CountDown MD3 is a countdown planner built with React. Users can create events with a title, date, optional note, and category (General, Work, Personal, Birthday, Holiday, Health). The home screen shows days remaining or days passed, supports optional real-time hour/minute/second display per event, and provides quick search. Events can be pinned, marked as favorites, filtered by tab, and sorted by pin/date priority.
The app stores data locally in browser storage and includes backup tools in Settings: export all events to JSON and import JSON backups. Users can customize appearance with light/dark/system mode, theme color presets, custom color picking, and compact layout mode.
AI features are implemented through the Gemini SDK: suggested events, short motivational quotes for selected events, and optional AI-generated poster backgrounds. The app can render share posters in multiple aspect ratios (1:1, 3:4, 4:3, 9:16, 16:9) and export them as PNG images using html2canvas. The current source shows no account login, cloud sync, ads SDK, payment SDK, or geolocation SDK.