I need to get up to speed with shadcn (ugh, react *and* tailwind) for $dayjob so I used that as an excuse for a long-overdue rewrite of my old app for visualizing diatonic chords for a given scale
it's powered by the tonal library which means it has a *ton* of scales (vs just major/minor)
also it's a single-file static app; you can save the HTML file and use it locally