Luna — Period & Ovulation

Luna is a simple period tracker for following and predicting your menstrual cycle.
Luna the character greets you with a short message tailored to today's cycle phase, and logging your period start/end takes one tap.

Key features
- Log period start/end and predict your next period and ovulation date
- See period, predicted period, fertile window, and ovulation at a glance on the calendar
- Log daily flow, condition, mood, and symptoms
- Predictions get sharper the more you log (average cycle/period length, delay correction)
- Local reminders for upcoming period/ovulation and daily logging (all on-device, no server)
- Theme-based app icons: Blossom, Mint, Lavender, Midnight, Honey
- Optional 4-digit PIN app lock
- Export/import a backup file (stays on your device unless you choose to share it)

A cycle calendar you can read at a glance
The monthly calendar colours each day so you can see where you are without reading numbers. Past cycles, the predicted next start, your fertile window and the estimated ovulation day all sit on the same screen. Tap any day to open its record, or scroll back through previous months to see how your cycle has changed over time.

Daily logging that takes seconds
Record flow intensity, cramps and other symptoms, your mood, and how you feel that day. Everything is a tap — there are no long forms to fill in. Over time these notes become a private diary of your cycle that you can scroll back through whenever you want.

If your cycle is irregular
Cycles are rarely the same length every month. Luna works from your own logged history rather than a fixed 28-day assumption, so the more you record, the closer the estimates get. When a period arrives late, Luna adjusts the following predictions instead of leaving the calendar out of date. Estimates are based on your own records and are not medical advice.

Reminders you control
Optional reminders can tell you when your next period or fertile window is approaching, and nudge you if you have not logged in a while. Notifications are generated on your device — no server ever sees your schedule — and you can turn any of them off in settings.

Made to be private
Luna works offline. There is no sign-up, no account, and no cloud sync, so nothing about your cycle is tied to an email address or a profile. Add a 4-digit PIN lock if you share your phone, and export a backup file when you want a copy you control.

Privacy principles
- All records are stored only in this device's local storage. Nothing is sent to a server.
- Your period/health records are never used for ad personalization.
- Your data never leaves this device unless you export a backup yourself.

How it's funded
- Free, supported by a bottom banner ad and an occasional card-style ad after logging (max twice a day).
- No interstitial (full-screen, unskippable) ads.