Schengen 90/180 Calculator: Track EU visa days, avoid €5K fines

Hey Product Hunt! 👋 I built this after nearly getting hit with a €1,200 fine at Barcelona airport for miscounting my Schengen days. The 90/180 rule is deceptively complex - it's NOT just "stay 90 days then leave for 90 days." It's a rolling 180-day window where every single day counts, even short trips from months ago. 🚨 The Problem: - 70M+ UK citizens now subject to this rule post-Brexit - 5M+ digital nomads navigating Europe - Existing calculators are clunky, behind paywalls, or inaccurate - People are getting fined €500-5,000 and banned from Europe ✨ What I Built: - Clean, mobile-first calculator - Track unlimited trips - Visual status (safe/warning/danger zones) - Shows exact reset date - 100% client-side (privacy-first, works offline) - No signup, completely free Built it as a single-page tool with vanilla JS - fast, simple, works everywhere. Would love feedback from fellow travelers and makers! What features would make this more useful? 🦉 Thanks for checking it out!