explain

# explain Resolve all bundled paths from this SKILL.md file, never from a hard-coded agent installation directory. The plugin root is two directories above this skill. The complete `yes` plugin is the supported installation unit. Write and revise local source files. Deliver a single self-contained HTML file by default, or an HTML + assets bundle when requested. Keep essential viewing features usable without network access or persistent storage. Do not upload, publish, or change visibility unless requested. Review the actual rendered output on desktop and mobile; report unavailable checks honestly. Before writing content, plan it with the sibling `design` skill: write `learning-brief.md`, or reuse the one a course has already written. Follow the brief's learner, objectives and sequence. Where the brief leaves the order open, open on the concrete problem, name the parts the mechanism uses, then walk a small worked example through the mechanism and its trade-offs. Distinguish sourced facts from assumptions and include source links near claims. Create `explanation.html` with inline CSS and JavaScript. Use system fonts and inline SVG or embedded images; do not depend on a CDN. Use semantic sections, readable text, visible focus indicators, and controls with accessible labels. Add interaction only when changing a value or revealing a step aids understanding. Give each section the brief's thinking point: a question or prediction the reader attempts before the answer is revealed. End with questions answered unaided, not a recap. For a user-stepped presentation use the sibling `slides` skill. For narration use `video`; for two-character narration use `zundamon-video`; for assessment use `quiz`; for multiple lessons use `course`. These are choices of output format, not mandatory steps for an ordinary explanation. Give each Japanese term of art one form ([terms](../../references/terms-ja.md)). Check the explanation against the sources, then render it at desktop and phone widths (`uv run <plugin>/scripts/check_mobile.py explanation.html` lists anything that makes a phone scroll sideways). Test the controls, keyboard focus, and absence of external resource requests. Return the file and say which checks you completed.