Update form validation styles to use new CSS variables for color and border-color (#38044)

* Update form validation styles to use new CSS variables for color and border-color

* Use better Sass variables

scss/_root.scss

@@ -123,6 +123,13 @@
   // By default, there is no `--bs-focus-ring-x`, `--bs-focus-ring-y`, or `--bs-focus-ring-blur`, but we provide CSS variables with fallbacks to initial `0` values
   --#{$prefix}focus-ring-box-shadow: var(--#{$prefix}focus-ring-x, 0) var(--#{$prefix}focus-ring-y, 0) var(--#{$prefix}focus-ring-blur, 0) var(--#{$prefix}focus-ring-width) var(--#{$prefix}focus-ring-color);
   // scss-docs-end root-focus-variables
+
+  // scss-docs-start root-form-validation-variables
+  --#{$prefix}form-valid-color: #{$form-valid-color};
+  --#{$prefix}form-valid-border-color: #{$form-valid-border-color};
+  --#{$prefix}form-invalid-color: #{$form-invalid-color};
+  --#{$prefix}form-invalid-border-color: #{$form-invalid-border-color};
+  // scss-docs-end root-form-validation-variables
 }
 
 @if $enable-dark-mode {
@@ -173,6 +180,11 @@
 
     --#{$prefix}border-color: #{$border-color-dark};
     --#{$prefix}border-color-translucent: #{$border-color-translucent-dark};
+
+    --#{$prefix}form-valid-color: #{$form-valid-color-dark};
+    --#{$prefix}form-valid-border-color: #{$form-valid-border-color-dark};
+    --#{$prefix}form-invalid-color: #{$form-invalid-color-dark};
+    --#{$prefix}form-invalid-border-color: #{$form-invalid-border-color-dark};
     // scss-docs-end root-dark-mode-vars
   }
 }

scss/_variables-dark.scss

@@ -65,6 +65,13 @@ $form-select-indicator-dark:        url("data:image/svg+xml,<svg xmlns='http://w
 $form-switch-color-dark:            rgba($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;
 
+// scss-docs-start form-validation-colors-dark
+$form-valid-color-dark:             $green-300 !default;
+$form-valid-border-color-dark:      $green-300 !default;
+$form-invalid-color-dark:           $red-300 !default;
+$form-invalid-border-color-dark:    $red-300 !default;
+// scss-docs-end form-validation-colors-dark
+
 
 //
 // Accordion

scss/_variables.scss

@@ -1080,23 +1080,30 @@ $form-feedback-icon-invalid-color:  $form-feedback-invalid-color !default;
 $form-feedback-icon-invalid:        url("data:image/svg+xml,<svg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 12 12' width='12' height='12' fill='none' stroke='#{$form-feedback-icon-invalid-color}'><circle cx='6' cy='6' r='4.5'/><path stroke-linejoin='round' d='M5.8 3.6h.4L6 6.5z'/><circle cx='6' cy='8.2' r='.6' fill='#{$form-feedback-icon-invalid-color}' stroke='none'/></svg>") !default;
 // scss-docs-end form-feedback-variables
 
+// scss-docs-start form-validation-colors
+$form-valid-color:                  $form-feedback-valid-color !default;
+$form-valid-border-color:           $form-feedback-valid-color !default;
+$form-invalid-color:                $form-feedback-invalid-color !default;
+$form-invalid-border-color:         $form-feedback-invalid-color !default;
+// scss-docs-end form-validation-colors
+
 // scss-docs-start form-validation-states
 $form-validation-states: (
   "valid": (
-    "color": var(--#{$prefix}success-text),
+    "color": var(--#{$prefix}form-valid-color),
     "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),
+    "border-color": var(--#{$prefix}form-valid-border-color),
   ),
   "invalid": (
-    "color": var(--#{$prefix}danger-text),
+    "color": var(--#{$prefix}form-invalid-color),
     "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),
+    "border-color": var(--#{$prefix}form-invalid-border-color),
   )
 ) !default;
 // scss-docs-end form-validation-states

site/content/docs/5.3/forms/validation.md

@@ -351,10 +351,24 @@ If your form layout allows it, you can swap the `.{valid|invalid}-feedback` clas
 
 ## CSS
 
+### Variables
+
+{{< added-in "5.3.0" >}}
+
+As part of Bootstrap's evolving CSS variables approach, forms now use local CSS variables for validation for enhanced real-time customization. Values for the CSS variables are set via Sass, so Sass customization is still supported, too.
+
+{{< scss-docs name="root-form-validation-variables" file="scss/_root.scss" >}}
+
+These variables are also color mode adaptive, meaning they change color while in dark mode.
+
 ### Sass variables
 
 {{< scss-docs name="form-feedback-variables" file="scss/_variables.scss" >}}
 
+{{< scss-docs name="form-validation-colors" file="scss/_variables.scss" >}}
+
+{{< scss-docs name="form-validation-colors-dark" file="scss/_variables-dark.scss" >}}
+
 ### Sass mixins
 
 Two mixins are combined together, through our [loop](#loop), to generate our form validation feedback styles.