Web & Desktop Lunisolar Calendar

I need a digital lunisolar calendar that accurately aligns lunar months with the solar year. The finished product must work in any modern browser and run as a desktop application (Windows and macOS at minimum; Linux support is a plus), sharing a single code-base so updates roll out everywhere at once.

Core requirement
• Event reminders: users pick a lunisolar date or a standard Gregorian date and receive a pop-up, banner, or system notification at the chosen time. Snooze and dismiss controls are essential.

Future-ready design
Sync with other calendars and visual theme options are not required right now, yet the architecture should leave room to bolt them on without a rewrite.

Deliverables
• Responsive web build (deployed to a test URL)
• Desktop build or installer for each supported OS
• Source code with clear instructions to run locally
• Short user guide explaining how the lunisolar logic works and how to set reminders

Feel free to propose the tech stack—React + Electron, Vue + Tauri, or another approach—as long as it keeps the interface snappy and cross-platform.