
  width: 60px;
  height: 5px;
  position: absolute;
  top: -30px;
  left: 50%;
  transform: translate(-50%, -50%);
  background: #333;
  border-radius: 10px;
}

/* The circle on the bottom of the device */
.smartphone:after {
  content: '';
  display: block;
  width: 35px;
  height: 35px;
  position: absolute;
  left: 50%;
  bottom: -65px;
  transform: translate(-50%, -50%);
  background: #333;
  border-radius: 50%;
}

/* The screen (or content) of the device */
.smartphone .content {
  width: 360px;
  height: 640px;
  background: white;
}
</style>
</head>
<body>

</body>
</html>