fix(domino-maker): cuttable grid, printable divider, A4 print, hub dark sync

[devin-ai-integration]

Summary

Polishes the Domino Card Maker tool from #51 to address three asks: make it fit the KlassKit aesthetic (incl. hub dark-mode sync), lay tiles out as a gapless cuttable grid that still reads as a domino, and fix printing (divider line, A4 default, no extra blank pages). All edits are in apps/tools/domino-maker/index.html.

1. Hub dark-mode sync. The hub stores theme via Storage.set → localStorage[theme_hub] = JSON.stringify('dark'), i.e. the quoted string "dark". The tool compared the raw value === 'dark', which never matched. Fixed with a defensive parse:

function readStoredTheme(key) {
  const raw = localStorage.getItem(key);
  if (raw == null) return null;
  try { return JSON.parse(raw); } catch (e) { return raw; }
}

The tool's own theme_domino-maker choice still takes precedence over the hub (unchanged precedence). Also forced tile text color to #1e293b so words stay readable on the always-white tiles in dark mode (previously inherited the light body text and became near-invisible).

2. Cuttable domino grid. .page grid gap: 9mm 5mm → 0 and .domino-tile border-radius: 9px → 0, so tiles sit edge-to-edge and their borders form one continuous grid you can cut in straight lines. Each tile is still a domino: two .domino-halfs split by a centre divider. Shared tile borders (between dominoes) read as 2px+2px cut lines while the single 2px centre divider reads as the domino hinge.

3. Print fixes.

• Divider was background-color inside overflow:hidden → didn't print without Chrome's "Background graphics". Changed to border-left: 2px solid #1e293b (borders always print) + print-color-adjust: exact.
• @page { size: A4; margin: 0 } enforces A4 by default (verified 2 pages under both "Default" and "None" margins).
• Extra blank page per sheet was a sub-pixel overflow from height: 297mm on a 297mm box; print .page height set to 296mm, and on-screen container/gaps zeroed in print so nothing pushes content onto an extra sheet.

Verified in-browser: gapless grid, hub→tool dark sync, readable tiles in dark mode, and print preview showing exactly 2 A4 pages with visible dividers.

Link to Devin session: https://app.devin.ai/sessions/6a816cc7fd9a480a975d22ffdde85c3a
Requested by: @pod-III

[devin-ai-integration]

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Project	Deployment	Actions	Updated (UTC)
klasskit	Ready	Preview, Comment	Jun 18, 2026 6:03am