diff --git a/IPython/html/static/notebook/js/maintoolbar.js b/IPython/html/static/notebook/js/maintoolbar.js
index bed81dc..c054e06 100644
--- a/IPython/html/static/notebook/js/maintoolbar.js
+++ b/IPython/html/static/notebook/js/maintoolbar.js
@@ -35,7 +35,7 @@ define([
                 {
                     id : 'save_b',
                     label : 'Save and Checkpoint',
-                    icon : 'icon-save',
+                    icon : 'fa fa-save',
                     callback : function () {
                         that.notebook.save_checkpoint();
                         }
@@ -46,7 +46,7 @@ define([
                 {
                     id : 'insert_below_b',
                     label : 'Insert Cell Below',
-                    icon : 'icon-plus-sign',
+                    icon : 'fa fa-plus',
                     callback : function () {
                         that.notebook.insert_cell_below('code');
                         that.notebook.select_next();
@@ -59,7 +59,7 @@ define([
                 {
                     id : 'cut_b',
                     label : 'Cut Cell',
-                    icon : 'icon-cut',
+                    icon : 'fa fa-cut',
                     callback : function () {
                         that.notebook.cut_cell();
                         }
@@ -67,7 +67,7 @@ define([
                 {
                     id : 'copy_b',
                     label : 'Copy Cell',
-                    icon : 'icon-copy',
+                    icon : 'fa fa-copy',
                     callback : function () {
                         that.notebook.copy_cell();
                         }
@@ -75,7 +75,7 @@ define([
                 {
                     id : 'paste_b',
                     label : 'Paste Cell Below',
-                    icon : 'icon-paste',
+                    icon : 'fa fa-paste',
                     callback : function () {
                         that.notebook.paste_cell_below();
                         }
@@ -86,7 +86,7 @@ define([
                 {
                     id : 'move_up_b',
                     label : 'Move Cell Up',
-                    icon : 'icon-arrow-up',
+                    icon : 'fa fa-arrow-up',
                     callback : function () {
                         that.notebook.move_cell_up();
                         }
@@ -94,7 +94,7 @@ define([
                 {
                     id : 'move_down_b',
                     label : 'Move Cell Down',
-                    icon : 'icon-arrow-down',
+                    icon : 'fa fa-arrow-down',
                     callback : function () {
                         that.notebook.move_cell_down();
                         }
@@ -106,7 +106,7 @@ define([
                 {
                     id : 'run_b',
                     label : 'Run Cell',
-                    icon : 'icon-play',
+                    icon : 'fa fa-play',
                     callback : function () {
                         // emulate default shift-enter behavior
                         that.notebook.execute_cell_and_select_below();
@@ -115,7 +115,7 @@ define([
                 {
                     id : 'interrupt_b',
                     label : 'Interrupt',
-                    icon : 'icon-stop',
+                    icon : 'fa fa-stop',
                     callback : function () {
                         that.notebook.session.interrupt_kernel();
                         }
@@ -123,7 +123,7 @@ define([
                 {
                     id : 'repeat_b',
                     label : 'Restart Kernel',
-                    icon : 'icon-repeat',
+                    icon : 'fa fa-repeat',
                     callback : function () {
                         that.notebook.restart_kernel();
                         }
diff --git a/IPython/html/static/notebook/less/notificationarea.less b/IPython/html/static/notebook/less/notificationarea.less
index 5b3fd52..00073c0 100644
--- a/IPython/html/static/notebook/less/notificationarea.less
+++ b/IPython/html/static/notebook/less/notificationarea.less
@@ -28,19 +28,19 @@
 }
 
 .edit_mode_icon:before {
-     .icon(@pencil);
+     content: @fa-var-pencil;
 }
 
 .command_mode_icon:before {
-     .icon(' ');
+     content: ' ';
 }
 
 .kernel_idle_icon:before {
-     .icon(@circle-blank);
+     content: @fa-var-circle-o;
 }
 
 .kernel_busy_icon:before {
-     .icon(@circle);
+     content: @fa-var-circle;
 }
 
 
diff --git a/IPython/html/static/tree/less/tree.less b/IPython/html/static/tree/less/tree.less
index 1827f97..a480d67 100644
--- a/IPython/html/static/tree/less/tree.less
+++ b/IPython/html/static/tree/less/tree.less
@@ -141,9 +141,9 @@ input.engine_num_input {
 }
 
 .folder_icon:before {
-    .icon(@folder-close-alt)
+    content: @fa-var-folder-o
 }
 
 .notebook_icon:before {
-    .icon(@book)
+    content: @fa-var-book
 }