Slow load times and flickering in Safari

I've been going through the react.dev docs and noticed that they feel sluggish:

https://github.com/reactjs/react.dev/assets/513444/0679274a-9325-4975-afea-b7e5315cffc2

I still see a little bit of flickering on Chrome, but I wouldn't consider it problematic there:

https://github.com/reactjs/react.dev/assets/513444/d1faca05-2606-4bf0-b680-c9f67e2b9fdf

The new site has a lot of interactive elements so it's not fair to compare it with the legacy site, but legacy is an order of magnitude faster:

https://github.com/reactjs/react.dev/assets/513444/fabe323d-e3d4-44d1-b5b7-f42bdcdabfa7

I think there are two separate issues:

• Some (larger) pages take several seconds to load
• Scrolling in Safari makes the screen flicker

This is on Safari Version 17.2.1 (19617.1.17.11.12) on Sonoma 14.2.1 (23C71). 2,6 GHz 6-Core Intel Core i7 MacBook Pro 16. Let me know if you need any other information to help debug.

Inizia riproducendo il comportamento segnalato in Safari 17.2.1 sulle pagine di documentazione più estese di react.dev, utilizzando le registrazioni collegate e confrontandolo con Chrome e il sito legacy. Il lavoro sarà considerato completato quando i caricamenti lenti e lo sfarfallio durante lo scorrimento in Safari saranno risolti o chiaramente isolati, e il comportamento sarà stato verificato nei browser indicati.