First app I shipped was built using HyperCard. Calculated shipping costs for a Homebrew kit seller. Popstack.ai reminds me of HyperCard @scottw https://arstechnica.com/gadgets/2019/05/25-years-of-hypercard-the-missing-link-to-the-web/#:~:text=%22Simply%20put%2C%20HyperCard%20is%20a,knew%20what%20Netscape%20was%20for.
Loved HyperCard. I never got great at HyperScript, but I did figure out how to play midi notes.