Upgrade to Bootstrap v4.6.2

Preparation for migration to v5

Author: Rotzbua

_sass/bootstrap/_alert.scss

@@ -34,6 +34,7 @@
     position: absolute;
     top: 0;
     right: 0;
+    z-index: 2;
     padding: $alert-padding-y $alert-padding-x;
     color: inherit;
   }

_sass/bootstrap/_breadcrumb.scss

@@ -10,14 +10,12 @@
 }
 
 .breadcrumb-item {
-  display: flex;
-
   // The separator between breadcrumbs (by default, a forward-slash: "/")
   + .breadcrumb-item {
     padding-left: $breadcrumb-item-padding;
 
     &::before {
-      display: inline-block; // Suppress underlining of the separator in modern browsers
+      float: left; // Suppress inline spacings and underlining of the separator
       padding-right: $breadcrumb-item-padding;
       color: $breadcrumb-divider-color;
       content: escape-svg($breadcrumb-divider);

_sass/bootstrap/_card.scss

@@ -58,7 +58,7 @@
 }
 
 .card-subtitle {
-  margin-top: -$card-spacer-y / 2;
+  margin-top: -$card-spacer-y * .5;
   margin-bottom: 0;
 }
 
@@ -109,15 +109,15 @@
 //
 
 .card-header-tabs {
-  margin-right: -$card-spacer-x / 2;
+  margin-right: -$card-spacer-x * .5;
   margin-bottom: -$card-spacer-y;
-  margin-left: -$card-spacer-x / 2;
+  margin-left: -$card-spacer-x * .5;
   border-bottom: 0;
 }
 
 .card-header-pills {
-  margin-right: -$card-spacer-x / 2;
-  margin-left: -$card-spacer-x / 2;
+  margin-right: -$card-spacer-x * .5;
+  margin-left: -$card-spacer-x * .5;
 }
 
 // Card image
@@ -206,12 +206,12 @@
 
           .card-img-top,
           .card-header {
-            // stylelint-disable-next-line property-blacklist
+            // stylelint-disable-next-line property-disallowed-list
             border-top-right-radius: 0;
           }
           .card-img-bottom,
           .card-footer {
-            // stylelint-disable-next-line property-blacklist
+            // stylelint-disable-next-line property-disallowed-list
             border-bottom-right-radius: 0;
           }
         }
@@ -221,12 +221,12 @@
 
           .card-img-top,
           .card-header {
-            // stylelint-disable-next-line property-blacklist
+            // stylelint-disable-next-line property-disallowed-list
             border-top-left-radius: 0;
           }
           .card-img-bottom,
           .card-footer {
-            // stylelint-disable-next-line property-blacklist
+            // stylelint-disable-next-line property-disallowed-list
             border-bottom-left-radius: 0;
           }
         }

_sass/bootstrap/_carousel.scss

@@ -95,8 +95,11 @@
   align-items: center; // 2. vertically center contents
   justify-content: center; // 3. horizontally center contents
   width: $carousel-control-width;
+  padding: 0;
   color: $carousel-control-color;
   text-align: center;
+  background: none;
+  border: 0;
   opacity: $carousel-control-opacity;
   @include transition($carousel-control-transition);
 
@@ -127,7 +130,7 @@
   display: inline-block;
   width: $carousel-control-icon-width;
   height: $carousel-control-icon-width;
-  background: no-repeat 50% / 100% 100%;
+  background: 50% / 100% 100% no-repeat;
 }
 .carousel-control-prev-icon {
   background-image: escape-svg($carousel-control-prev-icon-bg);
@@ -186,9 +189,9 @@
 
 .carousel-caption {
   position: absolute;
-  right: (100% - $carousel-caption-width) / 2;
+  right: (100% - $carousel-caption-width) * .5;
   bottom: 20px;
-  left: (100% - $carousel-caption-width) / 2;
+  left: (100% - $carousel-caption-width) * .5;
   z-index: 10;
   padding-top: 20px;
   padding-bottom: 20px;

_sass/bootstrap/_custom-forms.scss

@@ -13,6 +13,7 @@
   display: block;
   min-height: $font-size-base * $line-height-base;
   padding-left: $custom-control-gutter + $custom-control-indicator-size;
+  print-color-adjust: exact; // Keep themed appearance for print
 }
 
 .custom-control-inline {
@@ -25,7 +26,7 @@
   left: 0;
   z-index: -1; // Put the input behind the label so it doesn't overlay text
   width: $custom-control-indicator-size;
-  height: ($font-size-base * $line-height-base + $custom-control-indicator-size) / 2;
+  height: ($font-size-base * $line-height-base + $custom-control-indicator-size) * .5;
   opacity: 0;
 
