How to revert GitHub's new interface design to the previous version?

I am not a fan of the latest UI changes that GitHub introduced. The new design has odd borders on every section, making it look cluttered and unattractive. The former layout was much neater and easier to navigate. I’ve looked through the settings, but I can’t seem to find an option to go back to the old interface. Does anyone know if there’s a way to switch to the classic GitHub appearance? Perhaps there’s a browser extension or a hidden option that I haven’t noticed? I use GitHub extensively for my work, and this new design is really frustrating. I would be grateful for any assistance!

sad to say but github removed the old ui option. but you could check out “GitHub Web IDE” ext… or use stylus to apply old themes from userstyles.org. some cool devs share their themes there.