Simplify CSS

Add a missing semicolon and simplify padding expression.

Author: jjuhl

doc/custom.css

@@ -22,13 +22,11 @@ body {
 }
 
 div {
-    margin-bottom: 0
+    margin-bottom: 0;
 }
 
 #contents {
-    padding-left: 0;
-    padding-right: 0;
-    padding-bottom: 0;
+    padding: 0;
     margin-left: 0;
     margin-right: 0;
     max-width: 100%;