<div class="g-bd2 f-cb">
    <div class="g-mn2">
        <div class="g-mn2c">
            <p class="red">左侧自适应</p>
        </div>
    </div>
    <div class="g-sd2">
        <p class="green">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;}

/* 两列左侧自适应布局 */
.g-bd2{margin:0 0 10px;}
.g-sd2{position:relative;float:right;width:230px;margin-left:-230px}
.g-mn2{float:left;width:100%;;}
.g-mn2c{margin-right:240px;}