Update to Bootstrap 4.1 and rebuild

css/custom-editor-style.css

@@ -1,2 +1,2 @@
 
-/*# sourceMappingURL=data:application/json;charset=utf8;base64,eyJ2ZXJzaW9uIjozLCJmaWxlIjoiY3VzdG9tLWVkaXRvci1zdHlsZS5jc3MiLCJzb3VyY2VzIjpbImN1c3RvbS1lZGl0b3Itc3R5bGUuc2NzcyJdLCJzb3VyY2VzQ29udGVudCI6WyIvL0FkZCB5b3VyIG93biBlZGl0b3Igc3R5bGVzIGhlcmUgb3IgY29tbWVudCBvdXQgdGhlIG5leHQgbGluZSBpZiB5b3Ugd2FudCB0byBwdWxsIGluIHRoZSB3aG9sZSBCb290c3RyYXAgc3R1ZmZcbi8vQGltcG9ydCBcInRoZW1lXCI7ICJdLCJuYW1lcyI6W10sIm1hcHBpbmdzIjoiIn0= */
+/*# sourceMappingURL=data:application/json;charset=utf8;base64,eyJ2ZXJzaW9uIjozLCJzb3VyY2VzIjpbXSwibmFtZXMiOltdLCJtYXBwaW5ncyI6IiIsImZpbGUiOiJjdXN0b20tZWRpdG9yLXN0eWxlLmNzcyIsInNvdXJjZXNDb250ZW50IjpbXX0= */

js/popper.js

@@ -1,6 +1,6 @@
 /**!
  * @fileOverview Kickass library to create and place poppers near their reference elements.
- * @version 1.13.0
+ * @version 1.14.3
  * @license
  * Copyright (c) 2016 Federico Zivolo and contributors
  *
@@ -29,6 +29,7 @@
 }(this, (function () { 'use strict';
 
 var isBrowser = typeof window !== 'undefined' && typeof document !== 'undefined';
+
 var longerTimeoutBrowsers = ['Edge', 'Trident', 'Firefox'];
 var timeoutDuration = 0;
 for (var i = 0; i < longerTimeoutBrowsers.length; i += 1) {
@@ -148,13 +149,33 @@ function getScrollParent(element) {
       overflowX = _getStyleComputedProp.overflowX,
       overflowY = _getStyleComputedProp.overflowY;
 
-  if (/(auto|scroll)/.test(overflow + overflowY + overflowX)) {
+  if (/(auto|scroll|overlay)/.test(overflow + overflowY + overflowX)) {
     return element;
   }
 
   return getScrollParent(getParentNode(element));
 }
 
+var isIE11 = isBrowser && !!(window.MSInputMethodContext && document.documentMode);
+var isIE10 = isBrowser && /MSIE 10/.test(navigator.userAgent);
+
+/**
+ * Determines if the browser is Internet Explorer
+ * @method
+ * @memberof Popper.Utils
+ * @param {Number} version to check
+ * @returns {Boolean} isIE
+ */
+function isIE(version) {
+  if (version === 11) {
+    return isIE11;
+  }
+  if (version === 10) {
+    return isIE10;
+  }
+  return isIE11 || isIE10;
+}
+
 /**
  * Returns the offset parent of the given element
  * @method
@@ -163,16 +184,23 @@ function getScrollParent(element) {
  * @returns {Element} offset parent
  */
 function getOffsetParent(element) {
+  if (!element) {
+    return document.documentElement;
+  }
+
+  var noOffsetParent = isIE(10) ? document.body : null;
+
   // NOTE: 1 DOM access here
-  var offsetParent = element && element.offsetParent;
+  var offsetParent = element.offsetParent;
+  // Skip hidden elements which don't have an offsetParent
+  while (offsetParent === noOffsetParent && element.nextElementSibling) {
+    offsetParent = (element = element.nextElementSibling).offsetParent;
+  }
+
   var nodeName = offsetParent && offsetParent.nodeName;
 
   if (!nodeName || nodeName === 'BODY' || nodeName === 'HTML') {
-    if (element) {
+    return element ? element.ownerDocument.documentElement : document.documentElement;
-      return element.ownerDocument.documentElement;
-    }
-
-    return document.documentElement;
   }
 
