/* U-008: minimal shell styling, nothing to design-review yet -- real look
   and feel is PH3, starting from docs/wireframes/*.html. */
body { font-family: system-ui, sans-serif; margin: 0; }
#nav { display: flex; gap: 1rem; padding: 1rem; border-bottom: 1px solid #ddd; }
#nav a { text-decoration: none; color: #333; }
#nav a.active { font-weight: bold; }
#app { padding: 1rem; }