diff --git a/cookbook/pageindex_RAG_simple.ipynb b/cookbook/pageindex_RAG_simple.ipynb
index 4cf9c92..2d53c3b 100644
--- a/cookbook/pageindex_RAG_simple.ipynb
+++ b/cookbook/pageindex_RAG_simple.ipynb
@@ -85,7 +85,7 @@
         "id": "edTfrizMFK4c"
       },
       "source": [
-        "### Install dependencies"
+        "#### Install dependencies"
       ]
     },
     {
@@ -106,7 +106,7 @@
         "id": "WVEWzPKGcG1M"
       },
       "source": [
-        "### Setup environment"
+        "#### Setup environment"
       ]
     },
     {
@@ -134,7 +134,7 @@
         "id": "AR7PLeVbcG1N"
       },
       "source": [
-        "### Define utility functions"
+        "#### Define utility functions"
       ]
     },
     {
@@ -198,7 +198,7 @@
         "id": "Mzd1VWjwMUJL"
       },
       "source": [
-        "### Submit a document for PageIndex tree generation"
+        "#### Submit a document for PageIndex tree generation"
       ]
     },
     {
@@ -244,7 +244,7 @@
         "id": "4-Hrh0azcG1N"
       },
       "source": [
-        "### Get the generated PageIndex tree structure"
+        "#### Get the generated PageIndex tree structure"
       ]
     },
     {
@@ -356,7 +356,7 @@
       "cell_type": "markdown",
       "metadata": {},
       "source": [
-        "### Use LLM for tree search and identify nodes that might contain relevant context"
+        "#### Use LLM for tree search and identify nodes that might contain relevant context"
       ]
     },
     {
@@ -396,7 +396,7 @@
       "cell_type": "markdown",
       "metadata": {},
       "source": [
-        "### Print retrieved nodes and reasoning process"
+        "#### Print retrieved nodes and reasoning process"
       ]
     },
     {
@@ -455,7 +455,7 @@
       "cell_type": "markdown",
       "metadata": {},
       "source": [
-        "### Extract relevant context from retrieved nodes"
+        "#### Extract relevant context from retrieved nodes"
       ]
     },
     {
@@ -507,7 +507,7 @@
       "cell_type": "markdown",
       "metadata": {},
       "source": [
-        "### Generate answer based on retrieved context"
+        "#### Generate answer based on retrieved context"
       ]
     },
     {