Updated style.css documentation

src/style.css

@@ -180,10 +180,17 @@
   border-radius: 12px;
 }
 
+/* The .control-center Window.
+ * Can't apply padding and margin so may be easier to use "> box" instead
+ */
 .control-center {
   background: @cc-bg;
 }
 
+/* The first control-center child. May be easier to style this than .control-center */
+.control-center > box {
+}
+
 .control-center-list {
   background: transparent;
 }