Interactive Greeting Card Web App

I’m building a colourful, vibrant online greeting card that feels more like a mini-site than a static e-card, and I’d like you to take care of the front-end build. The core stack is plain HTML, CSS and vanilla JavaScript—no frameworks—so the final files can be dropped onto any standard web host and shared by simply sending a URL.

Here’s what I need the finished page to do:
• Pull in a user-defined name and message so every recipient sees something written just for them.
• Open with smooth slide-in effects on each section; no fades or bounces, just tasteful horizontal or vertical slides that look great on both mobile and desktop.
• Fire a lively confetti burst when the card loads (or when a button is pressed—open to your suggestion).
• Present a photo gallery fed by personal images; thumbnails should expand or slide into view without page reloads.
• Offer a couple of interactive buttons/sections—for example “Read Your Message”, “Open Gallery”, “Replay Confetti”—to make the card feel playful.
• Stay fully responsive, loading quickly and rendering perfectly on Chrome, Safari, Firefox and Edge.

Code expectations:
• Keep HTML semantic and minimal.
• Organise CSS with clear section comments and variables for the main theme colours so I can tweak hues easily.
• Encapsulate JavaScript functions to avoid global pollution; comments explaining where to swap the name, message and image URLs are essential.
• No external dependencies other than a lightweight confetti script (if you choose to use one) and any small, self-hosted assets.

Acceptance will be based on:
1. Zero console errors in the latest versions of major browsers.
2. Page weight reasonable for quick sharing—ideally under 1 MB once images are optimised.
3. Smooth, jitter-free slide animations capped at 60 fps on a mid-range phone.
4. Clear instructions (readme or code comments) showing exactly where to edit text, colours and image paths.

If this sounds up your alley, let me know how you’d approach the slide animations and any confetti library you prefer. Looking forward to seeing the card come to life!