diff --git a/IPython/html/static/notebook/less/textcell.less b/IPython/html/static/notebook/less/textcell.less
index 237c23d..b02c55f 100644
--- a/IPython/html/static/notebook/less/textcell.less
+++ b/IPython/html/static/notebook/less/textcell.less
@@ -49,5 +49,11 @@ div.cell.text_cell.rendered {
 .cm-s-heading-2 { font-size: 130%; }
 .cm-s-heading-3 { font-size: 120%; }
 .cm-s-heading-4 { font-size: 110%; }
-.cm-s-heading-5 { font-size: 100%; }
-.cm-s-heading-6 { font-size: 90%; }
+.cm-s-heading-5 {
+    font-size: 100%; 
+    font-style: italic;
+}
+.cm-s-heading-6 {
+    font-size: 90%; 
+    font-style: italic;
+}
diff --git a/IPython/html/static/style/ipython.min.css b/IPython/html/static/style/ipython.min.css
index ba7d1b6..9c5079b 100644
--- a/IPython/html/static/style/ipython.min.css
+++ b/IPython/html/static/style/ipython.min.css
@@ -1149,9 +1149,11 @@ div.cell.text_cell.rendered {
 }
 .cm-s-heading-5 {
   font-size: 100%;
+  font-style: italic;
 }
 .cm-s-heading-6 {
   font-size: 90%;
+  font-style: italic;
 }
 .widget-area {
   /*
diff --git a/IPython/html/static/style/style.min.css b/IPython/html/static/style/style.min.css
index c13aa2c..4a86410 100644
--- a/IPython/html/static/style/style.min.css
+++ b/IPython/html/static/style/style.min.css
@@ -8773,9 +8773,11 @@ div.cell.text_cell.rendered {
 }
 .cm-s-heading-5 {
   font-size: 100%;
+  font-style: italic;
 }
 .cm-s-heading-6 {
   font-size: 90%;
+  font-style: italic;
 }
 .widget-area {
   /*