   &:checked ~ .custom-control-label::before {
@@ -38,7 +39,7 @@
   &:focus ~ .custom-control-label::before {
     // the mixin is not used here to make sure there is feedback
     @if $enable-shadows {
-      box-shadow: $input-box-shadow, $input-focus-box-shadow;
+      box-shadow: $input-box-shadow, $custom-control-indicator-focus-box-shadow;
     } @else {
       box-shadow: $custom-control-indicator-focus-box-shadow;
     }
@@ -82,28 +83,28 @@
   // Background-color and (when enabled) gradient
   &::before {
     position: absolute;
-    top: ($font-size-base * $line-height-base - $custom-control-indicator-size) / 2;
+    top: ($font-size-base * $line-height-base - $custom-control-indicator-size) * .5;
     left: -($custom-control-gutter + $custom-control-indicator-size);
     display: block;
     width: $custom-control-indicator-size;
     height: $custom-control-indicator-size;
     pointer-events: none;
     content: "";
     background-color: $custom-control-indicator-bg;
-    border: $custom-control-indicator-border-color solid $custom-control-indicator-border-width;
+    border: $custom-control-indicator-border-width solid $custom-control-indicator-border-color;
     @include box-shadow($custom-control-indicator-box-shadow);
   }
 
   // Foreground (icon)
   &::after {
     position: absolute;
-    top: ($font-size-base * $line-height-base - $custom-control-indicator-size) / 2;
+    top: ($font-size-base * $line-height-base - $custom-control-indicator-size) * .5;
     left: -($custom-control-gutter + $custom-control-indicator-size);
     display: block;
     width: $custom-control-indicator-size;
     height: $custom-control-indicator-size;
     content: "";
-    background: no-repeat 50% / #{$custom-control-indicator-bg-size};
+    background: 50% / #{$custom-control-indicator-bg-size} no-repeat;
   }
 }
 
@@ -150,7 +151,7 @@
 
 .custom-radio {
   .custom-control-label::before {
-    // stylelint-disable-next-line property-blacklist
+    // stylelint-disable-next-line property-disallowed-list
     border-radius: $custom-radio-indicator-border-radius;
   }
 
@@ -180,17 +181,17 @@
       left: -($custom-switch-width + $custom-control-gutter);
       width: $custom-switch-width;
       pointer-events: all;
-      // stylelint-disable-next-line property-blacklist
+      // stylelint-disable-next-line property-disallowed-list
       border-radius: $custom-switch-indicator-border-radius;
     }
 
     &::after {
-      top: add(($font-size-base * $line-height-base - $custom-control-indicator-size) / 2, $custom-control-indicator-border-width * 2);
+      top: add(($font-size-base * $line-height-base - $custom-control-indicator-size) * .5, $custom-control-indicator-border-width * 2);
       left: add(-($custom-switch-width + $custom-control-gutter), $custom-control-indicator-border-width * 2);
       width: $custom-switch-indicator-size;
       height: $custom-switch-indicator-size;
       background-color: $custom-control-indicator-border-color;
-      // stylelint-disable-next-line property-blacklist
+      // stylelint-disable-next-line property-disallowed-list
       border-radius: $custom-switch-indicator-border-radius;
       @include transition(transform .15s ease-in-out, $custom-forms-transition);
     }
@@ -314,6 +315,7 @@
   width: 100%;
   height: $custom-file-height;
   margin: 0;
+  overflow: hidden;
   opacity: 0;
 
   &:focus ~ .custom-file-label {
@@ -346,6 +348,7 @@
   z-index: 1;
   height: $custom-file-height;
   padding: $custom-file-padding-y $custom-file-padding-x;
+  overflow: hidden;
   font-family: $custom-file-font-family;
   font-weight: $custom-file-font-weight;
   line-height: $custom-file-line-height;
@@ -387,7 +390,7 @@
   appearance: none;
 
   &:focus {
-    outline: none;
+    outline: 0;
 
     // Pseudo-elements must be split across multiple rulesets to have an effect.
     // No box-shadow() mixin for focus accessibility.
@@ -403,7 +406,7 @@
   &::-webkit-slider-thumb {
     width: $custom-range-thumb-width;
     height: $custom-range-thumb-height;
-    margin-top: ($custom-range-track-height - $custom-range-thumb-height) / 2; // Webkit specific
+    margin-top: ($custom-range-track-height - $custom-range-thumb-height) * .5; // Webkit specific
     @include gradient-bg($custom-range-thumb-bg);
     border: $custom-range-thumb-border;
     @include border-radius($custom-range-thumb-border-radius);
@@ -478,7 +481,7 @@
     cursor: $custom-range-track-cursor;
     background-color: transparent;
     border-color: transparent;
-    border-width: $custom-range-thumb-height / 2;
+    border-width: $custom-range-thumb-height * .5;
     @include box-shadow($custom-range-track-box-shadow);
   }
 

