Add dark mode support (#35857)

* Add dark mode to docs

* Minor fix: missing space indentation

* Minor fix: revert utilities/z-index added-in modification

* Remove prev: and next: from doc because extracted to another PR

* Use .bg-body-tertiary in all Utilities > Overflow examples

* fix example

* Fix up spacing examples

* Update box-shadow Sass variables and utilities to auto-adjust to color modes

* Remove unused docs class

* Refactor form styles to use CSS variable for background images on .form-check and .form-switch

* Fix docs selector

* Rename shortcut for clarity

* Heading consistency

* Reintroduce missing 4th grid item in Utilities > Spacing example

* Fix bundlewatch

* .bd-callout* rendering is OK so removing comments in the code

* Update scss/_utilities.scss

Co-authored-by: Julien Déramond <[email protected]>

* Fix gutters example styling

* Fix text colors on background utils docs

* redesign and fix up position marker example, which doesn't show nicely in darkmode but at least isn't broken

* fix some color utils examples

* Deprecate mixin notice

* Deprecate notice for list-group-item-variant() mixin

* Revamp new link CSS vars

* Use map-keys in some each Sass files

* Remove list-group-item-variant mixin ref in sass loop desc

* Display CSS vars scoped to our built-in dark mode

* Revert previous commit

* Fix list group variant link

* Fix typo

* Remove imports of alert/list-group mixins in scss/_mixins.scss

* Small formatting + comments removal in scss/_content.scss

* Fix alert links colors

* fix dropdown border-radius mixin

* fix link color and underline again, this time using CSS var override for color var and fallback value for the underline

* fix colors on docs navbar for dark mode

* remove two changes

* missing ref

* another link underline fix, just use sass vars for link decoration for now

* missing color bg docs, plus move dropdown override to scss

* more changes from review

* fix some examples, drop unused docs navbar styles, update docs navbar color mode to use mixin

* Few fixes around type

- Restored CSS variable for color on headings, this time with a fallback value
- In conjunction, restored and wrapped the default CSS var with a null value check
- Split headings and paragraphs docs in Reboot, elaborated on them

* Restyle custom details > summary element in docs

* Rewrite some migration docs

* fix form checks

* Fix up some navbar styling, tweak docs callout

* Fix select images, mostly for validation styling

* Clean up some migration notes, document some new form control CSS vars, mention new variables-dark in sass docs

* Update site/content/docs/5.2/components/scrollspy.md

Co-authored-by: Julien Déramond <[email protected]>

* Apply suggestions from code review

Co-authored-by: Julien Déramond <[email protected]>

* mention form control css vars in migration guide

* Tweak grid and flex docs background examples

* clarify some docs

* fix some more things

Co-authored-by: Julien Déramond <[email protected]>
Co-authored-by: Julien Déramond <[email protected]>

25 files changed, 584 insertions, 157 deletions

diff --git a/scss/_accordion.scss b/scss/_accordion.scss
index f09601bab..75588a5ad 100644
--- a/scss/_accordion.scss
+++ b/scss/_accordion.scss
@@ -147,3 +147,12 @@
     }
   }
 }
+
+@if $enable-dark-mode {
+  @include color-mode(dark) {
+    .accordion-button::after {
+      --#{$prefix}accordion-btn-icon: #{escape-svg($accordion-button-icon-dark)};
+      --#{$prefix}accordion-btn-active-icon: #{escape-svg($accordion-button-active-icon-dark)};
+    }
+  }
+}
diff --git a/scss/_alert.scss b/scss/_alert.scss
index c8bc91b42..8647851b1 100644
--- a/scss/_alert.scss
+++ b/scss/_alert.scss
@@ -12,6 +12,7 @@
   --#{$prefix}alert-border-color: transparent;
   --#{$prefix}alert-border: #{$alert-border-width} solid var(--#{$prefix}alert-border-color);
   --#{$prefix}alert-border-radius: #{$alert-border-radius};
+  --#{$prefix}alert-link-color: inherit;
   // scss-docs-end alert-css-vars
 
   position: relative;
@@ -32,6 +33,7 @@
 // Provide class for links that match alerts
 .alert-link {
   font-weight: $alert-link-font-weight;
+  color: var(--#{$prefix}alert-link-color);
 }
 
 
@@ -54,18 +56,13 @@
 
 
 // scss-docs-start alert-modifiers
-// Generate contextual modifier classes for colorizing the alert.
-
-@each $state, $value in $theme-colors {
-  $alert-background: shift-color($value, $alert-bg-scale);
-  $alert-border: shift-color($value, $alert-border-scale);
-  $alert-color: shift-color($value, $alert-color-scale);
-
-  @if (contrast-ratio($alert-background, $alert-color) < $min-contrast-ratio) {
-    $alert-color: mix($value, color-contrast($alert-background), abs($alert-color-scale));
-  }
+// Generate contextual modifier classes for colorizing the alert
+@each $state in map-keys($theme-colors) {
   .alert-#{$state} {
-    @include alert-variant($alert-background, $alert-border, $alert-color);
+    --#{$prefix}alert-color: var(--#{$prefix}#{$state}-text);
+    --#{$prefix}alert-bg: var(--#{$prefix}#{$state}-bg-subtle);
+    --#{$prefix}alert-border-color: var(--#{$prefix}#{$state}-border-subtle);
+    --#{$prefix}alert-link-color: var(--#{$prefix}#{$state}-text);
   }
 }
 // scss-docs-end alert-modifiers
diff --git a/scss/_carousel.scss b/scss/_carousel.scss
index 858b83634..ec810f72a 100644
--- a/scss/_carousel.scss
+++ b/scss/_carousel.scss
@@ -210,7 +210,7 @@
 
 // Dark mode carousel
 
-.carousel-dark {
+%carousel-dark {
   .carousel-control-prev-icon,
   .carousel-control-next-icon {
     filter: $carousel-dark-control-icon-filter;
@@ -224,3 +224,15 @@
     color: $carousel-dark-caption-color;
   }
 }
+
+.carousel-dark {
+  @extend %carousel-dark;
+}
+
+@if $enable-dark-mode {
+  @include color-mode(dark) {
+    .carousel {
+      @extend %carousel-dark;
+    }
+  }
+}
diff --git a/scss/_close.scss b/scss/_close.scss
index 423a944db..6f814d0af 100644
--- a/scss/_close.scss
+++ b/scss/_close.scss
@@ -44,6 +44,18 @@
   }
 }
 
-.btn-close-white {
+%btn-close-white {
   filter: var(--#{$prefix}btn-close-white-filter);
 }
+
+.btn-close-white {
+  @extend %btn-close-white;
+}
+
+@if $enable-dark-mode {
+  @include color-mode(dark) {
+    .btn-close {
+      @extend %btn-close-white;
+    }
+  }
+}
diff --git a/scss/_dropdown.scss b/scss/_dropdown.scss
index 8899d25a0..587ebb487 100644
--- a/scss/_dropdown.scss
+++ b/scss/_dropdown.scss
@@ -184,6 +184,7 @@
   white-space: nowrap; // prevent links from randomly breaking onto new lines
   background-color: transparent; // For `<button>`s
   border: 0; // For `<button>`s
+  @include border-radius(var(--#{$prefix}dropdown-item-border-radius, 0));
 
   &:hover,
   &:focus {
diff --git a/scss/_list-group.scss b/scss/_list-group.scss
index c0ec16468..3a976d680 100644
--- a/scss/_list-group.scss
+++ b/scss/_list-group.scss
@@ -180,13 +180,25 @@
 // Add modifier classes to change text and background color on individual items.
 // Organizationally, this must come after the `:hover` states.
 
-@each $state, $value in $theme-colors {
-  $list-group-variant-bg: shift-color($value, $list-group-item-bg-scale);
-  $list-group-variant-color: shift-color($value, $list-group-item-color-scale);
-  @if (contrast-ratio($list-group-variant-bg, $list-group-variant-color) < $min-contrast-ratio) {
-    $list-group-variant-color: mix($value, color-contrast($list-group-variant-bg), abs($list-group-item-color-scale));
-  }
+@each $state in map-keys($theme-colors) {
+  .list-group-item-#{$state} {
+    --#{$prefix}list-group-color: var(--#{$prefix}#{$state}-text);
+    --#{$prefix}list-group-bg: var(--#{$prefix}#{$state}-bg-subtle);
+    --#{$prefix}list-group-border-color: var(--#{$prefix}#{$state}-border-subtle);
+
+    &.list-group-item-action {
+      &:hover,
+      &:focus {
+        --#{$prefix}list-group-action-hover-color: var(--#{$prefix}emphasis-color);
+        --#{$prefix}list-group-action-hover-bg: var(--#{$prefix}#{$state}-border-subtle);
+      }
 
-  @include list-group-item-variant($state, $list-group-variant-bg, $list-group-variant-color);
+      &:active {
+        --#{$prefix}list-group-active-color: var(--#{$prefix}emphasis-color);
+        --#{$prefix}list-group-active-bg: var(--#{$prefix}#{$state}-text);
+        --#{$prefix}list-group-active-border-color: var(--#{$prefix}#{$state}-text);
+      }
+    }
+  }
 }
 // scss-docs-end list-group-modifiers
diff --git a/scss/_maps.scss b/scss/_maps.scss
index 2770a6761..6418a3f6c 100644
--- a/scss/_maps.scss
+++ b/scss/_maps.scss
@@ -6,6 +6,39 @@
 $theme-colors-rgb: map-loop($theme-colors, to-rgb, "$value") !default;
 // scss-docs-end theme-colors-rgb
 
