dark mode with bootstrap complete components

Used https://github.com/vinorodrigues/bootstrap-dark-5/releases/tag/v1.0.0

scss/dark/bootstrap/_root.scss

@@ -0,0 +1,12 @@
+:root {
+  // Custom variable values only support SassScript inside `#{}`.
+  @each $color, $value in $colors-alt {
+    --#{$variable-prefix}#{$color}: #{$value};
+  }
+
+  @each $color, $value in $theme-colors-alt {
+    --#{$variable-prefix}#{$color}: #{$value};
+  }
+
+  --#{$variable-prefix}gradient: #{$gradient-alt};
+}