diff --git a/IPython/frontend/html/notebook/static/base/js/page.js b/IPython/frontend/html/notebook/static/base/js/page.js
index 7f1824d..76f0e18 100644
--- a/IPython/frontend/html/notebook/static/base/js/page.js
+++ b/IPython/frontend/html/notebook/static/base/js/page.js
@@ -18,7 +18,6 @@ var IPython = (function (IPython) {
 
     Page.prototype.style = function () {
         $('div#header').addClass('border-box-sizing').
-            addClass('ui-widget-content').
             css('border-top-style','none').
             css('border-left-style','none').
             css('border-right-style','none');
diff --git a/IPython/frontend/html/notebook/static/notebook/css/override.css b/IPython/frontend/html/notebook/static/notebook/css/override.css
index 631930a..6c0fb75 100644
--- a/IPython/frontend/html/notebook/static/notebook/css/override.css
+++ b/IPython/frontend/html/notebook/static/notebook/css/override.css
@@ -3,7 +3,6 @@ This is only required when different pages style the same element differently. T
 a hack to deal with our current css styles and no new styling should be added in this file.*/
 
 #ipython-main-app {
-    width: 100%;
     position: relative;
     font-size: 110%;
 }
\ No newline at end of file
diff --git a/IPython/frontend/html/notebook/static/tree/css/override.css b/IPython/frontend/html/notebook/static/tree/css/override.css
index 8ad84b2..8f607ea 100644
--- a/IPython/frontend/html/notebook/static/tree/css/override.css
+++ b/IPython/frontend/html/notebook/static/tree/css/override.css
@@ -3,6 +3,5 @@ This is only required when different pages style the same element differently. T
 a hack to deal with our current css styles and no new styling should be added in this file.*/
 
 #ipython-main-app {
-    width: 920px;
     margin: 30px auto 0px auto;
 }
diff --git a/IPython/frontend/html/notebook/templates/login.html b/IPython/frontend/html/notebook/templates/login.html
index 1eb3ce4..b44003d 100644
--- a/IPython/frontend/html/notebook/templates/login.html
+++ b/IPython/frontend/html/notebook/templates/login.html
@@ -11,7 +11,7 @@
 
 {% block site %}
 
-<div id="ipython-main-app">
+<div id="ipython-main-app" class="container">
 
     {% if login_available %}
     <div class="navbar">
diff --git a/IPython/frontend/html/notebook/templates/logout.html b/IPython/frontend/html/notebook/templates/logout.html
index 4289c4b..2d5eae9 100644
--- a/IPython/frontend/html/notebook/templates/logout.html
+++ b/IPython/frontend/html/notebook/templates/logout.html
@@ -10,7 +10,7 @@
 
 {% block site %}
 
-<div id="ipython-main-app">
+<div id="ipython-main-app" class="container">
 
     {% if message %}
       {% for key in message %}
diff --git a/IPython/frontend/html/notebook/templates/tree.html b/IPython/frontend/html/notebook/templates/tree.html
index e0f3e47..b7b0726 100644
--- a/IPython/frontend/html/notebook/templates/tree.html
+++ b/IPython/frontend/html/notebook/templates/tree.html
@@ -20,7 +20,7 @@ data-read-only={{read_only}}
 
 {% block site %}
 
-<div id="ipython-main-app">
+<div id="ipython-main-app" class="container">
 
 <div id="tabs" class="tabbable">
     <ul class="nav nav-tabs" id="tabs">