如图，请问用css怎么实现？或者用别的办法实现？谢谢。
<!doctype html>
<html>
<head>
<title></title>
<style>
div
{
亩历茄 height: 200px;
border: 0;
}
.clear:after
迅察 {
content: '20';
clear: both;
display: block;
}
.left
{
width: 150px;
float: left;
background-color: Yellow;
}
.content
{
margin-left: 150px;
烂备display: block;
position: relative;
}
.content div
{
width: 50%;
}
</style>
</head>
<body>
<div class="clear">
<div class="left">
左
</div>
<div class="content clear">
<div style="background-color: Red; float: left;">
</div>
<div style="background-color: Black; margin-left: 50%;">
</div>
</div>
</div>
</body>
</html>
使用百分比