mysterious <p> tag aka margins are driving me crazy

Hi everybody,

Here I am again a problem that causes nightmares to all of us newbies: alignment.

I simply can’t get my site perfectly aligned through all the pages. The TOP margin shifts whether I change pages and categories.

Here is the site: http://fot.lucascorato.com

If you note the top margin you will see that the slideshow is well aligned to the logo on the sidebar:

http://www.lucascorato.com/arquivo/01.png

BUT if you go to another page, or category, like 3060º VR Photography, you will see that there is a new space there:

http://www.lucascorato.com/arquivo/02.png

Put side by side (two screen halves with one mirrored to emphasize the difference): http://www.lucascorato.com/arquivo/03.png

A fellow blogger in another forum kindly helped me finding out that a <p> tag comes out at the problematic pages, as you can see in these images he uplaoded:

http://subefotos.com/ver/?302fd5779075a747153fcebf53828e7ao.jpg
http://subefotos.com/ver/?0c9e86ceac476c8ce5e51ed775486e7ao.jpg

On both, the structure is theoretically the same: all of them are single posts, stripped down to only their contents (without titles, time, comments, etc etc). The only difference is that the slideshow is a nextGEN plugin with a Monoslideshow swf, so the only thing in the post is [monoslideshow id=1 w=100% h=600 preset=custom]; on the others I use ordinary text and ordinary html tags between < >, always in html mode on WP dashboard.

I have developed a workaround, which was to create a <h4> in the style.css which has font-height of 1.0em (same as the troubling difference) and insert a <h4> </h4> <br/> line before the plugin tag, bringing everything down. The same line is then used before the logo on the custom menu, also bringing it down. It works, but I don’t think it’s the best way to solve the problem.

Well, if you have had the patience to read all of my long text I really appreciate that and I guess you’re interested in helping me!

Thanks a lot for your time!