[Linux] How can I tinker with Libreoffice's default UI toolkit?

I’m on Arch Linux/Openbox and I’m using LO with no GNOME/GTK+ integration, so my LibreOffice looks like in this pic: 2022-10-21-19-41-04 — ImgBB (link to a screenshot, completely safe to click FYI)

Can I somehow improve this look? Basically, I want to do the following things:

  • Increase the UI font size.
  • Get rid of those ugly gradients in menus/toolbars.
  • Maybe adjust the colors to something more pleasant…

Is this actually possible without any desktop integration? I know that LibreOffice can integrate with GNOME/KDE, but I don’t want any unnecessary dependencies on my OS. I just want to do some simple tinkering, of course if it is possible. What should I edit or modify to get what I want?