Overflowing a container div horizontally but not vertically

Question

I\'m working on a website that uses two columns inside a container. The container has a white background that should stretch to the bottom of whichever column is highest, so

Answer 1

The easiest fix in this case seems to be adding <br style="clear:both" /> before the closing tag for #container.

You can change it to <br class="clearfix" /> and .clearfix{clear:both} if you wish.

Answer 2

Solution is to use inline-block elements..

Css

.container{
    width:300px;
    background-color:#ccc;
    margin:0 auto;
    border:1px solid red;
}
.container > div{
    width:150px;
    display:inline-block;
    vertical-align:top;
}
.inner{
    background-color:#666;
    margin-top:10px;
    width:130px;
}
.left .inner{
    margin-left:-10px;
}
.right .inner{
    margin-right:-10px;
    margin-left:auto;
}

HTML

<div class="container">
    <div class="left">
        <div class="inner">left 1st inner panel</div>
        <div class="inner">left 2nd inner panel</div>
    </div><div class="right">
        <div class="inner">right 1st inner panel</div>
        <div class="inner">right 2nd inner panel with arbitrary text to show the increase in parent elements</div>
    </div>
</div>

view demo