Vireo

Style: flat, dark theme, deep teal-black canvas, rose-pink cycle markers, blue fertile-window dots, bold sans headline.

Layout: full-screen drag-select calendar spanning multiple months with a bottom legend bar.

Components: multi-month day grid, cycle-days/fertile-window/predicted legend, drag-to-select range highlight, clear/confirm buttons.

Vibe: intimate, empowering, women's health tracker.