<!DOCTYPE html>
<html>
<head>
<title>My website.</title>
</head>
<body>
<div><h1>Welcome!<h1></div>
<div>This is my website.</div>
<div>This is my website.<div>
<button CLASS='BUTTON' id="button_1">我是按钮一号</button>
<button CLASS='BUTTON' id="button_2">我是按钮二号</button>
<body>
<html>
div{
background-color:pink;
}
.BUTTON{
color:darkgreen;
}
#button_2{
font-weight:bold;
}