_sass/bootstrap/_dropdown.scss

@@ -22,7 +22,7 @@
   display: none; // none by default, but block on "open" of the menu
   float: left;
   min-width: $dropdown-min-width;
-  padding: $dropdown-padding-y 0;
+  padding: $dropdown-padding-y $dropdown-padding-x;
   margin: $dropdown-spacer 0 0; // override default ul
   @include font-size($dropdown-font-size);
   color: $dropdown-color;
@@ -100,7 +100,7 @@
   }
 }
 
-// When enabled Popper.js, reset basic dropdown position
+// When Popper is enabled, reset the basic dropdown position
 // stylelint-disable-next-line no-duplicate-selectors
 .dropdown-menu {
   &[x-placement^="top"],

_sass/bootstrap/_forms.scss

@@ -30,12 +30,6 @@
     border: 0;
   }
 
-  // Remove select outline from select box in FF
-  &:-moz-focusring {
-    color: transparent;
-    text-shadow: 0 0 0 $input-color;
-  }
-
   // Customize the `:focus` state to imitate native WebKit styles.
   @include form-control-focus($ignore-warning: true);
 
@@ -69,6 +63,12 @@ input[type="month"] {
 }
 
 select.form-control {
+  // Remove select outline from select box in FF
+  &:-moz-focusring {
+    color: transparent;
+    text-shadow: 0 0 0 $input-color;
+  }
+
   &:focus::-ms-value {
     // Suppress the nested default white text on blue background highlight given to
     // the selected option text when the (still closed) <select> receives focus
@@ -199,13 +199,13 @@ textarea.form-control {
 .form-row {
   display: flex;
   flex-wrap: wrap;
-  margin-right: -$form-grid-gutter-width / 2;
-  margin-left: -$form-grid-gutter-width / 2;
+  margin-right: -$form-grid-gutter-width * .5;
+  margin-left: -$form-grid-gutter-width * .5;
 
   > .col,
   > [class*="col-"] {
-    padding-right: $form-grid-gutter-width / 2;
-    padding-left: $form-grid-gutter-width / 2;
+    padding-right: $form-grid-gutter-width * .5;
+    padding-left: $form-grid-gutter-width * .5;
   }
 }
 

_sass/bootstrap/_functions.scss

@@ -51,6 +51,9 @@
 }
 
 // See https://codepen.io/kevinweber/pen/dXWoRw
+//
+// Requires the use of quotes around data URIs.
+
 @function escape-svg($string) {
   @if str-index($string, "data:image/svg+xml") {
     @each $char, $encoded in $escaped-characters {
@@ -72,7 +75,7 @@
   $g: green($color);
   $b: blue($color);
 
-  $yiq: (($r * 299) + ($g * 587) + ($b * 114)) / 1000;
+  $yiq: (($r * 299) + ($g * 587) + ($b * 114)) * .001;
 
   @if ($yiq >= $yiq-contrasted-threshold) {
     @return $dark;
@@ -137,5 +140,51 @@
     @return $value1 - $value2;
   }
 
+  @if type-of($value2) != number {
+    $value2: unquote("(") + $value2 + unquote(")");
+  }
+
   @return if($return-calc == true, calc(#{$value1} - #{$value2}), $value1 + unquote(" - ") + $value2);
 }
+
+@function divide($dividend, $divisor, $precision: 10) {
+  $sign: if($dividend > 0 and $divisor > 0 or $dividend < 0 and $divisor < 0, 1, -1);
+  $dividend: abs($dividend);
+  $divisor: abs($divisor);
+  @if $dividend == 0 {
+    @return 0;
+  }
+  @if $divisor == 0 {
+    @error "Cannot divide by 0";
+  }
+  $remainder: $dividend;
+  $result: 0;
+  $factor: 10;
+  @while ($remainder > 0 and $precision >= 0) {
+    $quotient: 0;
+    @while ($remainder >= $divisor) {
+      $remainder: $remainder - $divisor;
+      $quotient: $quotient + 1;
+    }
+    $result: $result * 10 + $quotient;
+    $factor: $factor * .1;
+    $remainder: $remainder * 10;
+    $precision: $precision - 1;
+    @if ($precision < 0 and $remainder >= $divisor * 5) {
+      $result: $result + 1;
+    }
+  }
+  $result: $result * $factor * $sign;
+  $dividend-unit: unit($dividend);
+  $divisor-unit: unit($divisor);
+  $unit-map: (
+    "px": 1px,
+    "rem": 1rem,
+    "em": 1em,
+    "%": 1%
+  );
+  @if ($dividend-unit != $divisor-unit and map-has-key($unit-map, $dividend-unit)) {
+    $result: $result * map-get($unit-map, $dividend-unit);
+  }
+  @return $result;
+}

_sass/bootstrap/_images.scss

@@ -32,7 +32,7 @@
 }
 
 .figure-img {
-  margin-bottom: $spacer / 2;
+  margin-bottom: $spacer * .5;
   line-height: 1;
 }