mdn/learning-area ? reverse-engineered prompt

Build me a simple MDN style learning area site that helps beginners learn web development through small, clear examples.

I want separate sections for HTML, CSS, JavaScript, accessibility, and tools and testing, with each section containing a few working demo pages that match the kind of examples you would see in a learning resource. Keep the pages easy to read, with plain language explanations, sample code, and live examples that show what the code does in the browser. Make it feel organized and educational, so someone can browse by topic and follow along without getting lost.

Please also make the structure easy to maintain, with each topic kept in its own folder, and include a simple README that explains how the learning examples are laid out. If anything useful is missing, look up the current docs online and fill in sensible beginner friendly content.