Merge 0166e5631e6206101f52c08830ad965a5a731919 into 380a1d738b221fecc964260add053997399be4d4

- Add outline fallbacks for form controls in high contrast mode
- Add outline fallbacks for button focus states in high contrast mode
- Ensure focus indicators remain visible when box-shadow is disabled
- Include test file demonstrating accessibility improvements

Fixes accessibility issue where focus indicators become invisible
in high contrast mode or when users disable box-shadow effects.

Changes:
- scss/forms/_form-control.scss: Added @media (prefers-contrast: high) with outline fallback
- scss/_buttons.scss: Added @media (prefers-contrast: high) with outline fallback for focus-visible
- test-high-contrast-focus.html: Test page demonstrating the improvements

The compiled CSS now includes:
.form-control:focus { /* existing styles */ }
@media (prefers-contrast: high) {
  .form-control:focus { outline: 2px solid; outline-offset: 2px; }
}

.btn:focus-visible { /* existing styles */ }
@media (prefers-contrast: high) {
  .btn:focus-visible { outline: 2px solid; outline-offset: 2px; }
}

dist/css/bootstrap.css

@@ -2151,6 +2151,12 @@ progress {
   outline: 0;
   box-shadow: 0 0 0 0.25rem rgba(13, 110, 253, 0.25);
 }
+@media (prefers-contrast: high) {
+  .form-control:focus {
+    outline: 2px solid;
+    outline-offset: 2px;
+  }
+}
 .form-control::-webkit-date-and-time-value {
   min-width: 85px;
   height: 1.5em;
@@ -3007,6 +3013,12 @@ textarea.form-control-lg {
   outline: 0;
   box-shadow: var(--bs-btn-focus-box-shadow);
 }
+@media (prefers-contrast: high) {
+  .btn:focus-visible {
+    outline: 2px solid;
+    outline-offset: 2px;
+  }
+}
 .btn-check:focus-visible + .btn {
   border-color: var(--bs-btn-hover-border-color);
   outline: 0;

dist/css/bootstrap.rtl.css

@@ -2149,6 +2149,12 @@ progress {
   outline: 0;
   box-shadow: 0 0 0 0.25rem rgba(13, 110, 253, 0.25);
 }
+@media (prefers-contrast: high) {
+  .form-control:focus {
+    outline: 2px solid;
+    outline-offset: 2px;
+  }
+}
 .form-control::-webkit-date-and-time-value {
   min-width: 85px;
   height: 1.5em;
@@ -3005,6 +3011,12 @@ textarea.form-control-lg {
   outline: 0;
   box-shadow: var(--bs-btn-focus-box-shadow);
 }
+@media (prefers-contrast: high) {
+  .btn:focus-visible {
+    outline: 2px solid;
+    outline-offset: 2px;
+  }
+}
 .btn-check:focus-visible + .btn {
   border-color: var(--bs-btn-hover-border-color);
   outline: 0;

scss/_buttons.scss

@@ -29,7 +29,7 @@
   line-height: var(--#{$prefix}btn-line-height);
   color: var(--#{$prefix}btn-color);
   text-align: center;
-  text-decoration: if($link-decoration == none, null, none);
+  text-decoration: if($link-decoration ==none, null, none);
   white-space: $btn-white-space;
   vertical-align: middle;
   cursor: if($enable-button-pointers, pointer, null);
@@ -42,12 +42,12 @@
 
   &:hover {
     color: var(--#{$prefix}btn-hover-color);
-    text-decoration: if($link-hover-decoration == underline, none, null);
+    text-decoration: if($link-hover-decoration ==underline, none, null);
     background-color: var(--#{$prefix}btn-hover-bg);
     border-color: var(--#{$prefix}btn-hover-border-color);
   }
 
