<div class="g-bd4 f-cb">
    <div class="g-mn4">
        <div class="g-mn4c">
            <p class="red">左侧自适应</p>
        </div>
    </div>
    <div class="g-sd41">
        <p class="green">右侧定宽</p>
    </div>
    <div class="g-sd42">
        <p class="blue">右侧定宽</p>
    </div>
</div>

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

/* 三列左侧自适应布局 */
.g-bd4{margin:0 0 10px;}
.g-sd41,.g-sd42{position:relative;float:right;width:160px;}
.g-sd41{width:200px;margin-left:10px;}
.g-mn4{float:left;width:100%;margin-right:-370px;}
.g-mn4c{margin-right:380px;}