fvim author here.
The font in the screenshot is `Iosevka Slab` which _is_ monospace -- `fvim` currently syncs with the neovim grid system and doesn't support proportional fonts well.
Sorry about the confusion -- I think you've already discovered that (after 46 minutes)!
>The font in the screenshot is `Iosevka Slab` which _is_ monospace -- `fvim` currently syncs with the neovim grid system and doesn't support proportional fonts well.
Aha, looked like a proportional font was used to me. I'd use a more well designed monospace font for the first impression!
In fact, after reading you comment, I promptly startet to install it (still compiling as I type this). My use-case is creative writing: I'm very used to vim keybindings from coding, but prefer to have a variable-width fonts for writing.