Floated content breaks other floats on the page - css

Question

I'm working on the "About Us" header on this page
Basically the little div there with the images and blue "About Us" block was an image, but for SEO purposes, I'm now replacing it with a structure that can use an <h1>...</h1> tag.
As you can see, the layout of the images and header tag works perfectly, but it's pushed the right column of the page in under the content.
I've checked, and double-checked and it looks like all floats are properly contained (unless I missed something) so I'm not sure how to fix this.
Can anyone tell me what I'm doing wrong here?
The HTML:
<div class="page_header">
<div>
<img src="http://sela.netgendns.co.za/wp-content/uploads/2012/11/sela-about-us-1.jpg">
<img src="http://sela.netgendns.co.za/wp-content/uploads/2012/11/sela-about-us-2.jpg" alt="" />
<img src="http://sela.netgendns.co.za/wp-content/uploads/2012/11/sela-about-us-3.jpg" alt="" />
<h1>About Us</h1>
</div>
</div>
The CSS:
/* Page Headers
----------------------------*/
.page_header div {
overflow: hidden;
min-width: 665px;
}
.page_header img, .page_header h1 {
float: left;
margin: 10px 10px 0 0;
}
.page_header img:nth-child(2) {
clear:right;
}
.page_header h1.about-us {
line-height: 90px;
background: #00f;
color: #fff;
padding: 0 42px;
}
Thanks in advance!

Answer 1

Hey Ortund Actually wrote a HTML markup in bit of improper way so you should write like this :-
<div id="main">
<div id="content">
<div id="sidebar-primary">
</div>
see the attached image its working fine through this method :-

Answer 2

That is because your <div id="sidebar-parimary"> should reside inside the <div id="main"> element.
Currently it is:
<div id="main">
<div id="content">...</div>
</div>
<div id="sidebar-primary">..</div>
it should be:
<div id="main">
<div id="content">...</div>
<div id="sidebar-primary">..</div>
</div>