摘要：
<!DOCTYPE html> <html lang="zh"> <head> <meta charset="UTF-8" /> <meta name="viewport" content="width=device-width, initial-scale=1.0" /> <meta http-equiv="X-UA-Compatible" content="ie=edge" /> <title 阅读全文
摘要：
<!DOCTYPE html> <html> <head> <meta charset="UTF-8"> <title></title> <style type="text/css"> .box{ width: 200px; height: 200px; background-color: #0ff; position: absolute; left: 0; top:0; } </style> < 阅读全文
摘要：
代码如下 <!DOCTYPE html><html lang="en"><head> <meta charset="UTF-8"> <title>Title</title> <style> *{ margin: 0; padding: 0; box-sizing: border-box; } .bo 阅读全文
摘要：
代码如下 阅读全文