Custom range input (#25600)

* added the styling

* added the documentation

* update for one rule per line

* fix hound error: trailing whitespace

* trimmed off vendor prefixes

* Add note about track and thumb

* Psuedo-elements must be split across multiple rulesets to have an affect

* Fix firefox inner focus

* Seems that FF is the only one affected by this

* Add support for gradients

* Add labels, clarify min/max changes

* add step example

* add custom range vars

2 files changed, 139 insertions, 0 deletions

diff --git a/scss/_custom-forms.scss b/scss/_custom-forms.scss
index 2d83f7ea68..27de8769a4 100644
--- a/scss/_custom-forms.scss
+++ b/scss/_custom-forms.scss
@@ -295,3 +295,126 @@
     @include border-radius(0 $custom-file-border-radius $custom-file-border-radius 0);
   }
 }
+
+// Range
+//
+// Style range inputs the same across browsers. Vendor-specific rules for psuedo
+// elements cannot be mixed. As such, there are no shared styles for focus or
+// active states on prefixed selectors.
+
+.custom-range {
+  width: 100%;
+  padding-left: 0; // Firefox specific
+  background-color: transparent;
+  appearance: none;
+
+  &:focus {
+    outline: none;
+  }
+
+  &::-moz-focus-outer {
+    border: 0;
+  }
+
+  &::-webkit-slider-thumb {
+    width: $custom-range-thumb-width;
+    height: $custom-range-thumb-height;
+    margin-top: -($custom-range-thumb-width * .25); // Webkit specific?
+    @include gradient-bg($custom-range-thumb-bg);
+    border: $custom-range-thumb-border;
+    @include border-radius($custom-range-thumb-border-radius);
+    @include box-shadow($custom-range-thumb-box-shadow);
+    appearance: none;
+
+    &:focus {
+      outline: none;
+      box-shadow: $custom-range-thumb-focus-box-shadow; // No mixin for focus accessibility
+    }
+
+    &:active {
+      @include gradient-bg($custom-range-thumb-active-bg);
+    }
+  }
+
+  &::-webkit-slider-runnable-track {
+    width: $custom-range-track-width;
+    height: $custom-range-track-height;
+    color: transparent; // Why?
+    cursor: $custom-range-track-cursor;
+    background-color: $custom-range-track-bg;
+    border-color: transparent;
+    @include border-radius($custom-range-track-border-radius);
+    @include box-shadow($custom-range-track-box-shadow);
+  }
+
+  &::-moz-range-thumb {
+    width: $custom-range-thumb-width;
+    height: $custom-range-thumb-height;
+    @include gradient-bg($custom-range-thumb-bg);
+    border: $custom-range-thumb-border;
+    @include border-radius($custom-range-thumb-border-radius);
+    @include box-shadow($custom-range-thumb-box-shadow);
+    appearance: none;
+
+    &:focus {
+      outline: none;
+      box-shadow: $custom-range-thumb-focus-box-shadow; // No mixin for focus accessibility
+    }
+
+    &:active {
+      @include gradient-bg($custom-range-thumb-active-bg);
+    }
+  }
+
+  &::-moz-range-track {
+    width: $custom-range-track-width;
+    height: $custom-range-track-height;
+    color: transparent;
+    cursor: $custom-range-track-cursor;
+    background-color: $custom-range-track-bg;
+    border-color: transparent; // Firefox specific?
+    @include border-radius($custom-range-track-border-radius);
+    @include box-shadow($custom-range-track-box-shadow);
+  }
+
+  &::-ms-thumb {
+    width: $custom-range-thumb-width;
+    height: $custom-range-thumb-height;
+    @include gradient-bg($custom-range-thumb-bg);
+    border: $custom-range-thumb-border;
+    @include border-radius($custom-range-thumb-border-radius);
+    @include box-shadow($custom-range-thumb-box-shadow);
+    appearance: none;
+
+    &:focus {
+      outline: none;
+      box-shadow: $custom-range-thumb-focus-box-shadow; // No mixin for focus accessibility
+    }
+
+    &:active {
+      @include gradient-bg($custom-range-thumb-active-bg);
+    }
+  }
+
+  &::-ms-track {
+    width: $custom-range-track-width;
+    height: $custom-range-track-height;
+    color: transparent;
+    cursor: $custom-range-track-cursor;
+    background-color: transparent;
+    border-color: transparent;
+    border-width: ($custom-range-thumb-height * .5);
+    @include box-shadow($custom-range-track-box-shadow);
+  }
+
+  &::-ms-fill-lower {
+    background-color: $custom-range-track-bg;
+    @include border-radius($custom-range-track-border-radius);
+  }
+
+  &::-ms-fill-upper {
+    margin-right: 15px; // arbitrary?
+    background-color: $custom-range-track-bg;
+    @include border-radius($custom-range-track-border-radius);
+  }
+}
diff --git a/scss/_variables.scss b/scss/_variables.scss
index 53cb29c2af..0a34e6c674 100644
--- a/scss/_variables.scss
+++ b/scss/_variables.scss
@@ -504,6 +504,22 @@ $custom-select-height-sm:           $input-height-sm !default;
 $custom-select-font-size-lg:        125% !default;
 $custom-select-height-lg:           $input-height-lg !default;
 
+$custom-range-track-width:          100% !default;
+$custom-range-track-height:         .5rem !default;
+$custom-range-track-cursor:         pointer !default;
+$custom-range-track-bg:             $gray-300 !default;
+$custom-range-track-border-radius:  1rem !default;
+$custom-range-track-box-shadow:     inset 0 .25rem .25rem rgba($black, .1) !default;
+
+$custom-range-thumb-width:            1rem !default;
+$custom-range-thumb-height:           $custom-range-thumb-width !default;
+$custom-range-thumb-bg:               $component-active-bg !default;
+$custom-range-thumb-border:           0 !default;
+$custom-range-thumb-border-radius:    1rem !default;
+$custom-range-thumb-box-shadow:       0 .1rem .25rem rgba($black, .1) !default;
+$custom-range-thumb-focus-box-shadow: 0 0 0 1px $body-bg, $input-btn-focus-box-shadow !default;
+$custom-range-thumb-active-bg:        lighten($component-active-bg, 35%) !default;
+
 $custom-file-height:                $input-height !default;
 $custom-file-focus-border-color:    $input-focus-border-color !default;
 $custom-file-focus-box-shadow:      $input-btn-focus-box-shadow !default;