As for the stack: it's built mostly with Django, htmx and Tailwind CSS. It uses a SQLite database, and is hosted (for free) at Fly. The characters' graphics come from the open source game Battle For Wesnoth.
I'm afraid my skills in terms of design are rather suboptimal, so the quality of the design is... well, let's just say it's playable ahah
The whole thing is open source: https://github.com/olivierphi/zakuchess#readme Apart from the source code itself, the repo's README also gives a bit more details about the various packages I used.
1. htmx: https://htmx.org/