diff --git a/ft-app/app/routers/contracts.py b/ft-app/app/routers/contracts.py
index e927ac0..ccd5b63 100644
--- a/ft-app/app/routers/contracts.py
+++ b/ft-app/app/routers/contracts.py
@@ -164,6 +164,13 @@ def contract_detail(
                 "change": r.change,
             })
 
+        pos_totals = {
+            "long": sum(r.change for r in rankings if r.data_type == "long"),
+            "short": sum(r.change for r in rankings if r.data_type == "short"),
+        }
+    else:
+        pos_totals = {"long": 0, "short": 0}
+
     # Predict next trading day amplitude: mean of latest 5 diffs
     # Compute next trading date
     next_date = latest.date + timedelta(days=1) if latest else None
@@ -186,6 +193,7 @@ def contract_detail(
             pos_dates=pos_dates,
             selected_pos_date=selected_date,
             pos_data=pos_data,
+            pos_totals=pos_totals,
             next_amp=next_amp,
             next_date=next_date.strftime("%Y/%-m/%-d") if next_date else None,
             next_weekday=WEEKDAY_ZH.get(next_date.weekday(), "") if next_date else "",
diff --git a/ft-app/app/templates/contract.html b/ft-app/app/templates/contract.html
index 48224ad..f6ed68e 100644
--- a/ft-app/app/templates/contract.html
+++ b/ft-app/app/templates/contract.html
@@ -92,6 +92,15 @@
       </td>
     </tr>
     {% endfor %}
+    {% if dtype != 'volume' %}
+    <tr style="background:var(--th-bg);font-weight:600;">
+      <td></td><td style="text-align:right;">增减合计</td>
+      <td></td>
+      <td style="color:{% if pos_totals[dtype] > 0 %}var(--danger-fg){% elif pos_totals[dtype] < 0 %}var(--success-fg){% else %}var(--sub){% endif %};">
+        {% if pos_totals[dtype] > 0 %}+{% endif %}{{ pos_totals[dtype] }}
+      </td>
+    </tr>
+    {% endif %}
   </table>
   </div>
   {% endfor %}