<div class="main">
<div class="left">left</div>
<div class="right">right</div>
</div>
.main {
padding: 10px;
width: 1000px;
background: #aaa;
}
.left {
width: 600px;
height: 200px;
background: #6FB0CC;
}
.right {
width: 300px;
height: 200px;
background: #ABD16C;
}
Also see: Tab Triggers