ProgrammerGaurav/happy-birthday ? reverse-engineered prompt

Build me a simple happy birthday website that opens with a big cheerful birthday greeting and a place for the person’s name, like it can say Happy Birthday Gaurav when the name is in the link. I want it to feel festive and playful, with nice colors, animated text or decorations, and background music that plays with the page.

Make it a single page experience that works in a browser, using plain HTML, CSS, and JavaScript. It should look good on desktop and phone, and it should be easy to change the name in the URL or on the page. If you need to, look up current browser friendly ways to handle audio and simple animations online.

Keep the design warm and celebratory, with a birthday card style layout, a few visual effects like confetti or balloons if that fits, and a polished finish so I can open it and share it right away.