   // .offsetParent will return the closest TD or TABLE in case
@@ -314,29 +342,14 @@ function getBordersSize(styles, axis) {
   return parseFloat(styles['border' + sideA + 'Width'], 10) + parseFloat(styles['border' + sideB + 'Width'], 10);
 }
 
-/**
- * Tells if you are running Internet Explorer 10
- * @method
- * @memberof Popper.Utils
- * @returns {Boolean} isIE10
- */
-var isIE10 = undefined;
-
-var isIE10$1 = function () {
-  if (isIE10 === undefined) {
-    isIE10 = navigator.appVersion.indexOf('MSIE 10') !== -1;
-  }
-  return isIE10;
-};
-
 function getSize(axis, body, html, computedStyle) {
-  return Math.max(body['offset' + axis], body['scroll' + axis], html['client' + axis], html['offset' + axis], html['scroll' + axis], isIE10$1() ? html['offset' + axis] + computedStyle['margin' + (axis === 'Height' ? 'Top' : 'Left')] + computedStyle['margin' + (axis === 'Height' ? 'Bottom' : 'Right')] : 0);
+  return Math.max(body['offset' + axis], body['scroll' + axis], html['client' + axis], html['offset' + axis], html['scroll' + axis], isIE(10) ? html['offset' + axis] + computedStyle['margin' + (axis === 'Height' ? 'Top' : 'Left')] + computedStyle['margin' + (axis === 'Height' ? 'Bottom' : 'Right')] : 0);
 }
 
 function getWindowSizes() {
   var body = document.body;
   var html = document.documentElement;
-  var computedStyle = isIE10$1() && getComputedStyle(html);
+  var computedStyle = isIE(10) && getComputedStyle(html);
 
   return {
     height: getSize('Height', body, html, computedStyle),
@@ -428,8 +441,8 @@ function getBoundingClientRect(element) {
   // IE10 10 FIX: Please, don't ask, the element isn't
   // considered in DOM in some circumstances...
   // This isn't reproducible in IE10 compatibility mode of IE11
-  if (isIE10$1()) {
+  try {
-    try {
+    if (isIE(10)) {
       rect = element.getBoundingClientRect();
       var scrollTop = getScroll(element, 'top');
       var scrollLeft = getScroll(element, 'left');
@@ -437,10 +450,10 @@ function getBoundingClientRect(element) {
       rect.left += scrollLeft;
       rect.bottom += scrollTop;
       rect.right += scrollLeft;
-    } catch (err) {}
+    } else {
-  } else {
+      rect = element.getBoundingClientRect();
-    rect = element.getBoundingClientRect();
+    }
-  }
+  } catch (e) {}
 
   var result = {
     left: rect.left,
@@ -472,7 +485,9 @@ function getBoundingClientRect(element) {
 }
 
 function getOffsetRectRelativeToArbitraryNode(children, parent) {
-  var isIE10 = isIE10$1();
+  var fixedPosition = arguments.length > 2 && arguments[2] !== undefined ? arguments[2] : false;
+
+  var isIE10 = isIE(10);
   var isHTML = parent.nodeName === 'HTML';
   var childrenRect = getBoundingClientRect(children);
   var parentRect = getBoundingClientRect(parent);
@@ -482,6 +497,11 @@ function getOffsetRectRelativeToArbitraryNode(children, parent) {
   var borderTopWidth = parseFloat(styles.borderTopWidth, 10);
   var borderLeftWidth = parseFloat(styles.borderLeftWidth, 10);
 
+  // In cases where the parent is fixed, we must ignore negative scroll in offset calc
+  if (fixedPosition && parent.nodeName === 'HTML') {
+    parentRect.top = Math.max(parentRect.top, 0);
+    parentRect.left = Math.max(parentRect.left, 0);
+  }
   var offsets = getClientRect({
     top: childrenRect.top - parentRect.top - borderTopWidth,
     left: childrenRect.left - parentRect.left - borderLeftWidth,
@@ -509,7 +529,7 @@ function getOffsetRectRelativeToArbitraryNode(children, parent) {
     offsets.marginLeft = marginLeft;
   }
 
