diff --git a/main.py b/main.py
index b6455fc..bf34d82 100644
--- a/main.py
+++ b/main.py
@@ -143,6 +143,15 @@ def index():
             background: rgba(255,255,255,0.2);
         }
 
+        /* Sub-sequence accent (teal) */
+        .body--dark .subsegment-card > .q-expansion-item__container > .q-item {
+            border-left: 6px solid #06B6D4;
+            padding-left: 10px;
+        }
+        .body--dark .subsegment-card .q-expansion-item__toggle-icon {
+            color: #06B6D4 !important;
+        }
+
         /* Secondary pane teal accent */
         .pane-secondary .q-field--outlined.q-field--focused .q-field__control:after {
             border-color: #06B6D4 !important;
diff --git a/tab_batch_ng.py b/tab_batch_ng.py
index 34845f6..da47601 100644
--- a/tab_batch_ng.py
+++ b/tab_batch_ng.py
@@ -317,7 +317,8 @@ def _render_sequence_card(i, seq, batch_list, data, file_path, state,
     else:
         label = f'Sequence #{seq_num}'
 
-    with ui.expansion(label, icon='movie').classes('w-full'):
+    exp_classes = 'w-full subsegment-card' if is_subsegment(seq_num) else 'w-full'
+    with ui.expansion(label, icon='movie').classes(exp_classes):
         # --- Action row ---
         with ui.row().classes('w-full q-gutter-sm action-row'):
             # Copy from source