Fix background for lessons

css/swc.css

+/* Container */
+
+div.container {
+    background: white;
+}
 
 /* Headings */
 h1, h2, h3, h4, h5, h6 {
@@ -262,15 +267,6 @@ blockquote h2{
 }
 
 
-/* Container for page contents. */
-.container-full-width {
-	max-width: none;
-}
-
-.container .jumbotron {
-    padding: 20px;
-}
-
 code {
     color: #333333;
 }