feat(appearance): token-driven theme engine with schemes and FOUC-safe boot

applyAppearance is the single writer of styling to the DOM (the .dark class plus data-scheme/-no-transparency/-density/-reduce-motion and the custom-accent/type-scale CSS vars). An external pre-paint /theme-boot.js replays a cached snapshot before first paint and complies with the production CSP (script-src 'self'), fixing the long-standing theme FOUC. Adds seven color schemes (incl. a true high-contrast that raises neutral contrast), a custom accent with auto-derived legible text, an extended token layer (accent variants, status/shadow/overlay/inverse), a scheme-gated legacy accent bridge, and a transparency-off layer. The default scheme sets no attributes, so existing users are unaffected.
2026-06-30 18:46:00 +00:00 · 2026-06-29 10:59:39 +02:00
parent 22aa28ee46
commit ad0da3d6c8
9 changed files with 568 additions and 20 deletions
@@ -0,0 +1,59 @@
+/*
+ * Pre-paint appearance boot — kills the flash of default/wrong theme (FOUC).
+ *
+ * Loaded as an external, render-blocking CLASSIC script in <head> (NOT a module)
+ * so it runs before first paint AND complies with the production CSP
+ * (script-src 'self'; inline scripts are blocked). It reads the compact snapshot
+ * written by client/src/theme/applyAppearance.ts and applies it verbatim. Keep
+ * this in sync with that module's snapshot shape + apply logic.
+ *
+ * It must never throw — any failure silently falls back to the default look.
+ */
+(function () {
+  try {
+    var raw = localStorage.getItem('trek_appearance');
+    if (!raw) return;
+    var s = JSON.parse(raw);
+    if (!s || s.v !== 1) return;
+
+    var root = document.documentElement;
+    var path = location.pathname;
+    var isShared = path.indexOf('/shared/') === 0 || path.indexOf('/public/') === 0;
+
+    var dark;
+    if (isShared) dark = false;
+    else if (s.darkMode === 'auto') dark = window.matchMedia('(prefers-color-scheme: dark)').matches;
+    else dark = s.darkMode === true || s.darkMode === 'dark';
+    root.classList.toggle('dark', dark);
+
+    var scheme = isShared ? 'default' : s.scheme;
+    if (scheme && scheme !== 'default') root.setAttribute('data-scheme', scheme);
+    if (!isShared && s.noTransparency) root.setAttribute('data-no-transparency', '');
+    if (s.density === 'compact') root.setAttribute('data-density', 'compact');
+    if (s.reduceMotion) root.setAttribute('data-reduce-motion', '');
+
+    if (!isShared && scheme === 'custom' && s.accent) {
+      root.style.setProperty('--accent-custom-light', s.accent.light);
+      root.style.setProperty('--accent-custom-dark', s.accent.dark);
+      if (s.accentText) {
+        root.style.setProperty('--accent-custom-text-light', s.accentText.light);
+        root.style.setProperty('--accent-custom-text-dark', s.accentText.dark);
+      }
+    }
+
+    var ts = s.typeScale || {};
+    setScale('--fs-scale-title', ts.title);
+    setScale('--fs-scale-subtitle', ts.subtitle);
+    setScale('--fs-scale-body', ts.body);
+    setScale('--fs-scale-caption', ts.caption);
+    if (typeof s.fontScale === 'number' && s.fontScale !== 1) {
+      root.style.fontSize = s.fontScale * 100 + '%';
+    }
+
+    function setScale(name, v) {
+      if (typeof v === 'number' && v !== 1) root.style.setProperty(name, String(v));
+    }
+  } catch (e) {
+    /* never block boot */
+  }
+})();