BugFix: import bootstrap _root.scss

src/client/styles/scss/_vendor.scss

@@ -3,6 +3,7 @@
 @import '~bootstrap/scss/variables';
 @import '~bootstrap/scss/mixins';
 @import '~bootstrap/scss/utilities';
+@import '~bootstrap/scss/root';
 
 // increase specificity with ':root' for GROWI theming
 :root {