clear up show-grid stuff

docs/assets/css/docs.css

@@ -339,8 +339,8 @@ only screen and (     -o-min-device-pixel-ratio: 2/1) {
   min-height: 40px;
   line-height: 40px;
 }
-.show-grid:hover [class*="span"] {
-  background: #ddd;
+.show-grid [class*="span"]:hover {
+  background-color: #ddd;
 }
 .show-grid .show-grid {
   margin-top: 0;

docs/assets/js/application.js

@@ -36,7 +36,7 @@
     // add tipsies to grid for scaffolding
     if ($('#gridSystem').length) {
       $('#gridSystem').tooltip({
-          selector: '.show-grid > div:not(.tooltip)'
+          selector: '.show-grid > [class*="span"]'
         , title: function () { return $(this).width() + 'px' }
       })
     }