<style>
.c1{width:100px;height:100px;position:relative;border:1px #ccc solid}
.d1{width:20px;height:20px;border:1px #ccc solid;font-size:1px;top:80px;left:80px;position: absolute;}
</style>
<body>
<div class="c1">
<div class="d1"></div>
</div>
<style>
.c1{width:100px;height:100px;position:relative;border:1px #ccc solid}
.d1{width:20px;height:20px;border:1px #ccc solid;font-size:1px;top:80px;left:80px;position: absolute;}
</style>
<body>
<div class="c1">
<div class="d1"></div>
</div>