Theoretically it should be possible to make child elements flow vertically instead of horizontally, by setting these properties on the parent: display: flex; flex-direction: column;. I tried that with a bunch of the tab elements and it didn’t work. The problem with addons like TST is that they glitch out sometimes, and you have to wait for the tabs to load, it takes much longer on my M1 Mac once I have 100s of tabs open (don’t judge me).
It’s not super tricky to just make tabs flow vertically. This can bee done pretty easily
But behavior is where things start to fall apart. For starters, tabs can’t be dragged to reorder them (well they can, it just doesn’t work). And you can’t do any kind of tree like layout so it’s just a flat vertical list.
If Vertical tabs is your thing, extensions just do it much better.
Oh shit, where did u find that photo? Could I see the CSS so I could try to figure it out?