Repaint theme blue with larger typography

Swap the cherry-red primary for the logo's blue, bump body 13→15px
and h1 32→40px, and add semantic tokens (--bg-*, --accent-*, --text-*)
so future palette shifts are a single-file edit. Cherry-red survives
only for danger states and the brand cherry mark.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

src/routes/betas/+page.svelte

@@ -30,13 +30,14 @@
     h1 {
         color: var(--cream);
         font-family: var(--font-display);
-        font-size: 32px;
-        letter-spacing: 2px;
-        margin: 0 0 20px;
+        font-size: var(--text-3xl);
+        letter-spacing: var(--tracking-display);
+        line-height: var(--leading-tight);
+        margin: 0 0 28px;
     }
     .empty {
         color: var(--ink-500);
         font-family: var(--font-mono);
-        font-size: 13px;
+        font-size: var(--text-base);
     }
 </style>