I always seem to have this problem with the navigation class in my style.css for each theme where it doesn't seem to clear:both; in my code. Look at this blog post, for example:
http://www.pattyspizza.com/save-five/
See? The navigation and the H2 from the .post is on the same line. I added a <span class="clear"></span> which should've added a clear:both after the navigation class but it didn't. What is the solution for this?
interestingly, giving a height to .navigation (in style.css, near the end) seems to solve your problem:
.navigation {
display: block; height:12px;
text-align: center;
margin-top: 10px;
margin-bottom: 60px;
}
only tested in firefox developer addon.
(deleting your <span class="clear"></span> does not seem to make a difference)
That's really odd. That should just be added by default.
even if (most of) the code is from the default kubrick theme and around for quite a few years, there are still sometimes things that are not as they could be.
just shows, that a theme optimisation is a never-ending job.