I noticed that every time you load the page on mise's documentation website, the light theme flashes you for a bit, then your previously saved theme loads. This is a minor issue/annoyance, so I don't think it's productive to flag it as a bug.

I dug around the VitePress documentation and noticed that they already have a solution for this, and you're already using it. So this means that there's something else interfering with it.

Since VitePress's solution is to inject a small JS in a <script> tag to read the theme key stored in the browser's localStorage, I assume Cloudflare's Rocket Loader is deferring it, causing the rest of the content to load first or messing with the ordering that VitePress had determined somehow.

I'm willing to work on a PR for this, but first I'd like to check if it's something that would even be merged, since it's something so minor.