A standalone interactive lesson page for Rize's Differential Equations course (catalog code MATHS X). No login and no backend; progress is saved in the browser's own localStorage.
Live: https://rizecomputerscience.github.io/diffeq1-practice-unit-01/
Source: projects/coursedev/DIFFEQ-I/interactive/pages/practice-unit-01/ on Samuel's machine (SPEC.md the spec and build notes, src/ the source, build.py the build). index.html here is the built page, unchanged. It defines window.__selfCheck() for Rize's page-health monitor (swachtel-dev/rize-interactive-health).