@@ -0,0 +1,31 @@
+<!DOCTYPE html>
+<html lang="en">
+<head>
+ <meta charset="UTF-8">
+ <meta name="viewport" content="width=device-width, initial-scale=1.0">
+ <title>Document</title>
+ <style>
+ * {
+ margin: 0;
+ padding: 0;
+ }
+ html,body {
+ width: 100%;
+ height: 100%;
+ #box {
+ width: 200px;
+ height: 200px;
+ background: #f00;
+ position: absolute;
+ top: 50%;
+ left: 50%;
+ margin-top: -100px;
+ margin-left: -100px;
+ </style>
+</head>
+<body>
+ <div id="box"></div>
+</body>
+</html>
bailing