-  if (isIE10 ? parent.contains(scrollParent) : parent === scrollParent && scrollParent.nodeName !== 'BODY') {
+  if (isIE10 && !fixedPosition ? parent.contains(scrollParent) : parent === scrollParent && scrollParent.nodeName !== 'BODY') {
     offsets = includeScroll(offsets, parent);
   }
 
@@ -517,13 +537,15 @@ function getOffsetRectRelativeToArbitraryNode(children, parent) {
 }
 
 function getViewportOffsetRectRelativeToArtbitraryNode(element) {
+  var excludeScroll = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : false;
+
   var html = element.ownerDocument.documentElement;
   var relativeOffset = getOffsetRectRelativeToArbitraryNode(element, html);
   var width = Math.max(html.clientWidth, window.innerWidth || 0);
   var height = Math.max(html.clientHeight, window.innerHeight || 0);
 
-  var scrollTop = getScroll(html);
+  var scrollTop = !excludeScroll ? getScroll(html) : 0;
-  var scrollLeft = getScroll(html, 'left');
+  var scrollLeft = !excludeScroll ? getScroll(html, 'left') : 0;
 
   var offset = {
     top: scrollTop - relativeOffset.top + relativeOffset.marginTop,
@@ -554,6 +576,26 @@ function isFixed(element) {
   return isFixed(getParentNode(element));
 }
 
+/**
+ * Finds the first parent of an element that has a transformed property defined
+ * @method
+ * @memberof Popper.Utils
+ * @argument {Element} element
+ * @returns {Element} first transformed parent or documentElement
+ */
+
+function getFixedPositionOffsetParent(element) {
+  // This check is needed to avoid errors in case one of the elements isn't defined for any reason
+  if (!element || !element.parentElement || isIE()) {
+    return document.documentElement;
+  }
+  var el = element.parentElement;
+  while (el && getStyleComputedProperty(el, 'transform') === 'none') {
+    el = el.parentElement;
+  }
+  return el || document.documentElement;
+}
+
 /**
  * Computed the boundaries limits and return them
  * @method
@@ -562,16 +604,20 @@ function isFixed(element) {
  * @param {HTMLElement} reference
  * @param {number} padding
  * @param {HTMLElement} boundariesElement - Element used to define the boundaries
+ * @param {Boolean} fixedPosition - Is in fixed position mode
  * @returns {Object} Coordinates of the boundaries
  */
 function getBoundaries(popper, reference, padding, boundariesElement) {
+  var fixedPosition = arguments.length > 4 && arguments[4] !== undefined ? arguments[4] : false;
+
   // NOTE: 1 DOM access here
+
   var boundaries = { top: 0, left: 0 };
-  var offsetParent = findCommonOffsetParent(popper, reference);
+  var offsetParent = fixedPosition ? getFixedPositionOffsetParent(popper) : findCommonOffsetParent(popper, reference);
 
   // Handle viewport case
   if (boundariesElement === 'viewport') {
-    boundaries = getViewportOffsetRectRelativeToArtbitraryNode(offsetParent);
+    boundaries = getViewportOffsetRectRelativeToArtbitraryNode(offsetParent, fixedPosition);
   } else {
     // Handle other cases based on DOM element used as boundaries
     var boundariesNode = void 0;
@@ -586,7 +632,7 @@ function getBoundaries(popper, reference, padding, boundariesElement) {
       boundariesNode = boundariesElement;
     }
 
-    var offsets = getOffsetRectRelativeToArbitraryNode(boundariesNode, offsetParent);
+    var offsets = getOffsetRectRelativeToArbitraryNode(boundariesNode, offsetParent, fixedPosition);
 
     // In case of HTML, we need a different computation
     if (boundariesNode.nodeName === 'HTML' && !isFixed(offsetParent)) {
@@ -687,11 +733,14 @@ function computeAutoPlacement(placement, refRect, popper, reference, boundariesE
  * @param {Object} state
  * @param {Element} popper - the popper element
  * @param {Element} reference - the reference element (the popper will be relative to this)
+ * @param {Element} fixedPosition - is in fixed position mode
  * @returns {Object} An object containing the offsets which will be applied to the popper
  */
 function getReferenceOffsets(state, popper, reference) {
-  var commonOffsetParent = findCommonOffsetParent(popper, reference);
+  var fixedPosition = arguments.length > 3 && arguments[3] !== undefined ? arguments[3] : null;
-  return getOffsetRectRelativeToArbitraryNode(reference, commonOffsetParent);
+
+  var commonOffsetParent = fixedPosition ? getFixedPositionOffsetParent(popper) : findCommonOffsetParent(popper, reference);
+  return getOffsetRectRelativeToArbitraryNode(reference, commonOffsetParent, fixedPosition);
 }
 
