Protect root against system color schemes

System color schemes (in particular, custom themes in Windows and Linux
distros) affect Firefox, IE, and Opera. Normalizing the web site/app's
root background and text color prevents these unwanted settings from
being used. Chrome doesn't apply system-level schemes to websites.

Fix gh-170

CHANGELOG.md

@@ -1,5 +1,8 @@
 == HEAD
 
+* Normalize root `color` and `background` to counter the affects of system
+  color schemes.
+
 == 2.1.0 (January 21, 2013)
 
 * Normalize `text-transform` for `button` and `select`.

normalize.css

@@ -56,15 +56,21 @@ audio:not([controls]) {
    ========================================================================== */
 
 /**
- * 1. Set default font family to sans-serif.
- * 2. Prevent iOS text size adjust after orientation change, without disabling
+ * 1. Prevent system color scheme's background color being used in Firefox, IE,
+ *    and Opera.
+ * 2. Prevent system color scheme's text color being used in Firefox, IE, and
+ *    Opera.
+ * 3. Set default font family to sans-serif.
+ * 4. Prevent iOS text size adjust after orientation change, without disabling
  *    user zoom.
  */
 
 html {
-    font-family: sans-serif; /* 1 */
-    -webkit-text-size-adjust: 100%; /* 2 */
-    -ms-text-size-adjust: 100%; /* 2 */
+    background: #fff; /* 1 */
+    color: #000; /* 2 */
+    font-family: sans-serif; /* 3 */
+    -ms-text-size-adjust: 100%; /* 4 */
+    -webkit-text-size-adjust: 100%; /* 4 */
 }
 
 /**