- update: Bootstrap version to v4.0.0-beta.2

- update: vue-chartjs version to 3.0.0
- refactor: Remove old SCSS variables
- refactor: Breadcrumb Menu styles
- fix: External links issue
- fix: Mobile sidebar-nav height issue

Vue_Starter/scss/bootstrap/mixins/_background-variant.scss

@@ -1,3 +1,5 @@
+// stylelint-disable declaration-no-important
+
 // Contextual backgrounds
 
 @mixin bg-variant($parent, $color) {
@@ -10,3 +12,9 @@
     }
   }
 }
+
+@mixin bg-gradient-variant($parent, $color) {
+  #{$parent} {
+    background: $color linear-gradient(180deg, mix($body-bg, $color, 15%), $color) repeat-x !important;
+  }
+}