+$theme-colors-text: (
+  "primary": $primary-text,
+  "secondary": $secondary-text,
+  "success": $success-text,
+  "info": $info-text,
+  "warning": $warning-text,
+  "danger": $danger-text,
+  "light": $light-text,
+  "dark": $dark-text,
+) !default;
+
+$theme-colors-bg-subtle: (
+  "primary": $primary-bg-subtle,
+  "secondary": $secondary-bg-subtle,
+  "success": $success-bg-subtle,
+  "info": $info-bg-subtle,
+  "warning": $warning-bg-subtle,
+  "danger": $danger-bg-subtle,
+  "light": $light-bg-subtle,
+  "dark": $dark-bg-subtle,
+) !default;
+
+$theme-colors-border-subtle: (
+  "primary": $primary-border-subtle,
+  "secondary": $secondary-border-subtle,
+  "success": $success-border-subtle,
+  "info": $info-border-subtle,
+  "warning": $warning-border-subtle,
+  "danger": $danger-border-subtle,
+  "light": $light-border-subtle,
+  "dark": $dark-border-subtle,
+) !default;
+
 // Utilities maps
 //
 // Extends the default `$theme-colors` maps to help create our utilities.
@@ -25,6 +58,17 @@ $utilities-text: map-merge(
   )
 ) !default;
 $utilities-text-colors: map-loop($utilities-text, rgba-css-var, "$key", "text") !default;
+
+$utilities-text-emphasis-colors: (
+  "primary-emphasis": var(--#{$prefix}primary-text),
+  "secondary-emphasis": var(--#{$prefix}secondary-text),
+  "success-emphasis": var(--#{$prefix}success-text),
+  "info-emphasis": var(--#{$prefix}info-text),
+  "warning-emphasis": var(--#{$prefix}warning-text),
+  "danger-emphasis": var(--#{$prefix}danger-text),
+  "light-emphasis": var(--#{$prefix}light-text),
+  "dark-emphasis": var(--#{$prefix}dark-text)
+) !default;
 // scss-docs-end utilities-text-colors
 
 // scss-docs-start utilities-bg-colors
@@ -37,6 +81,18 @@ $utilities-bg: map-merge(
   )
 ) !default;
 $utilities-bg-colors: map-loop($utilities-bg, rgba-css-var, "$key", "bg") !default;
+
+$utilities-bg-subtle: (
+  "primary-subtle": var(--#{$prefix}primary-bg-subtle),
+  "secondary-subtle": var(--#{$prefix}secondary-bg-subtle),
+  "success-subtle": var(--#{$prefix}success-bg-subtle),
+  "info-subtle": var(--#{$prefix}info-bg-subtle),
+  "warning-subtle": var(--#{$prefix}warning-bg-subtle),
+  "danger-subtle": var(--#{$prefix}danger-bg-subtle),
+  "light-subtle": var(--#{$prefix}light-bg-subtle),
+  "dark-subtle": var(--#{$prefix}dark-bg-subtle)
+) !default;
+// $utilities-bg-subtle-colors: map-loop($utilities-bg-subtle, rgba-css-var, "$key", "bg") !default;
 // scss-docs-end utilities-bg-colors
 
 // scss-docs-start utilities-border-colors
@@ -47,6 +103,17 @@ $utilities-border: map-merge(
   )
 ) !default;
 $utilities-border-colors: map-loop($utilities-border, rgba-css-var, "$key", "border") !default;
+
+$utilities-border-subtle: (
+  "primary-subtle": var(--#{$prefix}primary-border-subtle),
+  "secondary-subtle": var(--#{$prefix}secondary-border-subtle),
+  "success-subtle": var(--#{$prefix}success-border-subtle),
+  "info-subtle": var(--#{$prefix}info-border-subtle),
+  "warning-subtle": var(--#{$prefix}warning-border-subtle),
+  "danger-subtle": var(--#{$prefix}danger-border-subtle),
+  "light-subtle": var(--#{$prefix}light-border-subtle),
+  "dark-subtle": var(--#{$prefix}dark-border-subtle)
+) !default;
 // scss-docs-end utilities-border-colors
 
 $negative-spacers: if($enable-negative-margins, negativify-map($spacers), null) !default;
diff --git a/scss/_mixins.scss b/scss/_mixins.scss
index af1f74f72..e1e130b16 100644
--- a/scss/_mixins.scss
+++ b/scss/_mixins.scss
@@ -10,6 +10,7 @@
 
 // Helpers
 @import "mixins/breakpoints";
+@import "mixins/color-mode";
 @import "mixins/color-scheme";
 @import "mixins/image";
 @import "mixins/resize";
@@ -21,13 +22,11 @@
 @import "mixins/utilities";
 
 // Components
-@import "mixins/alert";
 @import "mixins/backdrop";
 @import "mixins/buttons";
 @import "mixins/caret";
 @import "mixins/pagination";
 @import "mixins/lists";
-@import "mixins/list-group";
 @import "mixins/forms";
 @import "mixins/table-variants";
 
diff --git a/scss/_navbar.scss b/scss/_navbar.scss
index 599b055eb..b65355f44 100644
--- a/scss/_navbar.scss
+++ b/scss/_navbar.scss
@@ -276,3 +276,11 @@
   --#{$prefix}navbar-toggler-icon-bg: #{escape-svg($navbar-dark-toggler-icon-bg)};
   // scss-docs-end navbar-dark-css-vars
 }
+
+@if $enable-dark-mode {
+  @include color-mode(dark) {
+    .navbar {
+      --#{$prefix}navbar-toggler-icon-bg: #{escape-svg($navbar-dark-toggler-icon-bg)};
+    }
+  }
+}
diff --git a/scss/_pagination.scss b/scss/_pagination.scss
index cf4db3c36..ba83d3578 100644
--- a/scss/_pagination.scss
+++ b/scss/_pagination.scss
@@ -75,7 +75,7 @@
     margin-left: $pagination-margin-start;
   }
 
-  @if $pagination-margin-start == ($pagination-border-width * -1) {
+  @if $pagination-margin-start == calc($pagination-border-width * -1) {
     &:first-child {
       .page-link {
         @include border-start-radius(var(--#{$prefix}pagination-border-radius));
diff --git a/scss/_reboot.scss b/scss/_reboot.scss
index 8ac790399..305740587 100644
--- a/scss/_reboot.scss
+++ b/scss/_reboot.scss
@@ -87,7 +87,7 @@ hr {
   font-style: $headings-font-style;
   font-weight: $headings-font-weight;
   line-height: $headings-line-height;
-  color: $headings-color;
+  color: var(--#{$prefix}heading-color, inherit);
 }
 
 h1 {
@@ -241,11 +241,11 @@ sup { top: -.5em; }
 // Links
 
 a {
-  color: var(--#{$prefix}link-color);
+  color: rgba(var(--#{$prefix}link-color-rgb), var(--#{$prefix}link-opacity, 1));
   text-decoration: $link-decoration;
 
   &:hover {
-    color: var(--#{$prefix}link-hover-color);
+    --#{$prefix}link-color-rgb: var(--#{$prefix}link-hover-color-rgb);
     text-decoration: $link-hover-decoration;
   }
 }
diff --git a/scss/_root.scss b/scss/_root.scss
index 60e15152f..19cc06696 100644
--- a/scss/_root.scss
+++ b/scss/_root.scss
@@ -1,4 +1,5 @@
-:root {
+:root,
+[data-bs-theme="light"] {
   // Note: Custom variable values only support SassScript inside `#{}`.
 
   // Colors
@@ -21,6 +22,18 @@
     --#{$prefix}#{$color}-rgb: #{$value};
   }
 
+  @each $color, $value in $theme-colors-text {
+    --#{$prefix}#{$color}-text: #{$value};
+  }
+
+  @each $color, $value in $theme-colors-bg-subtle {
+    --#{$prefix}#{$color}-bg-subtle: #{$value};
+  }
+
+  @each $color, $value in $theme-colors-border-subtle {
+    --#{$prefix}#{$color}-border-subtle: #{$value};
+  }
+
   --#{$prefix}white-rgb: #{to-rgb($white)};
   --#{$prefix}black-rgb: #{to-rgb($black)};
   --#{$prefix}body-color-rgb: #{to-rgb($body-color)};
@@ -44,12 +57,45 @@
   --#{$prefix}body-font-weight: #{$font-weight-base};
   --#{$prefix}body-line-height: #{$line-height-base};
   --#{$prefix}body-color: #{$body-color};
+
+  --#{$prefix}emphasis-color: #{$body-emphasis-color};
+  --#{$prefix}emphasis-color-rgb: #{to-rgb($body-emphasis-color)};
+
+  --#{$prefix}secondary-color: #{$body-secondary-color};
+  --#{$prefix}secondary-color-rgb: #{to-rgb($body-secondary-color)};
+  --#{$prefix}secondary-bg: #{$body-secondary-bg};
+  --#{$prefix}secondary-bg-rgb: #{to-rgb($body-secondary-bg)};
+
+  --#{$prefix}tertiary-color: #{$body-tertiary-color};
+  --#{$prefix}tertiary-color-rgb: #{to-rgb($body-tertiary-color)};
+  --#{$prefix}tertiary-bg: #{$body-tertiary-bg};
+  --#{$prefix}tertiary-bg-rgb: #{to-rgb($body-tertiary-bg)};
+
   @if $body-text-align != null {
     --#{$prefix}body-text-align: #{$body-text-align};
   }
   --#{$prefix}body-bg: #{$body-bg};
+  --#{$prefix}body-bg-rgb: #{to-rgb($body-bg)};
   // scss-docs-end root-body-variables
 
