style: fix footer version link color to match muted gray footer text

Author: Vit129

GLOSSARY.md

@@ -0,0 +1,12 @@
+# Glossary
+
+## Cloud Progress Sync
+
+Opt-in feature (not yet built) letting a learner's lesson progress (currently `localStorage`-only, per-browser) follow them across devices by saving to a cloud storage provider they sign into voluntarily.
+
+- **Provider phasing:** Google Drive first (feasible from a static GitHub Pages site — client-side OAuth via Google Identity Services + Drive API `appDataFolder`, no backend needed, free). iCloud deferred — requires a paid Apple Developer Program membership ($99/yr) plus a CloudKit JS container verified against the `vit129.github.io` domain; not started until that cost is accepted.
+- **Mechanism:** extends the existing "Export progress" flow (today: downloads a JSON file the learner manually re-imports on another device). Adds a "Save to Google Drive" / "Load from Google Drive" action using the same progress JSON shape already produced by the local export and consumed by `applyProgressData()`.
+- **Relationship to existing no-account design:** `PRODUCT.md`'s Out of Scope line ("Backend/accounts/cross-device progress sync") stays true for the *default* experience — no sign-in required, `localStorage` remains the source of truth. Cloud sync is an additive, opt-in layer: signing into Google is only needed if the learner wants cross-device sync. No custom backend is introduced — Drive API is called directly from the browser.
+- **Hard external blocker:** a Google Cloud Console project + OAuth 2.0 Client ID (configured with the `vit129.github.io` origin) must exist before any Drive-sync code can authenticate. This requires the repo owner's own Google account — Claude cannot create it. This is the actual next step before `dev-architect` can design the integration in detail.
+
+**Status:** scoped via `/interview`, 2026-07-29. Not yet designed or implemented.

index.html

@@ -419,6 +419,16 @@
       margin-top: 24px;
     }
 
+    footer #footer-version a {
+      color: inherit;
+      text-decoration: none;
+    }
+
+    footer #footer-version a:hover {
+      color: #9ca3af;
+      text-decoration: underline;
+    }
+
     @media (max-width: 1000px) {
       .courses-grid {
         grid-template-columns: 1fr 1fr;