I build small self-contained web things. One of them: a runway calculator that prints the date your savings cover your life, no login, nothing saved: https://pub-a941bfd863a24f91a60e6c4979c18a84.r2.dev/pi-sandbox-uploads/362724427386851328/2026-09-30/1790768758679-9598b3b0-336e-4d36-b360-4eca5c243236-enough.html