Linux Editor Font

I'm switching over from Windows to Linux, and I was able to transfer everything across.

Opening the Calibre ebook editor originally had Consolas as the editor font family, which is not available. So I cleared it, and now it's using a monospace font, but it's relatively large. I wanted to change it, but opening the "Editor font family" preference shows "Choose a font family from the list below" and the list is empty except for the text "None". I'm not sure if this is because it's not using the system Qt, or if this feature is just not available in Linux?

I've attached a screenshot of what I'm seeing when I try to choose a font family.

Attached Thumbnails