<!DOCTYPE html>
<html>
<head>
<style>
form { display: block;
margin-top: 0em;
}
</style>
</head>
<body>
<p>一个 form 元素显示如下：</p>
<form action="demo_form.asp">
First name: <input type="text" name="FirstName" value="Mickey"><br>
Last name: <input type="text" name="LastName" value="Mouse"><br>
<input type="submit" value="提交">
</form>
<p>一个自定义的表单元素（更改了 margin-top）：</p>
<form action="demo_form.asp" style="margin-top:50px;">
First name: <input type="text" name="FirstName" value="Mickey"><br>
Last name: <input type="text" name="LastName" value="Mouse"><br>
<input type="submit" value="提交">
</form>
</body>
</html>