fix margin of kwant usage examples

Before, the titles stuck out on the left of the main body of text.

content/index.rst

@@ -43,7 +43,7 @@ Kwant.  The tutorial section of `Kwant documentation <doc/1.0/>`_ and the
 explanations (`zipfile of all examples
 <http://downloads.kwant-project.org/examples/kwant-examples-1.0.0.zip>`_).
 
-.. class:: row
+.. class:: row nomargin
 
 Graphene flake
 ..............
@@ -75,7 +75,7 @@ Graphene flake
 
    Taken from the Kwant `plotting tutorial <doc/1.0/tutorial/tutorial6.html>`_.
 
-.. class:: row
+.. class:: row nomargin
 
 Quantum Hall effect
 ...................
@@ -102,7 +102,7 @@ Quantum Hall effect
 
        <object type="image/svg+xml" class="col-md-4 img-responsive" data="qhe-plateaus.svgz">qhe-plateaus.svgz</object>
 
-.. class:: row
+.. class:: row nomargin
 
 3-d system: Majorana states
 ...........................
@@ -123,7 +123,7 @@ Quantum Hall effect
 
    Taken from an unpublished work by S. Mi, A. R. Akhmerov, and M. Wimmer.
 
-.. class:: row
+.. class:: row nomargin
 
 Numerical experiment: flying qubit
 ..................................
@@ -148,7 +148,7 @@ Numerical experiment: flying qubit
 
 .. image:: flying-qubit.png
 
-.. class:: row
+.. class:: row nomargin
 
 Conductance of a Corbino disk in a quantum Hall regime
 ......................................................

themes/kwant/assets/css/custom.css

@@ -35,3 +35,8 @@ footer {
     border-top-color: #EEEEEE;
     border-top-width: medium;
 }
+
+.nomargin {
+    margin-left: 0px;
+    margin-right: 0px;
+}