consistent use of font sizing tricks

h/css/app.scss

@@ -4,7 +4,7 @@
 @import 'compass/layout/stretching';
 @import 'compass/reset/utilities';
 
-$baseFontSize: 14;
+$baseFontSize: 14px;
 
 @import 'common';
 

h/css/common.scss

@@ -33,7 +33,8 @@ p {
 em { font-style: italic; }
 
 html {
-  font-size: $baseFontSize / 16 * 1em;
+  font-size: $baseFontSize / 16px * 1em;
+  line-height: $baseLineHeight / 16px * 1em;
 }
 
 h1, h2, h3, h4, h5, h6 {

h/css/site.scss

@@ -3,7 +3,7 @@
 @import "compass/css3/images";
 @import "compass/utilities/color";
 
-$baseFontSize: 18;
+$baseFontSize: 18px;
 
 @import "common";