diff --git a/unity-client/Assets/UI/MainMenu.uss b/unity-client/Assets/UI/MainMenu.uss
new file mode 100644
index 0000000..b02d4e9
--- /dev/null
+++ b/unity-client/Assets/UI/MainMenu.uss
@@ -0,0 +1,192 @@
+/* ============================================================
+   MainMenu.uss - Main Menu / Navigation Hub Styles
+   Commander AI Lab - Unity UI Toolkit
+   ============================================================ */
+
+/* ---------- Header Bar ---------- */
+.header-bar {
+  flex-direction: row;
+  justify-content: space-between;
+  align-items: center;
+  padding: 16px 24px;
+  background-color: rgba(15, 5, 25, 0.95);
+  border-bottom-width: 2px;
+  border-bottom-color: #6b21a8;
+}
+
+.app-title {
+  font-size: 28px;
+  color: #e9d5ff;
+  -unity-font-style: bold;
+  letter-spacing: 1px;
+}
+
+.version-label {
+  font-size: 12px;
+  color: #9ca3af;
+  padding: 4px 10px;
+  background-color: rgba(107, 33, 168, 0.3);
+  border-radius: 8px;
+}
+
+/* ---------- Server Config Panel ---------- */
+.server-config-panel {
+  margin: 16px 24px;
+  padding: 16px;
+  background-color: rgba(30, 15, 50, 0.8);
+  border-radius: 10px;
+  border-width: 1px;
+  border-color: #374151;
+}
+
+.server-row {
+  flex-direction: row;
+  align-items: center;
+  margin-top: 10px;
+}
+
+.server-url-input {
+  flex-grow: 1;
+  margin-right: 10px;
+}
+
+.server-url-input > .unity-text-field__input {
+  background-color: #1f1135;
+  border-color: #4b5563;
+  border-radius: 6px;
+  color: #e5e7eb;
+  padding: 8px 12px;
+  font-size: 14px;
+}
+
+.server-url-input > .unity-text-field__input:focus {
+  border-color: #a855f7;
+}
+
+.status-row {
+  flex-direction: row;
+  align-items: center;
+  margin-top: 10px;
+}
+
+.status-dot {
+  width: 12px;
+  height: 12px;
+  border-radius: 6px;
+  margin-right: 8px;
+}
+
+.status-connected {
+  background-color: #22c55e;
+}
+
+.status-disconnected {
+  background-color: #ef4444;
+}
+
+.status-connecting {
+  background-color: #eab308;
+}
+
+.status-text {
+  font-size: 13px;
+  color: #9ca3af;
+}
+
+/* ---------- Navigation Grid ---------- */
+.nav-grid {
+  flex-grow: 1;
+  padding: 8px 24px 16px 24px;
+}
+
+.nav-cards-row {
+  flex-direction: row;
+  justify-content: flex-start;
+  margin-bottom: 12px;
+}
+
+.nav-cards-row-single {
+  justify-content: flex-start;
+}
+
+/* ---------- Navigation Card ---------- */
+.nav-card {
+  width: 30%;
+  min-width: 220px;
+  margin-right: 12px;
+  padding: 20px;
+  background-color: rgba(30, 15, 50, 0.85);
+  border-radius: 12px;
+  border-width: 1px;
+  border-color: #374151;
+  transition-property: border-color, background-color;
+  transition-duration: 0.2s;
+}
+
+.nav-card:hover {
+  border-color: #a855f7;
+  background-color: rgba(45, 20, 75, 0.9);
+}
+
+.nav-card-icon {
+  width: 48px;
+  height: 48px;
+  margin-bottom: 12px;
+  border-radius: 10px;
+}
+
+/* Icon colour placeholders (swap for real textures later) */
+.collection-icon  { background-color: #3b82f6; }
+.deckbuilder-icon { background-color: #8b5cf6; }
+.deckgen-icon     { background-color: #10b981; }
+.simulator-icon   { background-color: #f59e0b; }
+.coach-icon       { background-color: #ec4899; }
+.training-icon    { background-color: #06b6d4; }
+.scanner-icon     { background-color: #6366f1; }
+
+.nav-card-title {
+  font-size: 18px;
+  color: #e9d5ff;
+  -unity-font-style: bold;
+  margin-bottom: 6px;
+}
+
+.nav-card-desc {
+  font-size: 12px;
+  color: #9ca3af;
+  margin-bottom: 14px;
+  white-space: normal;
+}
+
+/* ---------- Error Panel ---------- */
+.error-panel {
+  flex-direction: row;
+  align-items: center;
+  justify-content: space-between;
+  margin: 0 24px 12px 24px;
+  padding: 12px 16px;
+  background-color: rgba(127, 29, 29, 0.6);
+  border-radius: 8px;
+  border-width: 1px;
+  border-color: #dc2626;
+}
+
+.error-text {
+  font-size: 13px;
+  color: #fca5a5;
+  flex-grow: 1;
+  margin-right: 12px;
+}
+
+/* ---------- Footer ---------- */
+.footer {
+  padding: 12px 24px;
+  border-top-width: 1px;
+  border-top-color: #1f2937;
+  align-items: center;
+}
+
+.footer-text {
+  font-size: 11px;
+  color: #6b7280;
+}