docs: center doc-nav pills and fix include border color

Made-with: Cursor

Author: TMHSDigital

docs/_includes/page-nav.html

@@ -1,4 +1,4 @@
-<div class="doc-nav" style="margin-top:2.5rem; border-top:1px solid #21262d; padding-top:1.5rem;">
+<div class="doc-nav" style="margin-top:2.5rem; border-top:1px solid #d0d7de; padding-top:1.5rem;">
   <a href="{{ '/' | relative_url }}">Home</a>
   <a href="{{ '/ARCHITECTURE.html' | relative_url }}">Architecture</a>
   <a href="{{ '/DEVELOPER_GUIDE.html' | relative_url }}">Developer Guide</a>

docs/_layouts/default.html

@@ -224,6 +224,7 @@
       .doc-nav {
         display: flex;
         flex-wrap: wrap;
+        justify-content: center;
         gap: 8px;
         margin: 2rem 0 1rem;
       }