Polish

Polish

Screenshot-diff-iterate loop for UI refinement. Replaces the manual "fix CSS, check browser, repeat" cycle that burned 320-minute sessions.

This is internal tooling for GIGO's own product site and docs. Not a public plugin skill.

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Before Starting

1. Get the target. The operator provides a URL or file path to polish.
2. Get the spec. Either:
   • Operator provides a visual spec inline or points to a file
   • Read docs/gigo/ui-spec.md if it exists
   • If no spec exists, ask: "What should this look like? Give me layout rules, breakpoints, and copy requirements — or I'll screenshot first and we'll build the spec from what's there."
3. Branch. If available, use worktree isolation (isolation: "worktree") so failed iterations don't pollute main. If not, create a feature branch.

The Loop

For each iteration (max 5):

1. Screenshot

Use Playwright MCP to capture the page at three viewports:

• Mobile: 375px wide (portrait phone)
• Tablet: 768px wide (landscape tablet)
• Desktop: 1440px wide (standard desktop)

browser_navigate → target URL
browser_resize → width, height
browser_take_screenshot → save/analyze

If the page is local HTML, serve it first (python3 -m http.server) or use a file:// URL.

2. Analyze

Compare each screenshot against the visual spec criteria. Check:

• Layout: Container widths, grid behavior, flex wrapping, element ordering
• Spacing: Margins, padding, gaps between elements (consistent with spec)
• Responsiveness: No horizontal scroll, elements reflow correctly at each breakpoint
• Typography: Font sizes readable (min 14px body, min 12px labels), hierarchy clear
• Copy: Text matches spec requirements, no orphaned words in headings
• Interactive elements: Hover states, focus indicators, cursor changes
• Visual polish: Alignment, color consistency, border radius consistency

3. Fix

If issues found:

• Make targeted CSS/HTML fixes — change the minimum needed to resolve the issue
• Don't refactor unrelated code during a polish pass
• Prefer CSS fixes over HTML restructuring when possible

4. Re-screenshot

After fixes, re-screenshot the same three viewports. Compare against the spec again.

5. Report or Continue

• All criteria met: Exit the loop. Report changes made with before/after descriptions.
• Issues remain, iterations left: Continue to next iteration.
• 5 iterations reached, issues remain: Exit the loop. Report what was fixed, what remains, and why convergence failed.

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Convergence Criteria

The loop exits successfully when ALL of these pass at ALL three viewports:

• No horizontal scroll
• All layout rules from spec are satisfied
• Copy matches spec requirements
• No elements overlap or clip unexpectedly
• Text is readable at specified minimum sizes

When It's Not Converging

If the same issue persists across 2+ iterations, stop and diagnose:

• Is the spec contradictory? (e.g., fixed width + no scroll at narrow viewport)
• Is the fix being overridden by another CSS rule? (specificity problem)
• Is this a fundamental layout issue that needs a structural change, not a CSS tweak?

Surface the diagnosis to the operator rather than burning more iterations.

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Output

When the loop completes, report:

## Polish Report: [page name]

**Iterations:** N of 5
**Result:** Converged | Partial (issues remaining)

### Changes Made
1. [viewport] [what changed] — [why]
2. ...

### Remaining Issues (if any)
1. [issue] — [why it didn't converge]

### Recommendations
- [anything that needs a structural change, not polish]

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References

• references/visual-spec.md — how to write visual specs (format, breakpoints, criteria)
• references/screenshot-diff.md — Playwright MCP integration details, diff strategy