 /**
@@ -864,7 +913,7 @@ function update() {
   };
 
   // compute reference element offsets
-  data.offsets.reference = getReferenceOffsets(this.state, this.popper, this.reference);
+  data.offsets.reference = getReferenceOffsets(this.state, this.popper, this.reference, this.options.positionFixed);
 
   // compute auto placement, store placement inside the data object,
   // modifiers will be able to edit `placement` if needed
@@ -874,9 +923,12 @@ function update() {
   // store the computed placement inside `originalPlacement`
   data.originalPlacement = data.placement;
 
+  data.positionFixed = this.options.positionFixed;
+
   // compute the popper offsets
   data.offsets.popper = getPopperOffsets(this.popper, data.offsets.reference, data.placement);
-  data.offsets.popper.position = 'absolute';
+
+  data.offsets.popper.position = this.options.positionFixed ? 'fixed' : 'absolute';
 
   // run the modifiers
   data = runModifiers(this.modifiers, data);
@@ -916,7 +968,7 @@ function getSupportedPropertyName(property) {
   var prefixes = [false, 'ms', 'Webkit', 'Moz', 'O'];
   var upperProp = property.charAt(0).toUpperCase() + property.slice(1);
 
-  for (var i = 0; i < prefixes.length - 1; i++) {
+  for (var i = 0; i < prefixes.length; i++) {
     var prefix = prefixes[i];
     var toCheck = prefix ? '' + prefix + upperProp : property;
     if (typeof document.body.style[toCheck] !== 'undefined') {
@@ -937,9 +989,12 @@ function destroy() {
   // touch DOM only if `applyStyle` modifier is enabled
   if (isModifierEnabled(this.modifiers, 'applyStyle')) {
     this.popper.removeAttribute('x-placement');
-    this.popper.style.left = '';
     this.popper.style.position = '';
     this.popper.style.top = '';
+    this.popper.style.left = '';
+    this.popper.style.right = '';
+    this.popper.style.bottom = '';
+    this.popper.style.willChange = '';
     this.popper.style[getSupportedPropertyName('transform')] = '';
   }
 
@@ -1127,12 +1182,12 @@ function applyStyle(data) {
  * @method
  * @memberof Popper.modifiers
  * @param {HTMLElement} reference - The reference element used to position the popper
- * @param {HTMLElement} popper - The HTML element used as popper.
+ * @param {HTMLElement} popper - The HTML element used as popper
  * @param {Object} options - Popper.js options
  */
 function applyStyleOnLoad(reference, popper, options, modifierOptions, state) {
   // compute reference element offsets
-  var referenceOffsets = getReferenceOffsets(state, popper, reference);
+  var referenceOffsets = getReferenceOffsets(state, popper, reference, options.positionFixed);
 
   // compute auto placement, store placement inside the data object,
   // modifiers will be able to edit `placement` if needed
@@ -1143,7 +1198,7 @@ function applyStyleOnLoad(reference, popper, options, modifierOptions, state) {
 
   // Apply `position` to popper before anything else because
   // without the position applied we can't guarantee correct computations
-  setStyles(popper, { position: 'absolute' });
+  setStyles(popper, { position: options.positionFixed ? 'fixed' : 'absolute' });
 
   return options;
 }
@@ -1178,11 +1233,13 @@ function computeStyle(data, options) {
     position: popper.position
   };
 
-  // floor sides to avoid blurry text
+  // Avoid blurry text by using full pixel integers.
+  // For pixel-perfect positioning, top/bottom prefers rounded
+  // values, while left/right prefers floored values.
   var offsets = {
     left: Math.floor(popper.left),
-    top: Math.floor(popper.top),
+    top: Math.round(popper.top),
-    bottom: Math.floor(popper.bottom),
+    bottom: Math.round(popper.bottom),
     right: Math.floor(popper.right)
   };
 
