diff --git a/apps/web/src/shared/gov/flow/flow-layout.ts b/apps/web/src/shared/gov/flow/flow-layout.ts
index f37aa47..9dda365 100644
--- a/apps/web/src/shared/gov/flow/flow-layout.ts
+++ b/apps/web/src/shared/gov/flow/flow-layout.ts
@@ -428,11 +428,33 @@ function layoutManualFlow(graph: FlowGraph): FlowLayoutResult {
     maxY = Math.max(maxY, caption.y + 4);
   }
 
+  /*
+   * 水平居中:画幅有 1000 的下限,内容却总从左缘 PAD 起 —— 画得比 1000 窄时
+   * 余白全堆在右边,图看着左贴(保存后经归一化尤其明显)。
+   * 定完画幅宽度后把内容平移到正中,两侧余白对称;纵向保持收顶,不居中。
+   */
+  let cMinX = Infinity;
+  for (const shape of shapes) cMinX = Math.min(cMinX, shape.x);
+  for (const connection of connections) for (const p of connection.waypoints) cMinX = Math.min(cMinX, p.x);
+  for (const caption of captions) cMinX = Math.min(cMinX, caption.x - estTextWidth(caption.text, 10) / 2);
+  if (!Number.isFinite(cMinX)) cMinX = 0;
+  const contentW = maxX - cMinX;
+  const width = Math.max(1000, contentW + 40);
+  const dxCenter = (width - contentW) / 2 - cMinX;
+  if (dxCenter !== 0) {
+    for (const shape of shapes) shape.x += dxCenter;
+    for (const caption of captions) caption.x += dxCenter;
+    for (const connection of connections) {
+      connection.waypoints = connection.waypoints.map((p) => ({ x: p.x + dxCenter, y: p.y }));
+      if (connection.label) connection.label = { ...connection.label, x: connection.label.x + dxCenter };
+    }
+  }
+
   return {
     shapes,
     captions,
     connections,
-    width: Math.max(1000, maxX + 40),
+    width,
     height: maxY + 44,
     ghost: false,
   };