First round of fixes

scss/_button-group.scss

@@ -133,10 +133,6 @@
   .btn:active + &,
   .btn.active + & {
     border-color: $primary;
-
-    &:focus {
-      border-color: $black;
-    }
   }
 
   .btn:disabled + &,

scss/_buttons.scss

@@ -53,12 +53,7 @@
   &:focus { // Boosted mod: no &:focus-visible to avoid issue in button tags
     // Boosted mod: added `&[data-focus-visible-added]`
     &[data-focus-visible-added] {
-      // Avoid using mixin so we can pass custom focus shadow properly
-      @if $enable-shadows {
-        box-shadow: var(--#{$prefix}btn-box-shadow), var(--#{$prefix}btn-focus-box-shadow);
-      } @else {
-        box-shadow: var(--#{$prefix}btn-focus-box-shadow);
-      }
+      @include focus-box();
     }
   }
 

scss/_carousel.scss

@@ -233,7 +233,7 @@
     &:focus {
       &[data-focus-visible-added] {
         @include focus-visible();
-        box-shadow: 0 0 0 $outline-offset $white;
+        @include focus-box();
         transform: none;
       }
     }

scss/_list-group.scss

@@ -53,7 +53,7 @@
   color: var(--#{$prefix}list-group-action-color);
   text-align: inherit; // For `<button>`s (anchors inherit)
 
-  // Boosted mod: no focus
+  // Boosted mod: default focus
   // Hover state
   &:hover{
     z-index: 1; // Place hover/focus items above their siblings for proper border styling

scss/_mixins.scss

@@ -38,11 +38,9 @@
 @import "mixins/box-shadow";
 @import "mixins/gradients";
 @import "mixins/transition";
+@import "mixins/focus"; // Boosted mod
 
 // Layout
 @import "mixins/clearfix";
 @import "mixins/container";
 @import "mixins/grid";
-
-// Utilities
-@import "mixins/focus" // Boosted mod

scss/_variables.scss

@@ -833,7 +833,7 @@ $input-btn-font-family:       inherit !default;
 $input-btn-font-size:         $font-size-base !default;
 $input-btn-line-height:       1.25 !default;
 
-$input-btn-focus-width:       .125rem !default;
+$input-btn-focus-width:       $outline-offset !default;
 // Boosted mod: no need for a blur variable
 $input-btn-focus-box-shadow:  null !default;
 
@@ -1142,8 +1142,12 @@ $form-range-thumb-bg:                      $white !default;
 $form-range-thumb-border:                  $border-width solid $black !default;
 $form-range-thumb-border-radius:           50% !default;
 $form-range-thumb-box-shadow:              0 .1rem .25rem rgba($black, .1) !default;
+$form-range-thumb-focus-box-shadow:        null !default;
 $form-range-thumb-focus-box-shadow-width:  $input-focus-width !default; // For focus box shadow issue in Edge
 $form-range-thumb-active-bg:               null !default;
+// fusv-disable
+$form-range-thumb-active-border:           $component-active-bg !default; // Boosted mod // Deprecated in v5.2.0
+// fusv-enable
 $form-range-thumb-disabled-bg:             $gray-500 !default;
 $form-range-thumb-transition:              background-color $transition-duration $transition-timing, border-color $transition-duration $transition-timing, box-shadow $transition-duration $transition-timing !default;
 // scss-docs-end form-range-variables
@@ -1401,6 +1405,9 @@ $pagination-border-color:           transparent !default; // Boosted mod
 $pagination-focus-box-shadow:       $input-btn-focus-box-shadow !default; // Boosted mod
 $pagination-focus-color:            var(--#{$prefix}link-color) !default;
 $pagination-focus-bg:               null !default;
+// fusv-disable
+$pagination-focus-outline:          $pagination-border-width solid $pagination-focus-color !default; // Deprecated in v5.2.0
+// fusv-enable
 // Boosted mod: no $pagination-focus-outline
 
 $pagination-hover-color:            var(--#{$prefix}link-color) !default; // Boosted mod
@@ -1857,7 +1864,7 @@ $carousel-control-color:             $black !default;
 $carousel-control-width:             $spacer * 3 !default;
 $carousel-control-opacity:           null !default;
 $carousel-control-hover-opacity:     null !default;
-$carousel-control-transition:        null !default;
+$carousel-control-transition:        null !default; // Boosted mod
 
 $carousel-indicator-width:           .5rem !default;
 $carousel-indicator-height:          .5rem !default;

scss/forms/_form-check.scss

@@ -273,6 +273,7 @@
   &[data-focus-visible-added] {
     + .btn {
       @include focus-visible();
+      @include focus-box();
     }
   }
 

scss/forms/_form-range.scss

@@ -10,11 +10,17 @@
   padding: 0; // Need to reset padding
   background-color: transparent;
   appearance: none;
-  outline: 0;
 
   &:focus {
+    outline: 0;
+
+    // Pseudo-elements must be split across multiple rulesets to have an effect.
+    // No box-shadow() mixin for focus accessibility.
+    &::-webkit-slider-thumb { box-shadow: $form-range-thumb-focus-box-shadow; }
+    &::-moz-range-thumb     { box-shadow: $form-range-thumb-focus-box-shadow; }
+
+    // Boosted mod: added `&[data-focus-visible-added]`
     &[data-focus-visible-added] {
-      outline: 0;
       // Boosted mod: better focus visibility
       &::-webkit-slider-thumb {
         @include focus-visible();
@@ -24,6 +30,7 @@
       }
       // End mod
     }
+    // End mod
   }
 
   &::-moz-focus-outer {

scss/helpers/_colored-links.scss

@@ -5,8 +5,7 @@
     background-color: color-contrast($value) !important; // Boosted mod: ensure contrast
 
     @if $link-shade-percentage != 0 {
-      &:hover,
-      &:focus {
+      &:hover {
         color: if(color-contrast($value) == $color-contrast-light, shade-color($value, $link-shade-percentage), tint-color($value, $link-shade-percentage)) !important; // stylelint-disable-line declaration-no-important
       }
     }

scss/mixins/_list-group.scss

@@ -7,8 +7,7 @@
     background-color: $background;
 
     &.list-group-item-action {
-      &:hover,
-      &:focus {
+      &:hover {
         color: $color;
         background-color: if($color == $white, shade-color($background, 10%), tint-color($background, 10%)); // Boosted mod
       }

site/assets/scss/_anchor.scss

@@ -10,7 +10,6 @@
     content: "#";
   }
 
-  &:focus,
   &:hover,
   :hover > &,
   :target > & {
@@ -21,7 +20,9 @@
 
   // Boosted mod
   &:focus {
-    outline-offset: 0;
+    &[data-focus-visible-added] {
+      @include focus-visible();
+    }
   }
   // End mod
 }