Make scrollbars nicer on Firefox

gorge.css

@@ -102,6 +102,8 @@ button {
 #buildings-list {
   overflow-x: hidden;
   overflow-y: scroll;
+  scrollbar-color: #e1e1e1 #888;
+  scrollbar-width: thin;
   max-height: 50vh;
   max-width: 400px;
 }
@@ -288,6 +290,8 @@ button {
   padding-bottom: 100px;
   overflow-x: hidden;
   overflow-y: overlay;
+  scrollbar-color: #e1e1e1 #888;
+  scrollbar-width: thin;
 }
 
 #upgrade-tooltip {