<div class="g-bd3 f-cb">
    <div class="g-sd31">
        <p class="red">左侧定宽</p>
    </div>
    <div class="g-sd32">
        <p class="green">左侧定宽</p>
    </div>
    <div class="g-mn3">
        <div class="g-mn3c">
            <p class="blue">右侧自适应</p>
        </div>
    </div>
</div>

/*base布局块颜色*/
p{height: 150px; padding: 10px; color: #FFF;}
.red{background:red;}
.green{background:green;}
.blue{background:blue;}

/* 三列右侧自适应布局 */
.g-bd3{margin:0 0 10px;}
.g-sd31,.g-sd32{position:relative;float:left;width:200px;}
.g-sd31{width:160px;margin-right:10px;}
.g-mn3{float:right;width:100%;margin-left:-370px;}
.g-mn3c{margin-left:380px;}