How do I show two Jekyll blogs on one domain?

So, here’s what I figured out from the replies here (thanks!), a lot of stackoverflowing, and a lot of trial and error.

If you want to pipe two repos (for example, foo and bar) to one website, there are three ways to do it:

  1. Move one repo inside the the other one as a folder, so you have foo and foo/bar. Then ‘call’ each folder to a different url in the website, for example, foo → mydomain.com/ and foo/bar → mydomain.com/bar. I didn’t actually try this because it would be huge folders in my case, a maintenance nightmare, and there would be possible conflicts with competing index pages, config files, css, etc.

  2. Submodules. Retain the repos foo and bar, but set up bar as a submodule inside foo. I didn’t actually try this way because it seems to be a maintenance headache afterwards, and tricky to push the correct repo updates.

  3. Subdomains. Rename foo repo to my-github-name.github.io, retain the bar repo. Custom domain my-github-name.github.iomydomain.com. Set up the subdomain bar.mydomain.com and custom domain bar → bar.mydomain.com. This works pretty much out of the box.

So in my case I have:

jimken123/jimken123.github.io → https://mananamanana.com
jimken123/ohpiglet → https://ohpiglet.mananamanana.com
jimken123/dublinopinion → https://dublinopinion.mananamanana.com
…etc…

Now to figure out the remaining problem of _posts ignoring css…