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.

首先，在 react.dev 较大的文档页面上使用 Safari 17.2.1 重现所报告的行为，利用链接的录制内容，并将其与 Chrome 和旧版网站进行比较。当加载缓慢和 Safari 滚动时闪烁的问题得到解决或被明确隔离，并且已在所报告的浏览器中检查该行为时，即视为完成。