LazyScar/BiliBili-To-English — reverse-engineered prompt

Build me a browser extension that makes BiliBili usable for people who don’t read Chinese. When someone opens BiliBili, it should translate the page right there, including buttons, menus, video titles, comments, creator pages, and subtitles when they’re watching a video.

I want a simple toolbar popup where the user can pick a language like English, French, Japanese, Russian, or Vietnamese, with a clean look and flag icons if possible. The extension should remember the language they picked so they don’t have to choose it every time.

Use a built in dictionary for common BiliBili words so the interface feels fast, then fall back to online translation for anything unknown. Captions and page text should update automatically as new content loads or changes. Make it work in Chrome style browsers and Firefox if possible, and keep it privacy friendly, with no account or data collection.