块级元素与行内元素
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>网页头部</title>
</head>
<body>
<div style="background-color: red;height: 300px; width: 400px">php中文网</div>
<p style="background-color: yellow;height: 100px;width: 400px">欢迎你</p>
<span style="background-color: #ff6500">我是超人</span>
</body>
</html>