fastai/course20 ? reverse-engineered prompt

Build me a website for the Practical Deep Learning for Coders course and book.

I want a clean course site where people can browse the lessons, read the chapter material in interactive notebook form, and jump between the videos, transcripts, and notebook pages easily. The lessons should have searchable transcripts, and the videos should support captions with language switching, including Chinese and Spanish. Make it easy for a beginner to get started with links to recommended hosted notebook options like Colab and a real Jupyter server option, plus a simple way to find setup help and community support.

The site should feel educational and approachable, with a clear home page, navigation for chapters and lessons, and pages for the supporting notebooks, images, and files that go with the course. If you need to look up current docs or best practices for how this kind of site should work, go ahead and do that.