+  @if $headings-color != null {
+    --#{$prefix}heading-color: #{$headings-color};
+  }
+
+  --#{$prefix}link-color: #{$link-color};
+  --#{$prefix}link-color-rgb: #{to-rgb($link-color)};
+  --#{$prefix}link-decoration: #{$link-decoration};
+
+  --#{$prefix}link-hover-color: #{$link-hover-color};
+  --#{$prefix}link-hover-color-rgb: #{to-rgb($link-hover-color)};
+
+  @if $link-hover-decoration != null {
+    --#{$prefix}link-hover-decoration: #{$link-hover-decoration};
+  }
+
+  --#{$prefix}code-color: #{$code-color};
+  --#{$prefix}highlight-bg: #{$mark-bg};
+
   // scss-docs-start root-border-var
   --#{$prefix}border-width: #{$border-width};
   --#{$prefix}border-style: #{$border-style};
@@ -64,10 +110,17 @@
   --#{$prefix}border-radius-pill: #{$border-radius-pill};
   // scss-docs-end root-border-var
 
-  --#{$prefix}link-color: #{$link-color};
-  --#{$prefix}link-hover-color: #{$link-hover-color};
+  --#{$prefix}box-shadow: #{$box-shadow};
+  --#{$prefix}box-shadow-sm: #{$box-shadow-sm};
+  --#{$prefix}box-shadow-lg: #{$box-shadow-lg};
+  --#{$prefix}box-shadow-inset: #{$box-shadow-inset};
 
-  --#{$prefix}code-color: #{$code-color};
+  --#{$prefix}emphasis-color: #{$emphasis-color};
+
+  // scss-docs-start form-control-vars
+  --#{$prefix}form-control-bg: var(--#{$prefix}body-bg);
+  --#{$prefix}form-control-disabled-bg: var(--#{$prefix}secondary-bg);
+  // scss-docs-end form-control-vars
 
   --#{$prefix}highlight-bg: #{$mark-bg};
 
@@ -75,3 +128,68 @@
     --#{$prefix}breakpoint-#{$name}: #{$value};
   }
 }
+
+@if $enable-dark-mode {
+  @include color-mode(dark) {
+    // scss-docs-start root-dark-mode-vars
+    --#{$prefix}body-color: #{$body-color-dark};
+    --#{$prefix}body-color-rgb: #{to-rgb($body-color-dark)};
+    --#{$prefix}body-bg: #{$body-bg-dark};
+    --#{$prefix}body-bg-rgb: #{to-rgb($body-bg-dark)};
+
+    --#{$prefix}emphasis-color: #{$body-emphasis-color-dark};
+    --#{$prefix}emphasis-color-rgb: #{to-rgb($body-emphasis-color-dark)};
+
+    --#{$prefix}secondary-color: #{$body-secondary-color-dark};
+    --#{$prefix}secondary-color-rgb: #{to-rgb($body-secondary-color-dark)};
+    --#{$prefix}secondary-bg: #{$body-secondary-bg-dark};
+    --#{$prefix}secondary-bg-rgb: #{to-rgb($body-secondary-bg-dark)};
+
+    --#{$prefix}tertiary-color: #{$body-tertiary-color-dark};
+    --#{$prefix}tertiary-color-rgb: #{to-rgb($body-tertiary-color-dark)};
+    --#{$prefix}tertiary-bg: #{$body-tertiary-bg-dark};
+    --#{$prefix}tertiary-bg-rgb: #{to-rgb($body-tertiary-bg-dark)};
+
+    --#{$prefix}emphasis-color: #{$emphasis-color-dark};
+
+    --#{$prefix}primary-text: #{$primary-text-dark};
+    --#{$prefix}secondary-text: #{$secondary-text-dark};
+    --#{$prefix}success-text: #{$success-text-dark};
+    --#{$prefix}info-text: #{$info-text-dark};
+    --#{$prefix}warning-text: #{$warning-text-dark};
+    --#{$prefix}danger-text: #{$danger-text-dark};
+    --#{$prefix}light-text: #{$light-text-dark};
+    --#{$prefix}dark-text: #{$dark-text-dark};
+
+    --#{$prefix}primary-bg-subtle: #{$primary-bg-subtle-dark};
+    --#{$prefix}secondary-bg-subtle: #{$secondary-bg-subtle-dark};
+    --#{$prefix}success-bg-subtle: #{$success-bg-subtle-dark};
+    --#{$prefix}info-bg-subtle: #{$info-bg-subtle-dark};
+    --#{$prefix}warning-bg-subtle: #{$warning-bg-subtle-dark};
+    --#{$prefix}danger-bg-subtle: #{$danger-bg-subtle-dark};
+    --#{$prefix}light-bg-subtle: #{$light-bg-subtle-dark};
+    --#{$prefix}dark-bg-subtle: #{$dark-bg-subtle-dark};
+
+    --#{$prefix}primary-border-subtle: #{$primary-border-subtle-dark};
+    --#{$prefix}secondary-border-subtle: #{$secondary-border-subtle-dark};
+    --#{$prefix}success-border-subtle: #{$success-border-subtle-dark};
+    --#{$prefix}info-border-subtle: #{$info-border-subtle-dark};
+    --#{$prefix}warning-border-subtle: #{$warning-border-subtle-dark};
+    --#{$prefix}danger-border-subtle: #{$danger-border-subtle-dark};
+    --#{$prefix}light-border-subtle: #{$light-border-subtle-dark};
+    --#{$prefix}dark-border-subtle: #{$dark-border-subtle-dark};
+
+    --#{$prefix}heading-color: #{$headings-color-dark};
+
+    --#{$prefix}link-color: #{$link-color-dark};
+    --#{$prefix}link-hover-color: #{$link-hover-color-dark};
+    --#{$prefix}link-color-rgb: #{to-rgb($link-color-dark)};
+    --#{$prefix}link-hover-color-rgb: #{to-rgb($link-hover-color-dark)};
+
+    --#{$prefix}code-color: #{$code-color-dark};
+
+    --#{$prefix}border-color: #{$border-color-dark};
+    --#{$prefix}border-color-translucent: #{$border-color-translucent-dark};
+    // scss-docs-end root-dark-mode-vars
+  }
+}
diff --git a/scss/_utilities.scss b/scss/_utilities.scss
index a8c8b89a7..4c2c39dd7 100644
--- a/scss/_utilities.scss
+++ b/scss/_utilities.scss
@@ -163,6 +163,11 @@ $utilities: map-merge(
       ),
       values: $utilities-border-colors
     ),
+    "subtle-border-color": (
+      property: border-color,
+      class: border,
+      values: $utilities-border-subtle
+    ),
     "border-width": (
       css-var: true,
       css-variable-name: border-width,
@@ -570,9 +575,12 @@ $utilities: map-merge(
       values: map-merge(
         $utilities-text-colors,
         (
-          "muted": $text-muted,
+          "muted": $text-muted, // deprecated
           "black-50": rgba($black, .5), // deprecated
           "white-50": rgba($white, .5), // deprecated
+          "body-secondary": var(--#{$prefix}secondary-color),
+          "body-tertiary": var(--#{$prefix}tertiary-color),
+          "body-emphasis": var(--#{$prefix}emphasis-color),
           "reset": inherit,
         )
       )
@@ -587,6 +595,11 @@ $utilities: map-merge(
         100: 1
       )
     ),
+    "text-color": (
+      property: color,
+      class: text,
+      values: $utilities-text-emphasis-colors
+    ),
     // scss-docs-end utils-color
     // scss-docs-start utils-bg-color
     "background-color": (
@@ -598,7 +611,10 @@ $utilities: map-merge(
       values: map-merge(
         $utilities-bg-colors,
         (
-          "transparent": transparent
+          "transparent": transparent,
+          "body-secondary": rgba(var(--#{$prefix}secondary-bg-rgb), var(--#{$prefix}bg-opacity)),
+          "body-tertiary": rgba(var(--#{$prefix}tertiary-bg-rgb), var(--#{$prefix}bg-opacity)),
+          "body-emphasis": rgba(var(--#{$prefix}emphasis-bg-rgb), var(--#{$prefix}bg-opacity)),
         )
       )
     ),
@@ -613,6 +629,11 @@ $utilities: map-merge(
         100: 1
       )
     ),
+    "subtle-background-color": (
+      property: background-color,
+      class: bg,
+      values: $utilities-bg-subtle
+    ),
     // scss-docs-end utils-bg-color
     "gradient": (
       property: background-image,
diff --git a/scss/_variables-dark.scss b/scss/_variables-dark.scss
new file mode 100644
index 000000000..9a3874fdc
--- /dev/null
+++ b/scss/_variables-dark.scss
@@ -0,0 +1,70 @@
+// Dark color mode variables
+//
+// Custom variables for the `[data-bs-theme="dark"]` theme. Use this as a starting point for your own custom color modes by creating a new theme-specific file like `_variables-dark.scss` and adding the variables you need.
+
+//
+// Global colors
+//
+
+// scss-docs-start sass-dark-mode-vars
+$primary-text-dark:                 $blue-300 !default;
+$secondary-text-dark:               $gray-300 !default;
+$success-text-dark:                 $green-300 !default;
+$info-text-dark:                    $cyan-300 !default;
+$warning-text-dark:                 $yellow-300 !default;
+$danger-text-dark:                  $red-300 !default;
+$light-text-dark:                   $gray-100 !default;
+$dark-text-dark:                    $gray-300 !default;
+
+$primary-bg-subtle-dark:            $blue-900 !default;
+$secondary-bg-subtle-dark:          $gray-900 !default;
+$success-bg-subtle-dark:            $green-900 !default;
+$info-bg-subtle-dark:               $cyan-900 !default;
+$warning-bg-subtle-dark:            $yellow-900 !default;
+$danger-bg-subtle-dark:             $red-900 !default;
+$light-bg-subtle-dark:              $gray-800 !default;
+$dark-bg-subtle-dark:               mix($gray-800, $black) !default;
+
+$primary-border-subtle-dark:        $blue-700 !default;
+$secondary-border-subtle-dark:      $gray-700 !default;
+$success-border-subtle-dark:        $green-700 !default;
+$info-border-subtle-dark:           $cyan-800 !default;
+$warning-border-subtle-dark:        $yellow-800 !default;
+$danger-border-subtle-dark:         $red-700 !default;
+$light-border-subtle-dark:          $gray-700 !default;
+$dark-border-subtle-dark:           $gray-800 !default;
+
+$body-color-dark:                   $gray-500 !default;
+$body-bg-dark:                      $gray-900 !default;
+$body-emphasis-color-dark:          $gray-100 !default;
+$body-secondary-color-dark:         rgba($body-color-dark, .75) !default;
+$body-secondary-bg-dark:            $gray-800 !default;
+$body-tertiary-color-dark:          rgba($body-color-dark, .5) !default;
+$body-tertiary-bg-dark:             mix($gray-800, $gray-900, 50%) !default;
+$emphasis-color-dark:               $white !default;
+$border-color-dark:                 $gray-700 !default;
+$border-color-translucent-dark:     rgba($white, .15) !default;
+$headings-color-dark:               #fff !default;
+$link-color-dark:                   $blue-300 !default;
+$link-hover-color-dark:             $blue-200 !default;
+$code-color-dark:                   $pink-300 !default;
+
+
+//
+// Forms
+//
+
+$form-select-indicator-color-dark:  $body-color-dark !default;
+$form-select-indicator-dark:        url("data:image/svg+xml,<svg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 16 16'><path fill='none' stroke='#{$form-select-indicator-color-dark}' stroke-linecap='round' stroke-linejoin='round' stroke-width='2' d='m2 5 6 6 6-6'/></svg>") !default;
+
+$form-switch-color-dark:            rgba($white, .25) !default;
+$form-switch-bg-image-dark:         url("data:image/svg+xml,<svg xmlns='http://www.w3.org/2000/svg' viewBox='-4 -4 8 8'><circle r='3' fill='#{$form-switch-color-dark}'/></svg>") !default;
+
+
+//
+// Accordion
+//
+
+$accordion-button-icon-dark:         url("data:image/svg+xml,<svg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 16 16' fill='#{$primary-text-dark}'><path fill-rule='evenodd' d='M1.646 4.646a.5.5 0 0 1 .708 0L8 10.293l5.646-5.647a.5.5 0 0 1 .708.708l-6 6a.5.5 0 0 1-.708 0l-6-6a.5.5 0 0 1 0-.708z'/></svg>") !default;
+$accordion-button-active-icon-dark:  url("data:image/svg+xml,<svg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 16 16' fill='#{$primary-text-dark}'><path fill-rule='evenodd' d='M1.646 4.646a.5.5 0 0 1 .708 0L8 10.293l5.646-5.647a.5.5 0 0 1 .708.708l-6 6a.5.5 0 0 1-.708 0l-6-6a.5.5 0 0 1 0-.708z'/></svg>") !default;
+// scss-docs-end sass-dark-mode-vars
diff --git a/scss/_variables.scss b/scss/_variables.scss
index 1c23cf2d9..7c934825c 100644
--- a/scss/_variables.scss
+++ b/scss/_variables.scss
@@ -321,6 +321,33 @@ $theme-colors: (
 ) !default;
 // scss-docs-end theme-colors-map
 