@@ -1446,7 +1503,7 @@ function flip(data, options) {
     return data;
   }
 
-  var boundaries = getBoundaries(data.instance.popper, data.instance.reference, options.padding, options.boundariesElement);
+  var boundaries = getBoundaries(data.instance.popper, data.instance.reference, options.padding, options.boundariesElement, data.positionFixed);
 
   var placement = data.placement.split('-')[0];
   var placementOpposite = getOppositePlacement(placement);
@@ -1738,7 +1795,27 @@ function preventOverflow(data, options) {
     boundariesElement = getOffsetParent(boundariesElement);
   }
 
-  var boundaries = getBoundaries(data.instance.popper, data.instance.reference, options.padding, boundariesElement);
+  // NOTE: DOM access here
+  // resets the popper's position so that the document size can be calculated excluding
+  // the size of the popper element itself
+  var transformProp = getSupportedPropertyName('transform');
+  var popperStyles = data.instance.popper.style; // assignment to help minification
+  var top = popperStyles.top,
+      left = popperStyles.left,
+      transform = popperStyles[transformProp];
+
+  popperStyles.top = '';
+  popperStyles.left = '';
+  popperStyles[transformProp] = '';
+
+  var boundaries = getBoundaries(data.instance.popper, data.instance.reference, options.padding, boundariesElement, data.positionFixed);
+
+  // NOTE: DOM access here
+  // restores the original style properties after the offsets have been computed
+  popperStyles.top = top;
+  popperStyles.left = left;
+  popperStyles[transformProp] = transform;
+
   options.boundaries = boundaries;
 
   var order = options.priority;
@@ -2235,6 +2312,12 @@ var Defaults = {
    */
   placement: 'bottom',
 
+  /**
+   * Set this to true if you want popper to position it self in 'fixed' mode
+   * @prop {Boolean} positionFixed=false
+   */
+  positionFixed: false,
+
   /**
    * Whether events (resize, scroll) are initially enabled
    * @prop {Boolean} eventsEnabled=true

package.json

@@ -27,7 +27,7 @@
   },
   "homepage": "https://understrap.com",
   "dependencies": {
-    "bootstrap": "4.0.0",
+    "bootstrap": "4.1.0",
     "browser-sync": "^2.23.6",
     "del": "^3.0.0",
     "font-awesome": "^4.7.0",

sass/assets/bootstrap4.scss

@@ -1,5 +1,5 @@
 /*!
- * Bootstrap v4.0.0 (https://getbootstrap.com)
+ * Bootstrap v4.1.0 (https://getbootstrap.com/)
  * Copyright 2011-2018 The Bootstrap Authors
  * Copyright 2011-2018 Twitter, Inc.
  * Licensed under MIT (https://github.com/twbs/bootstrap/blob/master/LICENSE)

src/sass/bootstrap4/_breadcrumb.scss

@@ -5,17 +5,20 @@
   margin-bottom: $breadcrumb-margin-bottom;
   list-style: none;
   background-color: $breadcrumb-bg;
-  @include border-radius($border-radius);
+  @include border-radius($breadcrumb-border-radius);
 }
 
 .breadcrumb-item {
   // The separator between breadcrumbs (by default, a forward-slash: "/")
-  + .breadcrumb-item::before {
+  + .breadcrumb-item {
-    display: inline-block; // Suppress underlining of the separator in modern browsers
-    padding-right: $breadcrumb-item-padding;
     padding-left: $breadcrumb-item-padding;
-    color: $breadcrumb-divider-color;
+
-    content: "#{$breadcrumb-divider}";
+    &::before {
+      display: inline-block; // Suppress underlining of the separator in modern browsers
+      padding-right: $breadcrumb-item-padding;
+      color: $breadcrumb-divider-color;
+      content: $breadcrumb-divider;
+    }
   }
 
   // IE9-11 hack to properly handle hyperlink underlines for breadcrumbs built

src/sass/bootstrap4/_button-group.scss

@@ -76,9 +76,15 @@
   padding-right: $btn-padding-x * .75;
   padding-left: $btn-padding-x * .75;
 
-  &::after {
+  &::after,
+  .dropup &::after,
+  .dropright &::after {
     margin-left: 0;
   }
+
+  .dropleft &::before {
+    margin-right: 0;
+  }
 }
 