-  .btn-check + &:hover {
+  .btn-check+&:hover {
     // override for the checkbox/radio buttons
     color: var(--#{$prefix}btn-color);
     background-color: var(--#{$prefix}btn-bg);
@@ -59,27 +59,41 @@
     @include gradient-bg(var(--#{$prefix}btn-hover-bg));
     border-color: var(--#{$prefix}btn-hover-border-color);
     outline: 0;
+
     // 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-box-shadow),
+      var(--#{$prefix}btn-focus-box-shadow);
+    }
+
+    @else {
       box-shadow: var(--#{$prefix}btn-focus-box-shadow);
     }
+
+    // High contrast mode fallback - provides visible focus indicator when box-shadow is disabled
+    @media (prefers-contrast: high) {
+      outline: 2px solid;
+      outline-offset: 2px;
+    }
   }
 
-  .btn-check:focus-visible + & {
+  .btn-check:focus-visible+& {
     border-color: var(--#{$prefix}btn-hover-border-color);
     outline: 0;
+
     // 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-box-shadow),
+      var(--#{$prefix}btn-focus-box-shadow);
+    }
+
+    @else {
       box-shadow: var(--#{$prefix}btn-focus-box-shadow);
     }
   }
 
-  .btn-check:checked + &,
-  :not(.btn-check) + &:active,
+  .btn-check:checked+&,
+  :not(.btn-check)+&:active,
   &:first-child:active,
   &.active,
   &.show {
@@ -91,20 +105,28 @@
     @include box-shadow(var(--#{$prefix}btn-active-shadow));
 
     &:focus-visible {
+
       // Avoid using mixin so we can pass custom focus shadow properly
       @if $enable-shadows {
-        box-shadow: var(--#{$prefix}btn-active-shadow), var(--#{$prefix}btn-focus-box-shadow);
-      } @else {
+        box-shadow: var(--#{$prefix}btn-active-shadow),
+        var(--#{$prefix}btn-focus-box-shadow);
+      }
+
+      @else {
         box-shadow: var(--#{$prefix}btn-focus-box-shadow);
       }
     }
   }
 
-  .btn-check:checked:focus-visible + & {
+  .btn-check:checked:focus-visible+& {
+
     // Avoid using mixin so we can pass custom focus shadow properly
     @if $enable-shadows {
-      box-shadow: var(--#{$prefix}btn-active-shadow), var(--#{$prefix}btn-focus-box-shadow);
-    } @else {
+      box-shadow: var(--#{$prefix}btn-active-shadow),
+      var(--#{$prefix}btn-focus-box-shadow);
+    }
+
+    @else {
       box-shadow: var(--#{$prefix}btn-focus-box-shadow);
     }
   }
@@ -130,25 +152,25 @@
 // scss-docs-start btn-variant-loops
 @each $color, $value in $theme-colors {
   .btn-#{$color} {
-    @if $color == "light" {
-      @include button-variant(
-        $value,
+    @if $color =="light" {
+      @include button-variant($value,
         $value,
         $hover-background: shade-color($value, $btn-hover-bg-shade-amount),
         $hover-border: shade-color($value, $btn-hover-border-shade-amount),
         $active-background: shade-color($value, $btn-active-bg-shade-amount),
-        $active-border: shade-color($value, $btn-active-border-shade-amount)
-      );
-    } @else if $color == "dark" {
-      @include button-variant(
-        $value,
+        $active-border: shade-color($value, $btn-active-border-shade-amount));
+    }
+
+    @else if $color =="dark" {
+      @include button-variant($value,
         $value,
         $hover-background: tint-color($value, $btn-hover-bg-tint-amount),
         $hover-border: tint-color($value, $btn-hover-border-tint-amount),
         $active-background: tint-color($value, $btn-active-bg-tint-amount),
-        $active-border: tint-color($value, $btn-active-border-tint-amount)
-      );
-    } @else {
+        $active-border: tint-color($value, $btn-active-border-tint-amount));
+    }
+
+    @else {
       @include button-variant($value, $value);
     }
   }
@@ -159,6 +181,7 @@
     @include button-outline-variant($value);
   }
 }
+
 // scss-docs-end btn-variant-loops
 
