diff --git a/IPython/frontend/html/notebook/static/ipython/base/less/base.less b/IPython/frontend/html/notebook/static/ipython/base/less/base.less
index e858f7a..d0f0249 100644
--- a/IPython/frontend/html/notebook/static/ipython/base/less/base.less
+++ b/IPython/frontend/html/notebook/static/ipython/base/less/base.less
@@ -1,4 +1,9 @@
+// Our base less styles. This should be @import'ed by the main .less
+// files of each page. This file should not itself be compiled to css.
+
 @import "../../../components/bootstrap/less/bootstrap.less";
 @import "variables.less";
+@import "mixins.less";
 @import "flexbox.less";
 @import "page.less";
+
diff --git a/IPython/frontend/html/notebook/static/ipython/base/less/mixins.less b/IPython/frontend/html/notebook/static/ipython/base/less/mixins.less
new file mode 100644
index 0000000..2032997
--- /dev/null
+++ b/IPython/frontend/html/notebook/static/ipython/base/less/mixins.less
@@ -0,0 +1,11 @@
+// Mixin CSS classes
+
+.border-box-sizing {
+    box-sizing: border-box;
+    -moz-box-sizing: border-box;
+    -webkit-box-sizing: border-box;
+}
+
+.corner-all {
+    border-radius: @corner_radius;
+}
\ No newline at end of file
diff --git a/IPython/frontend/html/notebook/static/ipython/base/less/variables.less b/IPython/frontend/html/notebook/static/ipython/base/less/variables.less
index fe3b15d..084d40f 100644
--- a/IPython/frontend/html/notebook/static/ipython/base/less/variables.less
+++ b/IPython/frontend/html/notebook/static/ipython/base/less/variables.less
@@ -1,5 +1,3 @@
-// Our customizations to bootstrap
+// Our customizations to bootstrap no here.
 
 @textColor:             @black;
-
-@baseFontSize:			10pt;
\ No newline at end of file
diff --git a/IPython/frontend/html/notebook/static/ipython/notebooks/less/variables.less b/IPython/frontend/html/notebook/static/ipython/notebooks/less/variables.less
index 72cf639..2e45ab9 100644
--- a/IPython/frontend/html/notebook/static/ipython/notebooks/less/variables.less
+++ b/IPython/frontend/html/notebook/static/ipython/notebooks/less/variables.less
@@ -1,3 +1,5 @@
+// Bootstrap customizations specific to this page.
+
 @corner_radius: 4px;
 @notebook_background : white;
 @cell_selected_background: darken(@notebook_background, 2%);
@@ -6,14 +8,4 @@
 @light_border_color: darken(@cell_selected_background, 17%);
 @borderwidth : 1px;
 @fontBaseColor : black;
-
 @baseFontSize:			30pt;
-
-
-
-
-// utilities mixins
-
-.corner-all {
-    border-radius:@corner_radius;
-}
diff --git a/IPython/frontend/html/notebook/templates/base.html b/IPython/frontend/html/notebook/templates/page.html
similarity index 100%
rename from IPython/frontend/html/notebook/templates/base.html
rename to IPython/frontend/html/notebook/templates/page.html