diff --git a/packages/core/src/editor/text.ts b/packages/core/src/editor/text.ts
index bf22605e9..59fc55c3e 100644
--- a/packages/core/src/editor/text.ts
+++ b/packages/core/src/editor/text.ts
@@ -1,7 +1,9 @@
+import type { SceneNode } from '../scene-graph'
 import type { EditorContext } from './types'
 
 export function createTextActions(ctx: EditorContext) {
   let textBeforeEdit: string | null = null
+  let styleRunsBeforeEdit: SceneNode['styleRuns'] | null = null
 
   function startTextEditing(nodeId: string) {
     const te = ctx.getTextEditor()
@@ -9,6 +11,7 @@ export function createTextActions(ctx: EditorContext) {
     const node = ctx.graph.getNode(nodeId)
     if (!node) return
     textBeforeEdit = node.text
+    styleRunsBeforeEdit = structuredClone(node.styleRuns)
     ctx.state.editingTextId = nodeId
     if (te) {
       te.setRenderer(ctx.getRenderer())
@@ -22,28 +25,37 @@ export function createTextActions(ctx: EditorContext) {
     if (!te?.isActive) {
       ctx.state.editingTextId = null
       textBeforeEdit = null
+      styleRunsBeforeEdit = null
       return
     }
     const result = te.stop()
     if (!result) {
       ctx.state.editingTextId = null
       textBeforeEdit = null
+      styleRunsBeforeEdit = null
       ctx.requestRender()
       return
     }
     const prevText = textBeforeEdit ?? ''
+    const prevRuns = styleRunsBeforeEdit ?? []
     const newText = result.text
-    ctx.graph.updateNode(result.nodeId, { text: newText })
+    const node = ctx.graph.getNode(result.nodeId)
+    const newRuns = node ? structuredClone(node.styleRuns) : []
+    ctx.graph.updateNode(result.nodeId, { text: newText, styleRuns: newRuns })
     ctx.state.editingTextId = null
     textBeforeEdit = null
-    if (prevText !== newText) {
+    styleRunsBeforeEdit = null
+
+    const textChanged = prevText !== newText
+    const runsChanged = JSON.stringify(prevRuns) !== JSON.stringify(newRuns)
+    if (textChanged || runsChanged) {
       ctx.undo.push({
         label: 'Edit text',
         forward: () => {
-          ctx.graph.updateNode(result.nodeId, { text: newText })
+          ctx.graph.updateNode(result.nodeId, { text: newText, styleRuns: newRuns })
         },
         inverse: () => {
-          ctx.graph.updateNode(result.nodeId, { text: prevText })
+          ctx.graph.updateNode(result.nodeId, { text: prevText, styleRuns: prevRuns })
         }
       })
     }
diff --git a/tests/engine/text-edit-undo.test.ts b/tests/engine/text-edit-undo.test.ts
index 4d19e8652..784f75ee4 100644
--- a/tests/engine/text-edit-undo.test.ts
+++ b/tests/engine/text-edit-undo.test.ts
@@ -3,6 +3,7 @@ import { describe, test, expect } from 'bun:test'
 import { SceneGraph, TextEditor, UndoManager } from '@open-pencil/core'
 import { createTextActions } from '@open-pencil/core/editor'
 
+import type { StyleRun } from '@open-pencil/core'
 import type { EditorContext, EditorState } from '@open-pencil/core/editor'
 
 function setup() {
@@ -117,4 +118,58 @@ describe('text edit undo', () => {
     undo.undo()
     expect(graph.getNode(textNode.id)!.text).toBe('Hello')
   })
+
+  test('undo restores styleRuns when they changed during editing', () => {
+    const { graph, undo, textEditor, textNode, actions } = setup()
+
+    const boldRun: StyleRun = { start: 0, length: 5, style: { fontWeight: 700 } }
+    graph.updateNode(textNode.id, { styleRuns: [boldRun] })
+
+    actions.startTextEditing(textNode.id)
+
+    textEditor.insert(' World', textNode)
+    const newRuns: StyleRun[] = [
+      { start: 0, length: 5, style: { fontWeight: 700 } },
+      { start: 5, length: 6, style: { fontWeight: 400 } },
+    ]
+    graph.updateNode(textNode.id, { text: textEditor.state!.text, styleRuns: newRuns })
+
+    actions.commitTextEdit()
+
+    expect(graph.getNode(textNode.id)!.styleRuns).toEqual(newRuns)
+    expect(undo.canUndo).toBe(true)
+
+    undo.undo()
+    expect(graph.getNode(textNode.id)!.text).toBe('Hello')
+    expect(graph.getNode(textNode.id)!.styleRuns).toEqual([boldRun])
+
+    undo.redo()
+    expect(graph.getNode(textNode.id)!.text).toBe('Hello World')
+    expect(graph.getNode(textNode.id)!.styleRuns).toEqual(newRuns)
+  })
+
+  test('undo entry is pushed when only styleRuns changed', () => {
+    const { graph, undo, textNode, actions } = setup()
+
+    actions.startTextEditing(textNode.id)
+
+    const newRuns: StyleRun[] = [{ start: 0, length: 5, style: { fontWeight: 700 } }]
+    graph.updateNode(textNode.id, { styleRuns: newRuns })
+
+    actions.commitTextEdit()
+
+    expect(undo.canUndo).toBe(true)
+
+    undo.undo()
+    expect(graph.getNode(textNode.id)!.styleRuns).toEqual([])
+  })
+
+  test('no undo entry when neither text nor styleRuns changed', () => {
+    const { undo, actions, textNode } = setup()
+
+    actions.startTextEditing(textNode.id)
+    actions.commitTextEdit()
+
+    expect(undo.canUndo).toBe(false)
+  })
 })