<!DOCTYPE html><html><head><meta charset="utf-8"> <title>菜鸟教程(runoob.com)</title> <style> div{ width:100px; height:100px; border:1px solid black; position: absolute; top: 50%; left: 50%; transform: translate(-50%,-50%); /* Rotate div */}</style></head><body><div>Hello</div></body></html>
