Show HN: web-based tax sheet I've been using for the past 3 years

I built this project to help pay estimated tax. This is useful when I trade stocks that result in unplanned capital gain or income. Before this project, I got myself into tax penalty because I underpaid my estimated tax.

You can probably get the same functionality from Excel, but I think the numbers are more readable when rendered with minimum HTML + CSS.

Sharing it for other hackers who'd like to do their own tax <3