I'm having a lot of trouble with this, given the following HTML:
<!doctype html>
<head>
<style>
    .nav {
        width: 26%;
        display: inline;
        float: left;
        margin-left: 2%;
        margin-right: 2%;
        background-color: #FF0000;
    }
    .content {
        width: 56%;
        display: inline;
        float: left;
        margin-left: 2%;
        margin-right: 2%;
        background-color: #0000FF;
    }
</style>
</head>
<body>
    <div style="width: 600px;">
        <div class="nav"><p>nav</p></div>
        <div class="content"><p>content</p></div>
    </div>
</body>
</html>
I get the following (expected) output:

However, if I change the div element with the class = nav to this:
<div class="nav"></div>
I get this (not expected and undesirable) output:

It's like there is no div there! How can I get the following output:

Surely there must be a simple way to do this, no?