Nav: dark contrast bar instead of barely-visible cream tint

- bg #1a1410 (warm black) on light theme, cream on dark
- white-ish links/logo, red CTA stays
- drop bottom border, add soft shadow

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

index.html

@@ -150,22 +150,35 @@ section.section,
   nav { max-width: 1280px; }
 }
 
-/* Sticky nav поверх слайдов — компактный, с лёгким тинтом */
+/* Sticky nav поверх слайдов — компактный, контрастный */
 nav {
   position: sticky !important;
   top: 0 !important;
   z-index: 100;
   scroll-snap-align: none;
   height: 48px !important;
-  background: rgba(236, 228, 210, 0.92) !important;
+  background: #1a1410 !important;       /* тёмная плашка под кремовым фоном */
+  color: #f5efe1;
   backdrop-filter: blur(8px);
   -webkit-backdrop-filter: blur(8px);
-  box-shadow: 0 1px 0 var(--border);
-  border-bottom: 1px solid var(--border-strong) !important;
+  border: none !important;
+  box-shadow: 0 2px 12px rgba(0,0,0,0.08);
 }
 [data-theme="dark"] nav {
-  background: rgba(34, 29, 24, 0.92) !important;
+  background: #f5efe1 !important;
+  color: #1a1410;
 }
+nav .nav-link, nav .logo-text { color: rgba(245,239,225,0.85) !important; }
+nav .nav-link:hover { color: #fff !important; background: rgba(255,255,255,0.08) !important; }
+[data-theme="dark"] nav .nav-link, [data-theme="dark"] nav .logo-text { color: rgba(26,20,16,0.85) !important; }
+[data-theme="dark"] nav .nav-link:hover { color: #000 !important; background: rgba(0,0,0,0.08) !important; }
+nav .theme-toggle { color: rgba(245,239,225,0.7) !important; border-color: rgba(245,239,225,0.2) !important; }
+nav .theme-toggle:hover { color: #fff !important; background: rgba(255,255,255,0.08) !important; }
+nav .nav-cta {
+  background: var(--blue) !important;
+  color: #fff !important;
+}
+nav .nav-cta:hover { background: #c0322a !important; }
 nav .nav-inner { padding: 0 24px; }
 .logo-text { font-size: 1rem !important; }
 .logo-mark { font-size: 0.7rem !important; padding: 2px 6px !important; }