Since you're on Firefox, may I suggest using vertical/tree/nested tabs at the side of the Firefox window?
"Tree Style Tab" is the extension I use. Here's a quick screenshot showing its organizational capabilities: https://imgur.com/gallery/wsHSfSt
Mine uses a user style CSS so looks a little different to the default install, but I highly recommend it! If you want to see my CSS, I can share it, just let me know!
I do use Tree Style Tab. That and Vimperator are what keep me on Firefox - well that and the fact that I don't want to see another browser monopoly. But thank you for suggesting it, TST is a wonderful tool.
"Tree Style Tab" is the extension I use. Here's a quick screenshot showing its organizational capabilities: https://imgur.com/gallery/wsHSfSt
Mine uses a user style CSS so looks a little different to the default install, but I highly recommend it! If you want to see my CSS, I can share it, just let me know!
https://addons.mozilla.org/en-US/firefox/addon/tree-style-ta...
https://github.com/piroor/treestyletab