feat: primary node switching in topology graph

public/styles/main.css

@@ -68,6 +68,7 @@ button:disabled {
 /* === Icon-Only Button Style (Minimal) === */
 .btn-icon,
 .theme-toggle,
+.random-primary-toggle,
 .burger-btn,
 .primary-node-refresh,
 .filter-pill-remove,
@@ -96,6 +97,7 @@ button:disabled {
 
 .btn-icon:hover,
 .theme-toggle:hover,
+.random-primary-toggle:hover,
 .burger-btn:hover,
 .primary-node-refresh:hover,
 .filter-pill-remove:hover,
@@ -527,6 +529,44 @@ p {
     animation: spin 1s linear infinite;
 }
 
+.random-primary-toggle {
+    width: 32px;
+    height: 32px;
+    border-radius: 6px;
+}
+
+.random-primary-toggle svg {
+    width: 20px;
+    height: 20px;
+    transition: transform 0.3s ease;
+}
+
+.random-primary-toggle:hover {
+    background: rgba(255, 255, 255, 0.1);
+}
+
+.random-primary-toggle:hover svg {
+    transform: rotate(180deg);
+}
+
+.random-primary-toggle.spinning svg {
+    animation: spin 1s linear infinite;
+}
+
+.random-primary-toggle:disabled {
+    opacity: 0.5;
+    cursor: not-allowed;
+}
+
+/* Topology graph node interactions */
+#topology-graph-container .node {
+    cursor: pointer;
+}
+
+#topology-graph-container .node:hover circle:first-child {
+    filter: brightness(1.2);
+}
+
 @keyframes spin {
     from {
         transform: rotate(0deg);