fix: Unser Versprechen heller als Footer (navy-light vs navy)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

vorschau/css/style.css

@@ -90,7 +90,7 @@ a { color:inherit; text-decoration:none; }
 .section { padding:88px 0; }
 .section-base { background:var(--base); }
 .section-alt { background:var(--alt-solid); }
-.section-dark { background:var(--navy); color:var(--white); }
+.section-dark { background:var(--navy-light); color:var(--white); }
 
 .section-title { font-size:2rem; font-weight:700; color:var(--navy); text-align:center; margin-bottom:16px; letter-spacing:-0.01em; }
 .section-dark .section-title { color:var(--white); }