+$primary-text:            $blue-600 !default;
+$secondary-text:          $gray-600 !default;
+$success-text:            $green-600 !default;
+$info-text:               $cyan-700 !default;
+$warning-text:            $yellow-700 !default;
+$danger-text:             $red-600 !default;
+$light-text:              $gray-600 !default;
+$dark-text:               $gray-700 !default;
+
+$primary-bg-subtle:       $blue-100 !default;
+$secondary-bg-subtle:     $gray-100 !default;
+$success-bg-subtle:       $green-100 !default;
+$info-bg-subtle:          $cyan-100 !default;
+$warning-bg-subtle:       $yellow-100 !default;
+$danger-bg-subtle:        $red-100 !default;
+$light-bg-subtle:         mix($gray-100, $white) !default;
+$dark-bg-subtle:          $gray-400 !default;
+
+$primary-border-subtle:   $blue-200 !default;
+$secondary-border-subtle: $gray-200 !default;
+$success-border-subtle:   $green-200 !default;
+$info-border-subtle:      $cyan-200 !default;
+$warning-border-subtle:   $yellow-200 !default;
+$danger-border-subtle:    $red-200 !default;
+$light-border-subtle:     $gray-200 !default;
+$dark-border-subtle:      $gray-500 !default;
+
 // Characters which are escaped by the escape-svg function
 $escaped-characters: (
   ("<", "%3c"),
@@ -351,6 +378,9 @@ $enable-negative-margins:     false !default;
 $enable-deprecation-messages: true !default;
 $enable-important-utilities:  true !default;
 
+$enable-dark-mode:            true !default;
+$color-mode-type:             data !default;
+
 // Prefix for :root CSS variables
 
 $variable-prefix:             bs- !default; // Deprecated in v5.2.0 for the shorter `$prefix`
@@ -398,9 +428,19 @@ $position-values: (
 //
 // Settings for the `<body>` element.
 
-$body-bg:                   $white !default;
-$body-color:                $gray-900 !default;
 $body-text-align:           null !default;
+$body-color:                $gray-900 !default;
+$body-bg:                   $white !default;
+
+$body-emphasis-color:       $black !default;
+
+$body-secondary-color:      rgba($body-color, .75) !default;
+$body-secondary-bg:         $gray-200 !default;
+
+$body-tertiary-color:       rgba($body-color, .5) !default;
+$body-tertiary-bg:          $gray-100 !default;
+
+$emphasis-color:            $black !default;
 
 // Links
 //
@@ -485,7 +525,6 @@ $border-widths: (
   4: 4px,
   5: 5px
 ) !default;
-
 $border-style:                solid !default;
 $border-color:                $gray-300 !default;
 $border-color-translucent:    rgba($black, .175) !default;
@@ -501,10 +540,10 @@ $border-radius-pill:          50rem !default;
 // scss-docs-end border-radius-variables
 
 // scss-docs-start box-shadow-variables
-$box-shadow:                  0 .5rem 1rem rgba($black, .15) !default;
-$box-shadow-sm:               0 .125rem .25rem rgba($black, .075) !default;
-$box-shadow-lg:               0 1rem 3rem rgba($black, .175) !default;
-$box-shadow-inset:            inset 0 1px 2px rgba($black, .075) !default;
+$box-shadow:                  0 .5rem 1rem rgba(var(--#{$prefix}body-color-rgb), .15) !default;
+$box-shadow-sm:               0 .125rem .25rem rgba(var(--#{$prefix}body-color-rgb), .075) !default;
+$box-shadow-lg:               0 1rem 3rem rgba(var(--#{$prefix}body-color-rgb), .175) !default;
+$box-shadow-inset:            inset 0 1px 2px rgba(var(--#{$prefix}body-color-rgb), .075) !default;
 // scss-docs-end box-shadow-variables
 
 $component-active-color:      $white !default;
@@ -619,7 +658,7 @@ $small-font-size:             .875em !default;
 
 $sub-sup-font-size:           .75em !default;
 
-$text-muted:                  $gray-600 !default;
+$text-muted:                  var(--#{$prefix}secondary-color) !default;
 
 $initialism-font-size:        $small-font-size !default;
 
@@ -825,13 +864,13 @@ $input-padding-y-lg:                    $input-btn-padding-y-lg !default;
 $input-padding-x-lg:                    $input-btn-padding-x-lg !default;
 $input-font-size-lg:                    $input-btn-font-size-lg !default;
 
-$input-bg:                              $body-bg !default;
+$input-bg:                              var(--#{$prefix}form-control-bg) !default;
 $input-disabled-color:                  null !default;
-$input-disabled-bg:                     $gray-200 !default;
+$input-disabled-bg:                     var(--#{$prefix}form-control-disabled-bg) !default;
 $input-disabled-border-color:           null !default;
 
-$input-color:                           $body-color !default;
-$input-border-color:                    $gray-400 !default;
+$input-color:                           var(--#{$prefix}body-color) !default;
+$input-border-color:                    var(--#{$prefix}border-color) !default; //$gray-400
 $input-border-width:                    $input-btn-border-width !default;
 $input-box-shadow:                      $box-shadow-inset !default;
 
@@ -845,8 +884,8 @@ $input-focus-color:                     $input-color !default;
 $input-focus-width:                     $input-btn-focus-width !default;
 $input-focus-box-shadow:                $input-btn-focus-box-shadow !default;
 
-$input-placeholder-color:               $gray-600 !default;
-$input-plaintext-color:                 $body-color !default;
+$input-placeholder-color:               var(--#{$prefix}secondary-color) !default;
+$input-plaintext-color:                 var(--#{$prefix}body-color) !default;
 
 $input-height-border:                   calc($input-border-width * 2) !default; // stylelint-disable-line function-disallowed-list
 
@@ -875,7 +914,7 @@ $form-check-transition:                   null !default;
 $form-check-input-active-filter:          brightness(90%) !default;
 
