Sidebar problem in Firefox

I used IE while constructing my blog and only recently looked at it in Firefox. In IE everything looks fine, but in Firefox, the sidebar is at the top right, above the text instead of at the left where it is supposed to be.

I already checked the post width including long links and everything. I already checked images, there are not that many anyway. I have already toyed with margins, padding and width of the wrapper, sidebar and content to no avail.

I even tried repositioning the sidebar below the loop instead of above it, but that put my sidebar at the bottom (but at least at the left) in both IE and Firefox.

The sidebar has position relative and is set to float to the left. Position absolute didn’t help.

I validated the blog with W3C and after corrections checked out as valid.

How can I get the sidebar to the right (or for that matter to the left) and the text next to it and not below?

Site: https://www.jamesfive19.com/blog/

You may recognize the subluemenal theme.

It seems like everyone has problems with IE rather than Firefox, but mine are just the opposite. The code seems to react adversely in Firefox.