月亮_heartbeat
<head>
<meta charset="UTF-8">
<title>
</title>
<style>
body {
background-color: black;
}
div {
width: 100px;
height: 100px;
border-radius: 50%;
background-color: white;
position: absolute;
top: 200px;
left: 200px;
}
</style>
</head>
<body>
<div id="down">
</div>
<div id="center">
</div>
<div id="up">
</div>
</body>
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三種浮動(dòng)
/有效的定位屬性/
position: relative;
/*display
float*/
一
/定位/
position: relative;
二
/*
浮動(dòng) -
從左向右 left;
從右向左 right
*/
float: right;
