---
id: S02
parent: M005
milestone: M005
provides:
  - 2-column technique page layout with 22rem sidebar containing key moments, signal chains, plugins, and related techniques
requires:
  []
affects:
  - S03
key_files:
  - frontend/src/App.css
  - frontend/src/pages/TechniquePage.tsx
key_decisions:
  - Sidebar fixed at 22rem width with sticky positioning at 1.5rem from top
  - Page max-width widened from 48rem to 64rem to accommodate sidebar
  - 768px breakpoint for responsive collapse aligns with existing mobile styles
patterns_established:
  - CSS grid 2-column layout pattern: 1fr + fixed sidebar with sticky positioning and responsive collapse
observability_surfaces:
  - none
drill_down_paths:
  - .gsd/milestones/M005/slices/S02/tasks/T01-SUMMARY.md
duration: ""
verification_result: passed
completed_at: 2026-03-30T08:49:31.884Z
blocker_discovered: false
---

# S02: Technique Page 2-Column Layout

**Technique pages now display prose content (summary + study guide) in a left column and sidebar content (key moments, signal chains, plugins, related techniques) in a right column at desktop widths, collapsing to single column on mobile.**

## What Happened

This slice restructured the technique page from a single-column flow to a 2-column CSS grid layout. The .technique-page max-width was widened from 48rem to 64rem to accommodate the sidebar. A new .technique-columns grid wrapper splits content into a 1fr main column and 22rem sidebar column with 2rem gap. The sidebar uses sticky positioning (top: 1.5rem) so navigation aids remain visible while scrolling long prose. At ≤768px the grid collapses to a single column with static positioning, preserving the existing mobile experience.

In TechniquePage.tsx, the content below the header/report-modal was wrapped in the grid container. The main column contains the Summary section and Body Sections (study guide prose). The sidebar column contains Key Moments, Signal Chains, Plugins, and Related Techniques. The header and report modal remain above the grid at full width.

All new CSS uses only structural properties (grid, gap, positioning) with no hardcoded colors, staying consistent with the existing custom property system. TypeScript compilation and production build both pass cleanly. The Docker web container was rebuilt and restarted on ub01.

## Verification

TypeScript compilation (tsc --noEmit) passed with zero errors. Production build (npm run build) succeeded — 46 modules, 658ms. Docker web container (chrysopedia-web-8096) rebuilt, restarted, and healthy. Browser verification confirmed 2-column layout at desktop width and single-column collapse at 375px mobile width. No hardcoded colors in new CSS rules. All plan must-haves satisfied.

## Requirements Advanced

- R006 — Technique page now has structured 2-column layout separating prose from reference material, improving readability and navigation

## Requirements Validated

None.

## New Requirements Surfaced

None.

## Requirements Invalidated or Re-scoped

None.

## Deviations

Docker service name is chrysopedia-web not chrysopedia-web-8096 as plan stated (compose service vs container name). Had to run npm install on ub01 before type checking. TechniquePage.tsx was 505 lines not ~310 as estimated — component is larger than plan assumed.

## Known Limitations

None.

## Follow-ups

S03 (Key Moment Card Redesign) depends on this slice — the sidebar column constrains card width to 22rem which may affect card layout decisions.

## Files Created/Modified

- `frontend/src/App.css` — Widened .technique-page max-width from 48rem to 64rem. Added .technique-columns CSS grid (1fr 22rem), .technique-columns__main, .technique-columns__sidebar with sticky positioning, and @media 768px breakpoint for single-column collapse.
- `frontend/src/pages/TechniquePage.tsx` — Wrapped content sections in .technique-columns grid. Summary + body sections in __main div. Key moments + signal chains + plugins + related techniques in __sidebar div.
