style: enlarge announcement bar text and padding

Bump announcement font-size to 1.05rem (~1.5x) and vertical padding to
0.75rem for better readability.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Author: DavertMik

src/components/Announcement.astro

@@ -32,7 +32,7 @@ import { announcement } from '../config/announcement';
         border-radius: 5px;
         border: 2px dashed color-mix(in srgb, var(--cc-announce) 34%, transparent);
         background: color-mix(in srgb, var(--cc-announce) 3%, transparent);
-        font-size: 0.7rem;
+        font-size: 1.05rem;
         font-weight: bold;
         line-height: 1.3;
         color: var(--cc-announce);