Show HN: Schengen Zone Travel Day Calculator

I built a small tool to help people traveling to Europe keep track or calculate how many days they will be in the Schengen Zone countries and - assuming they are restricted by the "90 days in a 180-day window" - how many travel days they have used and have remaining.

It's not 100% but I used ChatGPT to help me get it functional in a few hours and it's been the first thing in months I've pushed live so it felt like a win.

Would love feedback from anyone that knows the Schengen Visa 90/180 limits on how I could improve it a bit as I will eventually build it into a larger Europe Travel App I have been building forever.

Things I still need to do:

1. Add Text describing the Schengen Visa requirements, limitis, and included countries.

2. Fix A couple edge cases where the calculation fails slightly.

3. Add a disclaimer that this is for planning purposes only and users should consult official docs/country channels

4. List of Nationalities/Passports that this specific tool actually is for