anuj0224/binary-world ? reverse-engineered prompt

Build me a simple, clean binary conversion web tool called Binary World.

I want one page where someone can quickly convert decimal to binary, binary to decimal, text to binary, and binary to text. It should be easy to use, work fully in the browser, and feel fast and lightweight. Please make the layout responsive so it looks good on desktop, tablet, and mobile, with a minimal modern style.

Add clear input validation so bad input gets a friendly message instead of confusing results. Make the interface straightforward, with a place to enter text, a way to choose the conversion, and an obvious result area. It should all be done with plain HTML, CSS, and JavaScript, no frameworks or backend needed.

If you need to look up any current browser behavior or best practices, go ahead and check online.