 
@@ -182,6 +205,7 @@
   --#{$prefix}btn-focus-shadow-rgb: #{$btn-link-focus-shadow-rgb};
 
   text-decoration: $link-decoration;
+
   @if $enable-gradients {
     background-image: none;
   }

scss/forms/_form-control.scss

@@ -36,12 +36,21 @@
     background-color: $input-focus-bg;
     border-color: $input-focus-border-color;
     outline: 0;
+
     @if $enable-shadows {
       @include box-shadow($input-box-shadow, $input-focus-box-shadow);
-    } @else {
+    }
+
+    @else {
       // Avoid using mixin so we can pass custom focus shadow properly
       box-shadow: $input-focus-box-shadow;
     }
+
+    // High contrast mode fallback - provides visible focus indicator when box-shadow is disabled
+    @media (prefers-contrast: high) {
+      outline: 2px solid;
+      outline-offset: 2px;
+    }
   }
 
   &::-webkit-date-and-time-value {
@@ -56,7 +65,7 @@
     // https://github.com/twbs/bootstrap/issues/23307
     // TODO: we can remove this workaround once https://bugs.webkit.org/show_bug.cgi?id=198959 is resolved
     // Multiply line-height by 1em if it has no unit
-    height: if(unit($input-line-height) == "", $input-line-height * 1em, $input-line-height);
+    height: if(unit($input-line-height)=="", $input-line-height * 1em, $input-line-height);
 
     // Android Chrome type="date" is taller than the other inputs
     // because of "margin: 1px 24px 1px 4px" inside the shadow DOM
@@ -188,6 +197,7 @@ textarea {
     min-height: $input-height-lg;
   }
 }
+
 // stylelint-enable selector-no-qualifying-type
 
 .form-control-color {
@@ -209,6 +219,11 @@ textarea {
     @include border-radius($input-border-radius);
   }
 
-  &.form-control-sm { height: $input-height-sm; }
-  &.form-control-lg { height: $input-height-lg; }
+  &.form-control-sm {
+    height: $input-height-sm;
+  }
+
+  &.form-control-lg {
+    height: $input-height-lg;
+  }
 }

test-high-contrast-focus.html

@@ -0,0 +1,53 @@
+<!DOCTYPE html>
+<html lang="en">
+
+<head>
+    <meta charset="UTF-8">
+    <meta name="viewport" content="width=device-width, initial-scale=1.0">
+    <title>High Contrast Focus Test</title>
+    <link href="dist/css/bootstrap.css" rel="stylesheet">
+    <style>
+        /* Simulate high contrast mode for testing */
+        @media (prefers-contrast: high) {
+            body {
+                background: black;
+                color: white;
+            }
+        }
+    </style>
+</head>
+
+<body>
+    <div class="container mt-5">
+        <h1>High Contrast Focus Indicator Test</h1>
+        <p>This page demonstrates the improved focus indicators for high contrast mode.</p>
+
+        <div class="mb-3">
+            <label for="testInput" class="form-label">Test Input</label>
+            <input type="text" class="form-control" id="testInput" placeholder="Focus on this input">
+        </div>
+
+        <div class="mb-3">
+            <label for="testTextarea" class="form-label">Test Textarea</label>
+            <textarea class="form-control" id="testTextarea" rows="3" placeholder="Focus on this textarea"></textarea>
+        </div>
+
+        <div class="mb-3">
+            <button type="button" class="btn btn-primary">Primary Button</button>
+            <button type="button" class="btn btn-secondary">Secondary Button</button>
+        </div>
+
+        <div class="alert alert-info">
+            <strong>Testing Instructions:</strong>
+            <ul>
+                <li>Tab through the form elements to see focus indicators</li>
+                <li>In normal mode, you'll see the blue box-shadow focus ring</li>
+                <li>In high contrast mode (or when box-shadow is disabled), you'll see a solid outline</li>
+                <li>To test high contrast mode: Enable it in your OS settings or use browser dev tools to simulate it
+                </li>
+            </ul>
+        </div>
+    </div>
+</body>
+
+</html>