 $form-check-input-bg:                     $input-bg !default;
-$form-check-input-border:                 1px solid rgba($black, .25) !default;
+$form-check-input-border:                 var(--#{$prefix}border-width) solid var(--#{$prefix}border-color) !default;
 $form-check-input-border-radius:          .25em !default;
 $form-check-radio-border-radius:          50% !default;
 $form-check-input-focus-border:           $input-focus-border-color !default;
@@ -920,7 +959,7 @@ $input-group-addon-padding-y:           $input-padding-y !default;
 $input-group-addon-padding-x:           $input-padding-x !default;
 $input-group-addon-font-weight:         $input-font-weight !default;
 $input-group-addon-color:               $input-color !default;
-$input-group-addon-bg:                  $gray-200 !default;
+$input-group-addon-bg:                  var(--#{$prefix}tertiary-bg) !default;
 $input-group-addon-border-color:        $input-border-color !default;
 // scss-docs-end input-group-variables
 
@@ -935,7 +974,7 @@ $form-select-line-height:           $input-line-height !default;
 $form-select-color:                 $input-color !default;
 $form-select-bg:                    $input-bg !default;
 $form-select-disabled-color:        null !default;
-$form-select-disabled-bg:           $gray-200 !default;
+$form-select-disabled-bg:           $input-disabled-bg !default;
 $form-select-disabled-border-color: $input-disabled-border-color !default;
 $form-select-bg-position:           right $form-select-padding-x center !default;
 $form-select-bg-size:               16px 12px !default; // In pixels because image dimensions
@@ -972,7 +1011,7 @@ $form-select-transition:          $input-transition !default;
 $form-range-track-width:          100% !default;
 $form-range-track-height:         .5rem !default;
 $form-range-track-cursor:         pointer !default;
-$form-range-track-bg:             $gray-300 !default;
+$form-range-track-bg:             var(--#{$prefix}tertiary-bg) !default;
 $form-range-track-border-radius:  1rem !default;
 $form-range-track-box-shadow:     $box-shadow-inset !default;
 
@@ -985,14 +1024,14 @@ $form-range-thumb-box-shadow:              0 .1rem .25rem rgba($black, .1) !defa
 $form-range-thumb-focus-box-shadow:        0 0 0 1px $body-bg, $input-focus-box-shadow !default;
 $form-range-thumb-focus-box-shadow-width:  $input-focus-width !default; // For focus box shadow issue in Edge
 $form-range-thumb-active-bg:               tint-color($component-active-bg, 70%) !default;
-$form-range-thumb-disabled-bg:             $gray-500 !default;
+$form-range-thumb-disabled-bg:             var(--#{$prefix}secondary-color) !default;
 $form-range-thumb-transition:              background-color .15s ease-in-out, border-color .15s ease-in-out, box-shadow .15s ease-in-out !default;
 // scss-docs-end form-range-variables
 
 // scss-docs-start form-file-variables
 $form-file-button-color:          $input-color !default;
-$form-file-button-bg:             $input-group-addon-bg !default;
-$form-file-button-hover-bg:       shade-color($form-file-button-bg, 5%) !default;
+$form-file-button-bg:             var(--#{$prefix}tertiary-bg) !default;
+$form-file-button-hover-bg:       var(--#{$prefix}secondary-bg) !default;
 // scss-docs-end form-file-variables
 
 // scss-docs-start form-floating-variables
@@ -1027,12 +1066,20 @@ $form-feedback-icon-invalid:        url("data:image/svg+xml,<svg xmlns='http://w
 // scss-docs-start form-validation-states
 $form-validation-states: (
   "valid": (
-    "color": $form-feedback-valid-color,
-    "icon": $form-feedback-icon-valid
+    "color": var(--#{$prefix}success-text),
+    "icon": $form-feedback-icon-valid,
+    "tooltip-color": #fff,
+    "tooltip-bg-color": var(--#{$prefix}success),
+    "focus-box-shadow": 0 0 $input-btn-focus-blur $input-focus-width rgba(var(--#{$prefix}success-rgb), $input-btn-focus-color-opacity),
+    "border-color": var(--#{$prefix}success),
   ),
   "invalid": (
-    "color": $form-feedback-invalid-color,
-    "icon": $form-feedback-icon-invalid
+    "color": var(--#{$prefix}danger-text),
+    "icon": $form-feedback-icon-invalid,
+    "tooltip-color": #fff,
+    "tooltip-bg-color": var(--#{$prefix}danger),
+    "focus-box-shadow": 0 0 $input-btn-focus-blur $input-focus-width rgba(var(--#{$prefix}danger-rgb), $input-btn-focus-color-opacity),
+    "border-color": var(--#{$prefix}danger),
   )
 ) !default;
 // scss-docs-end form-validation-states
@@ -1076,15 +1123,15 @@ $nav-link-font-weight:              null !default;
 $nav-link-color:                    var(--#{$prefix}link-color) !default;
 $nav-link-hover-color:              var(--#{$prefix}link-hover-color) !default;
 $nav-link-transition:               color .15s ease-in-out, background-color .15s ease-in-out, border-color .15s ease-in-out !default;
-$nav-link-disabled-color:           $gray-600 !default;
+$nav-link-disabled-color:           var(--#{$prefix}secondary-color) !default;
 
-$nav-tabs-border-color:             $gray-300 !default;
+$nav-tabs-border-color:             var(--#{$prefix}border-color) !default;
 $nav-tabs-border-width:             var(--#{$prefix}border-width) !default;
-$nav-tabs-border-radius:            $border-radius !default;
-$nav-tabs-link-hover-border-color:  $gray-200 $gray-200 $nav-tabs-border-color !default;
-$nav-tabs-link-active-color:        $gray-700 !default;
-$nav-tabs-link-active-bg:           $body-bg !default;
-$nav-tabs-link-active-border-color: $gray-300 $gray-300 $nav-tabs-link-active-bg !default;
+$nav-tabs-border-radius:            var(--#{$prefix}border-radius) !default;
+$nav-tabs-link-hover-border-color:  var(--#{$prefix}secondary-bg) var(--#{$prefix}secondary-bg) $nav-tabs-border-color !default;
+$nav-tabs-link-active-color:        var(--#{$prefix}emphasis-color) !default;
+$nav-tabs-link-active-bg:           var(--#{$prefix}body-bg) !default;
+$nav-tabs-link-active-border-color: var(--#{$prefix}border-color) var(--#{$prefix}border-color) $nav-tabs-link-active-bg !default;
 
 $nav-pills-border-radius:           $border-radius !default;
 $nav-pills-link-active-color:       $component-active-color !default;
@@ -1114,12 +1161,12 @@ $navbar-toggler-border-radius:      $btn-border-radius !default;
 $navbar-toggler-focus-width:        $btn-focus-width !default;
 $navbar-toggler-transition:         box-shadow .15s ease-in-out !default;
 
-$navbar-light-color:                rgba($black, .55) !default;
-$navbar-light-hover-color:          rgba($black, .7) !default;
-$navbar-light-active-color:         rgba($black, .9) !default;
-$navbar-light-disabled-color:       rgba($black, .3) !default;
-$navbar-light-toggler-icon-bg:      url("data:image/svg+xml,<svg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 30 30'><path stroke='#{$navbar-light-color}' stroke-linecap='round' stroke-miterlimit='10' stroke-width='2' d='M4 7h22M4 15h22M4 23h22'/></svg>") !default;
-$navbar-light-toggler-border-color: rgba($black, .1) !default;
+$navbar-light-color:                rgba(var(--#{$prefix}emphasis-color-rgb), .65) !default;
+$navbar-light-hover-color:          rgba(var(--#{$prefix}emphasis-color-rgb), .8) !default;
+$navbar-light-active-color:         rgba(var(--#{$prefix}emphasis-color-rgb), 1) !default;
+$navbar-light-disabled-color:       rgba(var(--#{$prefix}emphasis-color-rgb), .3) !default;
+$navbar-light-toggler-icon-bg:      url("data:image/svg+xml,<svg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 30 30'><path stroke='#{rgba($body-color, .75)}' stroke-linecap='round' stroke-miterlimit='10' stroke-width='2' d='M4 7h22M4 15h22M4 23h22'/></svg>") !default;
+$navbar-light-toggler-border-color: rgba(var(--#{$prefix}emphasis-color-rgb), .15) !default;
 $navbar-light-brand-color:          $navbar-light-active-color !default;
 $navbar-light-brand-hover-color:    $navbar-light-active-color !default;
 // scss-docs-end navbar-variables
@@ -1146,8 +1193,8 @@ $dropdown-padding-x:                0 !default;
 $dropdown-padding-y:                .5rem !default;
 $dropdown-spacer:                   .125rem !default;
 $dropdown-font-size:                $font-size-base !default;
-$dropdown-color:                    $body-color !default;
-$dropdown-bg:                       $white !default;
+$dropdown-color:                    var(--#{$prefix}body-color) !default;
+$dropdown-bg:                       var(--#{$prefix}body-bg) !default;
 $dropdown-border-color:             var(--#{$prefix}border-color-translucent) !default;
 $dropdown-border-radius:            $border-radius !default;
 $dropdown-border-width:             var(--#{$prefix}border-width) !default;
@@ -1156,9 +1203,9 @@ $dropdown-divider-bg:               $dropdown-border-color !default;
 $dropdown-divider-margin-y:         $spacer * .5 !default;
 $dropdown-box-shadow:               $box-shadow !default;
 
