1.padding-top:如果是整数表示div内部增加了边距.
<!DOCTYPE html>
<html>
<head lang="en">
<meta charset="UTF-8">
<title></title>
</head>
<body>
<div style="background-color: green;height: 30px;margin-top: 3px;padding-top: 2px"></div>
<div style="height:70px;border: 1px solid red;"></div>
<div style="height: 100px;border: 1px solid yellow">
<div style="margin-top: 10px;margin-left: 10px;background-color: red">
<input>
<input>
<input>
</div>
</div>
<div style="height: 100px;border: 1px solid red">
<div style="padding-top: 10px;padding-left: 10px;background-color: red">
<input>
<input>
<input>
</div>
</div>
<div style="height: 100px;border: 1px solid red">
<div style="background-color: red">
<input>
<input>
<input>
</div>
</div>
</body>
</html>