<style type="text/css">
.one{width:1000px; height:800px; border:1px solid #FF0000}
.two{width:800px; height:600px; border:1px solid #000000; margin:50px;}
.three{width:700px; height:500px; border:1px solid #CC00FF; margin:50px;}
<style type="text/css">
.one{width:1000px; height:800px; border:1px solid #FF0000}
.two{width:800px; height:600px; border:1px solid #000000; margin:50px;}
.three{width:700px; height:500px; border:1px solid #CC00FF; margin:50px;}