-$dropdown-link-color:               $gray-900 !default;
-$dropdown-link-hover-color:         shade-color($dropdown-link-color, 10%) !default;
-$dropdown-link-hover-bg:            $gray-200 !default;
+$dropdown-link-color:               var(--#{$prefix}body-color) !default;
+$dropdown-link-hover-color:         $dropdown-link-color !default;
+$dropdown-link-hover-bg:            var(--#{$prefix}tertiary-bg) !default;
 
 $dropdown-link-active-color:        $component-active-color !default;
 $dropdown-link-active-bg:           $component-active-bg !default;
@@ -1205,28 +1252,28 @@ $pagination-padding-x-lg:           1.5rem !default;
 $pagination-font-size:              $font-size-base !default;
 
 $pagination-color:                  var(--#{$prefix}link-color) !default;
-$pagination-bg:                     $white !default;
-$pagination-border-radius:          $border-radius !default;
-$pagination-border-width:           $border-width !default;
-$pagination-margin-start:           ($pagination-border-width * -1) !default;
-$pagination-border-color:           $gray-300 !default;
+$pagination-bg:                     var(--#{$prefix}body-bg) !default;
+$pagination-border-radius:          var(--#{$prefix}border-radius) !default;
+$pagination-border-width:           var(--#{$prefix}border-width) !default;
+$pagination-margin-start:           calc($pagination-border-width * -1) !default; // stylelint-disable-line function-disallowed-list
+$pagination-border-color:           var(--#{$prefix}border-color) !default;
 
 $pagination-focus-color:            var(--#{$prefix}link-hover-color) !default;
-$pagination-focus-bg:               $gray-200 !default;
+$pagination-focus-bg:               var(--#{$prefix}secondary-bg) !default;
 $pagination-focus-box-shadow:       $input-btn-focus-box-shadow !default;
 $pagination-focus-outline:          0 !default;
 
 $pagination-hover-color:            var(--#{$prefix}link-hover-color) !default;
-$pagination-hover-bg:               $gray-200 !default;
-$pagination-hover-border-color:     $gray-300 !default;
+$pagination-hover-bg:               var(--#{$prefix}tertiary-bg) !default;
+$pagination-hover-border-color:     var(--#{$prefix}border-color) !default; // Todo in v6: remove this?
 
 $pagination-active-color:           $component-active-color !default;
 $pagination-active-bg:              $component-active-bg !default;
-$pagination-active-border-color:    $pagination-active-bg !default;
+$pagination-active-border-color:    $component-active-bg !default;
 
-$pagination-disabled-color:         $gray-600 !default;
-$pagination-disabled-bg:            $white !default;
-$pagination-disabled-border-color:  $gray-300 !default;
+$pagination-disabled-color:         var(--#{$prefix}secondary-color) !default;
+$pagination-disabled-bg:            var(--#{$prefix}secondary-bg) !default;
+$pagination-disabled-border-color:  var(--#{$prefix}border-color) !default;
 
 $pagination-transition:              color .15s ease-in-out, background-color .15s ease-in-out, border-color .15s ease-in-out, box-shadow .15s ease-in-out !default;
 
@@ -1252,16 +1299,16 @@ $card-title-color:                  null !default;
 $card-subtitle-color:               null !default;
 $card-border-width:                 var(--#{$prefix}border-width) !default;
 $card-border-color:                 var(--#{$prefix}border-color-translucent) !default;
-$card-border-radius:                $border-radius !default;
+$card-border-radius:                var(--#{$prefix}border-radius) !default;
 $card-box-shadow:                   null !default;
 $card-inner-border-radius:          subtract($card-border-radius, $card-border-width) !default;
 $card-cap-padding-y:                $card-spacer-y * .5 !default;
 $card-cap-padding-x:                $card-spacer-x !default;
-$card-cap-bg:                       rgba($black, .03) !default;
+$card-cap-bg:                       rgba(var(--#{$prefix}body-color-rgb), .03) !default;
 $card-cap-color:                    null !default;
 $card-height:                       null !default;
 $card-color:                        null !default;
-$card-bg:                           $white !default;
+$card-bg:                           var(--#{$prefix}body-bg) !default;
 $card-img-overlay-padding:          $spacer !default;
 $card-group-margin:                 $grid-gutter-width * .5 !default;
 // scss-docs-end card-variables
@@ -1271,11 +1318,11 @@ $card-group-margin:                 $grid-gutter-width * .5 !default;
 // scss-docs-start accordion-variables
 $accordion-padding-y:                     1rem !default;
 $accordion-padding-x:                     1.25rem !default;
-$accordion-color:                         $body-color !default; // Sass variable because of $accordion-button-icon
-$accordion-bg:                            $body-bg !default;
+$accordion-color:                         var(--#{$prefix}body-color) !default; // Sass variable because of $accordion-button-icon
+$accordion-bg:                            var(--#{$prefix}body-bg) !default;
 $accordion-border-width:                  var(--#{$prefix}border-width) !default;
 $accordion-border-color:                  var(--#{$prefix}border-color) !default;
-$accordion-border-radius:                 $border-radius !default;
+$accordion-border-radius:                 var(--#{$prefix}border-radius) !default;
 $accordion-inner-border-radius:           subtract($accordion-border-radius, $accordion-border-width) !default;
 
 $accordion-body-padding-y:                $accordion-padding-y !default;
@@ -1283,18 +1330,18 @@ $accordion-body-padding-x:                $accordion-padding-x !default;
 
 $accordion-button-padding-y:              $accordion-padding-y !default;
 $accordion-button-padding-x:              $accordion-padding-x !default;
-$accordion-button-color:                  $accordion-color !default;
+$accordion-button-color:                  var(--#{$prefix}body-color) !default;
 $accordion-button-bg:                     var(--#{$prefix}accordion-bg) !default;
 $accordion-transition:                    $btn-transition, border-radius .15s ease !default;
-$accordion-button-active-bg:              tint-color($component-active-bg, 90%) !default;
-$accordion-button-active-color:           shade-color($primary, 10%) !default;
+$accordion-button-active-bg:              var(--#{$prefix}primary-bg-subtle) !default;
+$accordion-button-active-color:           var(--#{$prefix}primary-text) !default;
 
 $accordion-button-focus-border-color:     $input-focus-border-color !default;
 $accordion-button-focus-box-shadow:       $btn-focus-box-shadow !default;
 
 $accordion-icon-width:                    1.25rem !default;
-$accordion-icon-color:                    $accordion-button-color !default;
-$accordion-icon-active-color:             $accordion-button-active-color !default;
+$accordion-icon-color:                    $body-color !default;
+$accordion-icon-active-color:             $primary-text !default;
 $accordion-icon-transition:               transform .2s ease-in-out !default;
 $accordion-icon-transform:                rotate(-180deg) !default;
 
@@ -1307,9 +1354,9 @@ $accordion-button-active-icon:  url("data:image/svg+xml,<svg xmlns='http://www.w
 // scss-docs-start tooltip-variables
 $tooltip-font-size:                 $font-size-sm !default;
 $tooltip-max-width:                 200px !default;
-$tooltip-color:                     $white !default;
-$tooltip-bg:                        $black !default;
-$tooltip-border-radius:             $border-radius !default;
+$tooltip-color:                     var(--#{$prefix}body-bg) !default;
+$tooltip-bg:                        var(--#{$prefix}emphasis-color) !default;
+$tooltip-border-radius:             var(--#{$prefix}border-radius) !default;
 $tooltip-opacity:                   .9 !default;
 $tooltip-padding-y:                 $spacer * .25 !default;
 $tooltip-padding-x:                 $spacer * .5 !default;
@@ -1337,21 +1384,21 @@ $form-feedback-tooltip-border-radius: $tooltip-border-radius !default;
 
 // scss-docs-start popover-variables
 $popover-font-size:                 $font-size-sm !default;
-$popover-bg:                        $white !default;
+$popover-bg:                        var(--#{$prefix}body-bg) !default;
 $popover-max-width:                 276px !default;
 $popover-border-width:              var(--#{$prefix}border-width) !default;
 $popover-border-color:              var(--#{$prefix}border-color-translucent) !default;
-$popover-border-radius:             $border-radius-lg !default;
-$popover-inner-border-radius:       subtract($popover-border-radius, $popover-border-width) !default;
+$popover-border-radius:             var(--#{$prefix}border-radius-lg) !default;
+$popover-inner-border-radius:       calc($popover-border-radius - $popover-border-width) !default; // stylelint-disable-line function-disallowed-list
 $popover-box-shadow:                $box-shadow !default;
 
 $popover-header-font-size:          $font-size-base !default;
-$popover-header-bg:                 shade-color($popover-bg, 6%) !default;
+$popover-header-bg:                 var(--#{$prefix}secondary-bg) !default;
 $popover-header-color:              $headings-color !default;
 $popover-header-padding-y:          .5rem !default;
 $popover-header-padding-x:          $spacer !default;
 
-$popover-body-color:                $body-color !default;
+$popover-body-color:                var(--#{$prefix}body-color) !default;
 $popover-body-padding-y:            $spacer !default;
 $popover-body-padding-x:            $spacer !default;
 
@@ -1374,16 +1421,16 @@ $toast-padding-x:                   .75rem !default;
 $toast-padding-y:                   .5rem !default;
 $toast-font-size:                   .875rem !default;
 $toast-color:                       null !default;
-$toast-background-color:            rgba($white, .85) !default;
+$toast-background-color:            rgba(var(--#{$prefix}body-bg-rgb), .85) !default;
 $toast-border-width:                var(--#{$prefix}border-width) !default;
 $toast-border-color:                var(--#{$prefix}border-color-translucent) !default;
-$toast-border-radius:               $border-radius !default;
-$toast-box-shadow:                  $box-shadow !default;
+$toast-border-radius:               var(--#{$prefix}border-radius) !default;
+$toast-box-shadow:                  var(--#{$prefix}box-shadow) !default;
 $toast-spacing:                     $container-padding-x !default;
 
