css float布局--右侧上部固定下部自适应大小

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
   <style>
    html,body{
        height:100%;
    }
    .content{
        height:100%;
        background-color: red;
        position: relative;
        z-index: -3
    }
    .right_top{
        height:400px;
        width: 300px;
        background: yellow;
        z-index: 1
    }
    .right_bottom{
        height:100%;
        background-color: violet;
        width: 300px;
        position: absolute;
        right: 0;
        top: 0;
        z-index: -1
    }
    .l{
        float: right;
    }
    .r{
        height: 100%;width: 400px;float: left;
        background: wheat;
    }
   </style>
</head>
<body>
         
    <div class="content">
       <div class="r"></div>
        <div class="l">
            <div class="right_top"></div> 
        </div>
        <div class="right_bottom"></div>
    </div>
    
</body>
<script>
    
 
</script>
</html>