feat(glossary): add step 21 smart navigation

src/styles/global.css

@@ -117,6 +117,24 @@ header{
     opacity 120ms var(--ease-out);
 }
 
+/* ===== SiteNav : lien actif ===== */
+/* ===== SiteNav : lien actif ===== */
+.site-nav a[aria-current="page"],
+.site-nav a.is-active,
+.site-nav a[data-active="true"]{
+  position: relative;
+  color: #00d9ff;
+  border-color: rgba(0,217,255,0.42);
+  background:
+    radial-gradient(circle at 50% 50%, rgba(0,217,255,0.16), transparent 68%),
+    rgba(0,217,255,0.075);
+  box-shadow:
+    0 0 0 1px rgba(0,217,255,0.12),
+    0 0 14px rgba(0,217,255,0.18),
+    inset 0 0 14px rgba(0,217,255,0.045);
+  opacity: 1;
+}
+
 .site-nav a:hover{
   transform: translateY(-1px);
   background: rgba(0,217,255,.08);