HTML5 vs Div tag for auto resizing

I hope for a solution, but in the worst case, an explanation of why my div is not resizing, and maybe because I use the nav tag.

I have the following html. When the content in the "section" tag grows, so does the div with the page content class. However, when my navigation menu items increase, the div does not change.

<div class="page-content">
    <nav>
      <ul>{menu items here}</ul>
    </nav>
    <section id="main">
        {bunch of text here}
    </section>
</div>

Here is my css.

.page-content 
{
    display: block;
    position:relative;
    width: 100%;
   margin-left: auto;
    margin-right: auto;
    background-image: url(images/bg-home-main.jpg);
    background-repeat: no-repeat;
    background-position: center;

}

    nav {
    display: block;
    float: left;
    padding: 15px;
    position: relative;
    margin: 0px 0px 0px -45px;
}

#main {
    padding: 5px 25px 5px 25px;
    margin-left: 175px;
}

, div , , . , ( ), , div , . , , div .

+5
1

, , . : ; .

overflow: hidden; clearfix - , , . , : auto Mac ( , - ) : , . IE , . , - , , , , - div , , , : after , , .

+5

All Articles