-$toast-header-color:                $gray-600 !default;
-$toast-header-background-color:     rgba($white, .85) !default;
-$toast-header-border-color:         rgba($black, .05) !default;
+$toast-header-color:                var(--#{$prefix}secondary-color) !default;
+$toast-header-background-color:     rgba(var(--#{$prefix}body-bg-rgb), .85) !default;
+$toast-header-border-color:         $toast-border-color !default;
 // scss-docs-end toast-variables
 
 
@@ -1412,10 +1459,10 @@ $modal-dialog-margin-y-sm-up:       1.75rem !default;
 $modal-title-line-height:           $line-height-base !default;
 
 $modal-content-color:               null !default;
-$modal-content-bg:                  $white !default;
+$modal-content-bg:                  var(--#{$prefix}body-bg) !default;
 $modal-content-border-color:        var(--#{$prefix}border-color-translucent) !default;
 $modal-content-border-width:        var(--#{$prefix}border-width) !default;
-$modal-content-border-radius:       $border-radius-lg !default;
+$modal-content-border-radius:       var(--#{$prefix}border-radius-lg) !default;
 $modal-content-inner-border-radius: subtract($modal-content-border-radius, $modal-content-border-width) !default;
 $modal-content-box-shadow-xs:       $box-shadow-sm !default;
 $modal-content-box-shadow-sm-up:    $box-shadow !default;
@@ -1462,15 +1509,20 @@ $alert-color-scale:             40% !default;
 $alert-dismissible-padding-r:   $alert-padding-x * 3 !default; // 3x covers width of x plus default padding on either side
 // scss-docs-end alert-variables
 
+// fusv-disable
+$alert-bg-scale:                -80% !default; // Deprecated in v5.2.0, to be removed in v6
+$alert-border-scale:            -70% !default; // Deprecated in v5.2.0, to be removed in v6
+$alert-color-scale:             40% !default; // Deprecated in v5.2.0, to be removed in v6
+// fusv-enable
 
 // Progress bars
 
 // scss-docs-start progress-variables
 $progress-height:                   1rem !default;
 $progress-font-size:                $font-size-base * .75 !default;
-$progress-bg:                       $gray-200 !default;
-$progress-border-radius:            $border-radius !default;
-$progress-box-shadow:               $box-shadow-inset !default;
+$progress-bg:                       var(--#{$prefix}secondary-bg) !default;
+$progress-border-radius:            var(--#{$prefix}border-radius) !default;
+$progress-box-shadow:               var(--#{$prefix}box-shadow-inset) !default;
 $progress-bar-color:                $white !default;
 $progress-bar-bg:                   $primary !default;
 $progress-bar-animation-timing:     1s linear infinite !default;
@@ -1481,30 +1533,32 @@ $progress-bar-transition:           width .6s ease !default;
 // List group
 
 // scss-docs-start list-group-variables
-$list-group-color:                  $gray-900 !default;
-$list-group-bg:                     $white !default;
-$list-group-border-color:           rgba($black, .125) !default;
-$list-group-border-width:           var(--#{$prefix}border-width) !default;
-$list-group-border-radius:          $border-radius !default;
+$list-group-color:                  var(--#{$prefix}body-color) !default;
+$list-group-bg:                     var(--#{$prefix}body-bg) !default;
+$list-group-border-color:           var(--#{$prefix}border-color) !default;
+$list-group-border-width:           $border-width !default;
+$list-group-border-radius:          var(--#{$prefix}border-radius) !default;
 
 $list-group-item-padding-y:         $spacer * .5 !default;
 $list-group-item-padding-x:         $spacer !default;
-$list-group-item-bg-scale:          -80% !default;
-$list-group-item-color-scale:       40% !default;
+// fusv-disable
+$list-group-item-bg-scale:          -80% !default; // Deprecated in v5.3.0
+$list-group-item-color-scale:       40% !default; // Deprecated in v5.3.0
+// fusv-enable
 
-$list-group-hover-bg:               $gray-100 !default;
+$list-group-hover-bg:               var(--#{$prefix}tertiary-bg) !default;
 $list-group-active-color:           $component-active-color !default;
 $list-group-active-bg:              $component-active-bg !default;
 $list-group-active-border-color:    $list-group-active-bg !default;
 
-$list-group-disabled-color:         $gray-600 !default;
+$list-group-disabled-color:         var(--#{$prefix}secondary-color) !default;
 $list-group-disabled-bg:            $list-group-bg !default;
 
-$list-group-action-color:           $gray-700 !default;
-$list-group-action-hover-color:     $list-group-action-color !default;
+$list-group-action-color:           var(--#{$prefix}secondary-color) !default;
+$list-group-action-hover-color:     var(--#{$prefix}emphasis-color) !default;
 
-$list-group-action-active-color:    $body-color !default;
-$list-group-action-active-bg:       $gray-200 !default;
+$list-group-action-active-color:    var(--#{$prefix}body-color) !default;
+$list-group-action-active-bg:       var(--#{$prefix}secondary-bg) !default;
 // scss-docs-end list-group-variables
 
 
@@ -1512,11 +1566,11 @@ $list-group-action-active-bg:       $gray-200 !default;
 
 // scss-docs-start thumbnail-variables
 $thumbnail-padding:                 .25rem !default;
-$thumbnail-bg:                      $body-bg !default;
+$thumbnail-bg:                      var(--#{$prefix}body-bg) !default;
 $thumbnail-border-width:            var(--#{$prefix}border-width) !default;
 $thumbnail-border-color:            var(--#{$prefix}border-color) !default;
-$thumbnail-border-radius:           $border-radius !default;
-$thumbnail-box-shadow:              $box-shadow-sm !default;
+$thumbnail-border-radius:           var(--#{$prefix}border-radius) !default;
+$thumbnail-box-shadow:              var(--#{$prefix}box-shadow-sm) !default;
 // scss-docs-end thumbnail-variables
 
 
@@ -1524,7 +1578,7 @@ $thumbnail-box-shadow:              $box-shadow-sm !default;
 
 // scss-docs-start figure-variables
 $figure-caption-font-size:          $small-font-size !default;
-$figure-caption-color:              $gray-600 !default;
+$figure-caption-color:              var(--#{$prefix}secondary-color) !default;
 // scss-docs-end figure-variables
 
 
@@ -1537,8 +1591,8 @@ $breadcrumb-padding-x:              0 !default;
 $breadcrumb-item-padding-x:         .5rem !default;
 $breadcrumb-margin-bottom:          1rem !default;
 $breadcrumb-bg:                     null !default;
-$breadcrumb-divider-color:          $gray-600 !default;
-$breadcrumb-active-color:           $gray-600 !default;
+$breadcrumb-divider-color:          var(--#{$prefix}secondary-color) !default;
+$breadcrumb-active-color:           var(--#{$prefix}secondary-color) !default;
 $breadcrumb-divider:                quote("/") !default;
 $breadcrumb-divider-flipped:        $breadcrumb-divider !default;
 $breadcrumb-border-radius:          null !default;
@@ -1627,8 +1681,8 @@ $offcanvas-transition-duration:     .3s !default;
 $offcanvas-border-color:            $modal-content-border-color !default;
 $offcanvas-border-width:            $modal-content-border-width !default;
 $offcanvas-title-line-height:       $modal-title-line-height !default;
-$offcanvas-bg-color:                $modal-content-bg !default;
-$offcanvas-color:                   $modal-content-color !default;
+$offcanvas-bg-color:                var(--#{$prefix}body-bg) !default;
+$offcanvas-color:                   var(--#{$prefix}body-color) !default;
 $offcanvas-box-shadow:              $modal-content-box-shadow-xs !default;
 $offcanvas-backdrop-bg:             $modal-backdrop-bg !default;
 $offcanvas-backdrop-opacity:        $modal-backdrop-opacity !default;
diff --git a/scss/bootstrap-grid.scss b/scss/bootstrap-grid.scss
index 1c4cdd1a0..4bfd4723b 100644
--- a/scss/bootstrap-grid.scss
+++ b/scss/bootstrap-grid.scss
@@ -5,10 +5,12 @@ $include-column-box-sizing: true !default;
 
 @import "functions";
 @import "variables";
+@import "variables-dark";
 @import "maps";
 
 @import "mixins/lists";
 @import "mixins/breakpoints";
+@import "mixins/color-mode";
 @import "mixins/container";
 @import "mixins/grid";
 @import "mixins/utilities";
diff --git a/scss/bootstrap-reboot.scss b/scss/bootstrap-reboot.scss
index af5274594..5b69b9552 100644
--- a/scss/bootstrap-reboot.scss
+++ b/scss/bootstrap-reboot.scss
@@ -3,6 +3,7 @@
 
