I use vim in a tiling window manager, i3-gaps. I have some aesthetic configuration settings, which do things like alter the opacity of unfocussed windows, change the gaps between windows, and so on. As such, when I have multiple buffers open, I tend to have them open in multiple disconnected windows.
But this has some disadvantages: Each window has a different buffer list; it's hard to close multiple windows simultaneously, and so on. So I would prefer to move back to using vim panes.
But I don't want to give up the aesthetic appeal of the windows 'looking' disjoint, and having nice graphical configuration. To what extent is it possible to configure the graphical appearance of vim panes? I'm particularly interested in how to get the two things I mentioned above: transparent gaps between panes, and variable opacity for unfocussed panes. But I'd be happy to know about other possibilities.