diff --git a/src/modules/lesson-preparation/hooks/expanded-slice.ts b/src/modules/lesson-preparation/hooks/expanded-slice.ts
new file mode 100644
index 0000000..f4e7e25
--- /dev/null
+++ b/src/modules/lesson-preparation/hooks/expanded-slice.ts
@@ -0,0 +1,56 @@
+import type { StateCreator } from "zustand";
+import type { EditorState } from "./use-lesson-plan-editor";
+
+export interface ExpandedSlice {
+  /** 已展开到正文流的节点 ID */
+  expandedNodeIds: string[];
+  /** v3 迁移过来的失效锚点提示（按 planId 记录是否已 dismiss） */
+  legacyAnchorDismissed: Record<string, boolean>;
+  toggleExpand: (nodeId: string) => void;
+  setExpanded: (nodeIds: string[]) => void;
+  isExpanded: (nodeId: string) => boolean;
+  dismissLegacyAnchor: (planId: string) => void;
+  /** 同步 doc.expandedNodeIds（保存/加载时调用） */
+  syncFromDoc: (expandedNodeIds: string[]) => void;
+}
+
+export const createExpandedSlice: StateCreator<
+  EditorState,
+  [],
+  [],
+  ExpandedSlice
+> = (set, get) => ({
+  expandedNodeIds: [],
+  legacyAnchorDismissed: {},
+
+  toggleExpand: (nodeId) => {
+    get().pushHistory();
+    set((s) => {
+      const isExp = s.expandedNodeIds.includes(nodeId);
+      const next = isExp
+        ? s.expandedNodeIds.filter((id) => id !== nodeId)
+        : [...s.expandedNodeIds, nodeId];
+      // 同步到 doc
+      return {
+        expandedNodeIds: next,
+        doc: { ...s.doc, expandedNodeIds: next },
+        isDirty: true,
+      };
+    });
+  },
+
+  setExpanded: (nodeIds) =>
+    set((s) => ({
+      expandedNodeIds: nodeIds,
+      doc: { ...s.doc, expandedNodeIds: nodeIds },
+    })),
+
+  isExpanded: (nodeId) => get().expandedNodeIds.includes(nodeId),
+
+  dismissLegacyAnchor: (planId) =>
+    set((s) => ({
+      legacyAnchorDismissed: { ...s.legacyAnchorDismissed, [planId]: true },
+    })),
+
+  syncFromDoc: (expandedNodeIds) => set({ expandedNodeIds }),
+});