style: change header background from blue-gray to dark gray

- Update .cv-title-badges-header background color
- Change from #2c3e50 (dark blue-gray) to #303030 (dark gray)
- Provides a more neutral, professional appearance

static/css/main.css

@@ -246,7 +246,7 @@ a:hover {
 /* Professional Title Badges - Spans Both Columns */
 .cv-title-badges-header {
     grid-column: 1 / -1; /* Span all columns */
-    background: #2c3e50 !important; /* Elegant dark blue-gray */
+    background: #303030 !important; /* Elegant dark gray */
     padding: 0.75rem 2rem;
     display: flex;
     flex-wrap: wrap;