Add nav styling — bold Probe Results, separator before Glossary

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

Author: MDA2AV

docs/assets/css/custom.css

@@ -0,0 +1,11 @@
+/* Probe Results — primary nav item */
+nav.hextra-max-navbar-width a[href*="/probe-results/"] {
+  font-weight: 700;
+}
+
+/* Separator before Glossary */
+nav.hextra-max-navbar-width a[href*="/glossary/"] {
+  margin-left: 12px;
+  padding-left: 14px;
+  border-left: 1px solid rgba(128, 128, 128, 0.3);
+}