Build a Tech Guide

Create a comprehensive tech guide for $ARGUMENTS.

Follow the full conventions in techguides/CLAUDE.md. The guide must be self-contained HTML with inline CSS, Google Fonts only, 1500-4000+ lines, 8-12 numbered sections, sticky jump nav, and responsive design.

Phase 0 — Plan (interactive)

1. Parse the argument: the first word is the topic (e.g., "xterm.js"), optional second word is the style name (e.g., "celtic").
2. If no style was specified:
   • Read the Style Guide Catalog table in README.md to see which styles are available (empty Tech Guide column) vs already used
   • Suggest 3-4 unused styles that thematically fit the topic
   • Ask the user to pick one
3. Read the chosen style's HTML file from styles/{name}.html to extract the design system (CSS variables, fonts, color palette, component patterns).
4. Read techguides/CLAUDE.md for the template and conventions.
5. Read 1-2 existing tech guides (like python.html or docker.html) to match structure and depth — just skim the first ~100 lines for structure reference.
6. Propose a section outline (8-12 sections) and discuss with the user before proceeding.

Phase 1 — Research (parallel Sonnet subagents)