Available upgrades get a green border

gorge.css

@@ -354,12 +354,16 @@ button {
 
 .upgrade-button:hover {
   background-color: #666;
-  box-shadow: inset 0px 0px 0px 2px red;
+  box-shadow: inset 0px 0px 0px 2px green;
 }
 
-.upgrade-button-inactive {
-  background-color: #222 !important;
-  color: #999 !important;
+.upgrade-button.upgrade-button-inactive {
+  background-color: #222;
+}
+
+.upgrade-button.upgrade-button-inactive:hover {
+  background-color: #333;
+  box-shadow: inset 0px 0px 0px 2px red;
 }
 
 .upgrade-button-inactive .fas {