Fix scrollbar style for firefox and all themes

src/app/app.component.sass

@@ -6,7 +6,21 @@ html, body
   height: 100%
 
 
+::ng-deep body
+  scrollbar-color: #aaa #ddd
+  scrollbar-width: thin
+  .dark-theme
+    scrollbar-color: #ddd #666
 
+::ng-deep ::-webkit-scrollbar
+  width: 4px
 
+::ng-deep ::-webkit-scrollbar-track
+  background: #ddd
+  .dark-theme
+    background: #666
 
-
+::ng-deep ::-webkit-scrollbar-thumb
+  background: #aaa
+  .dark-theme
+    background: #ddd

src/styles/mixins.sass

@@ -1,8 +1,5 @@
-::-webkit-scrollbar 
+@mixin gridPosition($rowStart, $rowEnd, $columnStart, $columnEnd)
-  width: 4px
+  grid-row-start: $rowStart
- 
+  grid-row-end: $rowEnd
-::-webkit-scrollbar-track
+  grid-column-start: $columnStart
-  background: #ddd
+  grid-column-end: $columnEnd
-
-::-webkit-scrollbar-thumb 
-  background: #666