feat(theme): add Archipelago deck brand palette

Pine + amber on a deep near-black ground, self-contained dark deck
canvas (.deck-root), display font. shadcn tokens left intact.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/style.css

@@ -73,6 +73,33 @@
   --radius-sm: calc(var(--radius) - 4px);
 }
 
+/* ─────────────────────────────────────────────────────────────
+   ARCHIPELAGO pitch-deck brand palette  (PLACEHOLDER — swap when real
+   brand assets land). Regenerative-tech: pine green + warm amber
+   on a deep near-black ground. Used by the self-contained dark
+   deck; the shadcn tokens above are left intact for other pages.
+   ───────────────────────────────────────────────────────────── */
+@theme {
+  --color-ink: hsl(160 28% 6%); /* deck ground */
+  --color-ink-2: hsl(160 24% 9%); /* raised panels */
+  --color-ink-3: hsl(158 20% 13%); /* cards / borders */
+
+  --color-pine-300: hsl(158 42% 62%);
+  --color-pine-400: hsl(159 45% 50%);
+  --color-pine-500: hsl(160 60% 40%);
+  --color-pine-600: hsl(162 66% 30%);
+
+  --color-amber-300: hsl(38 96% 70%);
+  --color-amber-400: hsl(36 95% 60%);
+  --color-amber-500: hsl(32 92% 52%);
+
+  --color-clay-400: hsl(14 72% 62%); /* farm / warmth accent */
+  --color-sand: hsl(44 30% 90%); /* primary deck text */
+  --color-sand-dim: hsl(150 8% 62%); /* muted deck text */
+
+  --font-display: 'Georgia', 'Times New Roman', serif;
+}
+
 @layer base {
   * {
     @apply border-border;
@@ -80,4 +107,13 @@
   body {
     @apply bg-background text-foreground;
   }
+
+  /* Deck root: self-contained dark canvas independent of shadcn tokens */
+  .deck-root {
+    background:
+      radial-gradient(120% 80% at 80% -10%, hsl(162 60% 14% / 0.55), transparent 60%),
+      radial-gradient(90% 70% at -10% 110%, hsl(32 80% 18% / 0.35), transparent 55%),
+      var(--color-ink);
+    color: var(--color-sand);
+  }
 }