Overview
Interactive roadmap grid: bars that contain another roadmap show a nested icon and cyan-forward border. Hover to preview child titles. Click to open a dialog with summary, optional HTML detail, and a read-only mini-map of the next level; use Open nested roadmap to drill in. Move back with Up one level, Reset to root, or any breadcrumb segment.
Data contract
Each level is JSON version 1 with title, columns, tracks, and bars.
A bar is drillable when child is present and child.bars is non-empty.
Optional summary (plain text) and detailHtml (trusted server HTML only) appear in the modal.
Python: render_nested_roadmap(config=…) in
components/nested_roadmap.py. Assets: nested-roadmap.css, nested-roadmap.js.
Live demo
Try Reliability program → Cell architecture for three levels; try Launch track for two levels; compare Hardening window (leaf).