fix: restore white text in kdoc-hero on why-ours page

The redesign CSS was forcing .kdoc-hero__title to var(--dbn-blue) (#00205b)
— the same color as the hero background, making it invisible. The kicker
was also overridden to red, which clashed with the dark navy overlay.

Added more-specific .kdoc-hero .kdoc-hero__* overrides to restore white text.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

assets/css/dbn-tools-redesign.css

@@ -746,6 +746,9 @@ body[data-active-tool='citations'] .results {
 .kdoc-hero {
   border-bottom: 4px solid var(--dbn-gold);
 }
+.kdoc-hero .kdoc-hero__title { color: #fff; }
+.kdoc-hero .kdoc-hero__kicker { color: rgba(255,255,255,0.8) !important; }
+.kdoc-hero .kdoc-hero__sub { color: rgba(255,255,255,0.88); }
 
 @media (max-width: 1180px) {
   .workspace {