 @import "functions";
 @import "variables";
+@import "variables-dark";
 @import "maps";
 @import "mixins";
 @import "root";
diff --git a/scss/bootstrap-utilities.scss b/scss/bootstrap-utilities.scss
index 2b3dbc5fe..99c4a3595 100644
--- a/scss/bootstrap-utilities.scss
+++ b/scss/bootstrap-utilities.scss
@@ -4,6 +4,7 @@
 // Configuration
 @import "functions";
 @import "variables";
+@import "variables-dark";
 @import "maps";
 @import "mixins";
 @import "utilities";
diff --git a/scss/bootstrap.scss b/scss/bootstrap.scss
index 8f8296def..449d70487 100644
--- a/scss/bootstrap.scss
+++ b/scss/bootstrap.scss
@@ -6,6 +6,7 @@
 // Configuration
 @import "functions";
 @import "variables";
+@import "variables-dark";
 @import "maps";
 @import "mixins";
 @import "utilities";
diff --git a/scss/forms/_form-check.scss b/scss/forms/_form-check.scss
index 42a2a9607..45c69a604 100644
--- a/scss/forms/_form-check.scss
+++ b/scss/forms/_form-check.scss
@@ -27,11 +27,14 @@
 }
 
 .form-check-input {
+  --#{$prefix}form-check-bg: #{escape-svg($form-check-input-bg)};
+
   width: $form-check-input-width;
   height: $form-check-input-width;
   margin-top: ($line-height-base - $form-check-input-width) * .5; // line-height minus check height
   vertical-align: top;
-  background-color: $form-check-input-bg;
+  background-color: var(--#{$prefix}form-check-bg);
+  background-image: var(--#{$prefix}form-check-bg-image);
   background-repeat: no-repeat;
   background-position: center;
   background-size: contain;
@@ -65,17 +68,17 @@
 
     &[type="checkbox"] {
       @if $enable-gradients {
-        background-image: escape-svg($form-check-input-checked-bg-image), var(--#{$prefix}gradient);
+        --#{$prefix}form-check-bg-image: #{escape-svg($form-check-input-checked-bg-image)}, var(--#{$prefix}gradient);
       } @else {
-        background-image: escape-svg($form-check-input-checked-bg-image);
+        --#{$prefix}form-check-bg-image: #{escape-svg($form-check-input-checked-bg-image)};
       }
     }
 
     &[type="radio"] {
       @if $enable-gradients {
-        background-image: escape-svg($form-check-radio-checked-bg-image), var(--#{$prefix}gradient);
+        --#{$prefix}form-check-bg-image: #{escape-svg($form-check-radio-checked-bg-image)}, var(--#{$prefix}gradient);
       } @else {
-        background-image: escape-svg($form-check-radio-checked-bg-image);
+        --#{$prefix}form-check-bg-image: #{escape-svg($form-check-radio-checked-bg-image)};
       }
     }
   }
@@ -85,9 +88,9 @@
     border-color: $form-check-input-indeterminate-border-color;
 
     @if $enable-gradients {
-      background-image: escape-svg($form-check-input-indeterminate-bg-image), var(--#{$prefix}gradient);
+      --#{$prefix}form-check-bg-image: #{escape-svg($form-check-input-indeterminate-bg-image)}, var(--#{$prefix}gradient);
     } @else {
-      background-image: escape-svg($form-check-input-indeterminate-bg-image);
+      --#{$prefix}form-check-bg-image: #{escape-svg($form-check-input-indeterminate-bg-image)};
     }
   }
 
@@ -121,24 +124,26 @@
   padding-left: $form-switch-padding-start;
 
   .form-check-input {
+    --#{$prefix}form-switch-bg: #{escape-svg($form-switch-bg-image)};
+
     width: $form-switch-width;
     margin-left: $form-switch-padding-start * -1;
-    background-image: escape-svg($form-switch-bg-image);
+    background-image: var(--#{$prefix}form-switch-bg);
     background-position: left center;
     @include border-radius($form-switch-border-radius);
     @include transition($form-switch-transition);
 
     &:focus {
-      background-image: escape-svg($form-switch-focus-bg-image);
+      --#{$prefix}form-switch-bg: #{escape-svg($form-switch-focus-bg-image)};
     }
 
     &:checked {
       background-position: $form-switch-checked-bg-position;
 
       @if $enable-gradients {
-        background-image: escape-svg($form-switch-checked-bg-image), var(--#{$prefix}gradient);
+        --#{$prefix}form-switch-bg: #{escape-svg($form-switch-checked-bg-image)}, var(--#{$prefix}gradient);
       } @else {
-        background-image: escape-svg($form-switch-checked-bg-image);
+        --#{$prefix}form-switch-bg: #{escape-svg($form-switch-checked-bg-image)};
       }
     }
   }
@@ -173,3 +178,11 @@
     }
   }
 }
+
+@if $enable-dark-mode {
+  @include color-mode(dark) {
+    .form-switch .form-check-input:not(:checked):not(:focus) {
+      --#{$prefix}form-switch-bg: #{escape-svg($form-switch-bg-image-dark)};
+    }
+  }
+}
diff --git a/scss/forms/_form-select.scss b/scss/forms/_form-select.scss
index 78c34b8fd..45b0b2686 100644
--- a/scss/forms/_form-select.scss
+++ b/scss/forms/_form-select.scss
@@ -4,6 +4,8 @@
 // https://primer.github.io/.
 
 .form-select {
+  --#{$prefix}form-select-bg-img: #{escape-svg($form-select-indicator)};
+
   display: block;
   width: 100%;
   padding: $form-select-padding-y $form-select-indicator-padding $form-select-padding-y $form-select-padding-x;
@@ -14,7 +16,7 @@
   line-height: $form-select-line-height;
   color: $form-select-color;
   background-color: $form-select-bg;
-  background-image: escape-svg($form-select-indicator);
+  background-image: var(--#{$prefix}form-select-bg-img), var(--#{$prefix}form-select-bg-icon, none);
   background-repeat: no-repeat;
   background-position: $form-select-bg-position;
   background-size: $form-select-bg-size;
@@ -69,3 +71,11 @@
   @include font-size($form-select-font-size-lg);
   @include border-radius($form-select-border-radius-lg);
 }
+
+@if $enable-dark-mode {
+  @include color-mode(dark) {
+    .form-select {
+      --#{$prefix}form-select-bg-img: #{escape-svg($form-select-indicator-dark)};
+    }
+  }
+}
diff --git a/scss/mixins/_alert.scss b/scss/mixins/_alert.scss
index 7994ed0ad..fb524af1c 100644
--- a/scss/mixins/_alert.scss
+++ b/scss/mixins/_alert.scss
@@ -1,3 +1,5 @@
+@include deprecate("`alert-variant()`", "v5.3.0", "v6.0.0");
+
 // scss-docs-start alert-variant-mixin
 @mixin alert-variant($background, $border, $color) {
   --#{$prefix}alert-color: #{$color};
diff --git a/scss/mixins/_color-mode.scss b/scss/mixins/_color-mode.scss
new file mode 100644
index 000000000..e30e96756
--- /dev/null
+++ b/scss/mixins/_color-mode.scss
@@ -0,0 +1,13 @@
+// scss-docs-start color-mode-mixin
+@mixin color-mode($mode: light, $type: $color-mode-type) {
+  @if $type == "media-query" {
+    @media (prefers-color-scheme: $mode) {
+      @content;
+    }
+  } @else {
+    [data-bs-theme="#{$mode}"] {
+      @content;
+    }
+  }
+}
+// scss-docs-end color-mode-mixin
diff --git a/scss/mixins/_forms.scss b/scss/mixins/_forms.scss
index 2a853a789..d47b1e41d 100644
--- a/scss/mixins/_forms.scss
+++ b/scss/mixins/_forms.scss
@@ -21,7 +21,8 @@
   $icon,
   $tooltip-color: color-contrast($color),
   $tooltip-bg-color: rgba($color, $form-feedback-tooltip-opacity),
-  $focus-box-shadow: 0 0 $input-btn-focus-blur $input-focus-width rgba($color, $input-btn-focus-color-opacity)
+  $focus-box-shadow: 0 0 $input-btn-focus-blur $input-focus-width rgba($color, $input-btn-focus-color-opacity),
+  $border-color: $color
 ) {
   .#{$state}-feedback {
     display: none;
@@ -56,7 +57,7 @@
 
   .form-control {
     @include form-validation-state-selector($state) {
-      border-color: $color;
+      border-color: $border-color;
 
       @if $enable-validation-icons {
         padding-right: $input-height-inner;
@@ -67,7 +68,7 @@
       }
 
       &:focus {
-        border-color: $color;
+        border-color: $border-color;
         box-shadow: $focus-box-shadow;
       }
     }
@@ -85,20 +86,20 @@
 
   .form-select {
     @include form-validation-state-selector($state) {
-      border-color: $color;
+      border-color: $border-color;
 
       @if $enable-validation-icons {
         &:not([multiple]):not([size]),
         &:not([multiple])[size="1"] {
+          --#{$prefix}form-select-bg-icon: #{escape-svg($icon)};
           padding-right: $form-select-feedback-icon-padding-end;
-          background-image: escape-svg($form-select-indicator), escape-svg($icon);
           background-position: $form-select-bg-position, $form-select-feedback-icon-position;
           background-size: $form-select-bg-size, $form-select-feedback-icon-size;
         }
       }
 
       &:focus {
-        border-color: $color;
+        border-color: $border-color;
         box-shadow: $focus-box-shadow;
       }
     }
@@ -114,7 +115,7 @@
 
   .form-check-input {
     @include form-validation-state-selector($state) {
-      border-color: $color;
+      border-color: $border-color;
 
       &:checked {
         background-color: $color;
diff --git a/scss/mixins/_list-group.scss b/scss/mixins/_list-group.scss
index e55415f2b..5a61f3c24 100644
--- a/scss/mixins/_list-group.scss
+++ b/scss/mixins/_list-group.scss
@@ -1,3 +1,6 @@
+@include deprecate("`list-group-item-variant()`", "v5.3.0", "v6.0.0");
+
+
 // List Groups
 
 // scss-docs-start list-group-mixin