Homepage has suddenly radically changed

I have been using the firstyme template for over a year and I absolute love it. However, the homepage has suddenly radially changed, and I haven’t done anything! It used to be the homepage looked largely like the interior pages, with a left side nav bar. It’s still correct on the interior pages, but it’s gone on the homepage, as are all my pictures.

Instead, what I get are large blocks of white with simple text on them. The only image is the header image.

To see the problematic page, go here: https://blog.cnbeyer.com
To see a page that works right, go here: https://blog.cnbeyer.com/history/general-history/the-long-long-fall-of-the-roman-empire/

I’ve tried viewing it in multiple browsers.

Again, I haven’t made any changes, so I am at a loss as to what has caused this. I really like this design. No one has made something similar to the best of my knowledge. I really hope you can give me a suggestion on how to correct it (or a similar theme that is still being maintained)

Thanks.