 .btn-sm + .dropdown-toggle-split {

src/sass/bootstrap4/_buttons.scss

@@ -100,6 +100,7 @@ fieldset:disabled a.btn {
   &:disabled,
   &.disabled {
     color: $btn-link-disabled-color;
+    pointer-events: none;
   }
 
   // No need for an active state here

src/sass/bootstrap4/_card.scss

@@ -153,7 +153,7 @@
 
     .card {
       display: flex;
-      // Flexbugs #4: https://github.com/philipwalton/flexbugs#4-flex-shorthand-declarations-with-unitless-flex-basis-values-are-ignored
+      // Flexbugs #4: https://github.com/philipwalton/flexbugs#flexbug-4
       flex: 1 0 0%;
       flex-direction: column;
       margin-right: $card-deck-margin;
@@ -183,7 +183,7 @@
     // The child selector allows nested `.card` within `.card-group`
     // to display properly.
     > .card {
-      // Flexbugs #4: https://github.com/philipwalton/flexbugs#4-flex-shorthand-declarations-with-unitless-flex-basis-values-are-ignored
+      // Flexbugs #4: https://github.com/philipwalton/flexbugs#flexbug-4
       flex: 1 0 0%;
       margin-bottom: 0;
 
@@ -261,6 +261,8 @@
   @include media-breakpoint-up(sm) {
     column-count: $card-columns-count;
     column-gap: $card-columns-gap;
+    orphans: 1;
+    widows: 1;
 
     .card {
       display: inline-block; // Don't let them vertically span multiple columns
@@ -268,3 +270,32 @@
     }
   }
 }
+
+
+//
+// Accordion
+//
+
+.accordion {
+  .card:not(:first-of-type):not(:last-of-type) {
+    border-bottom: 0;
+    border-radius: 0;
+  }
+
+  .card:not(:first-of-type) {
+    .card-header:first-child {
+      border-radius: 0;
+    }
+  }
+
+  .card:first-of-type {
+    border-bottom: 0;
+    border-bottom-right-radius: 0;
+    border-bottom-left-radius: 0;
+  }
+
+  .card:last-of-type {
+    border-top-left-radius: 0;
+    border-top-right-radius: 0;
+  }
+}

src/sass/bootstrap4/_carousel.scss

@@ -1,4 +1,13 @@
-// Wrapper for the slide container and indicators
+// Notes on the classes:
+//
+// 1. The .carousel-item-left and .carousel-item-right is used to indicate where
+//    the active slide is heading.
+// 2. .active.carousel-item is the current slide.
+// 3. .active.carousel-item-left and .active.carousel-item-right is the current
+//    slide in its in-transition state. Only one of these occurs at a time.
+// 4. .carousel-item-next.carousel-item-left and .carousel-item-prev.carousel-item-right
+//    is the upcoming slide in transition.
+
 .carousel {
   position: relative;
 }
@@ -31,7 +40,6 @@
   top: 0;
 }
 
-// CSS3 transforms when supported by the browser
 .carousel-item-next.carousel-item-left,
 .carousel-item-prev.carousel-item-right {
   transform: translateX(0);
@@ -60,6 +68,42 @@
 }
 
 
+//
+// Alternate transitions
+//
+
+.carousel-fade {
+  .carousel-item {
+    opacity: 0;
+    transition-duration: .6s;
+    transition-property: opacity;
+  }
+
+  .carousel-item.active,
+  .carousel-item-next.carousel-item-left,
+  .carousel-item-prev.carousel-item-right {
+    opacity: 1;
+  }
+
+  .active.carousel-item-left,
+  .active.carousel-item-right {
+    opacity: 0;
+  }
+
+  .carousel-item-next,
+  .carousel-item-prev,
+  .carousel-item.active,
+  .active.carousel-item-left,
+  .active.carousel-item-prev {
+    transform: translateX(0);
+
+    @supports (transform-style: preserve-3d) {
+      transform: translate3d(0, 0, 0);
+    }
+  }
+}
+
+
 //
 // Left/right controls for nav
 //
@@ -91,13 +135,13 @@
 .carousel-control-prev {
   left: 0;
   @if $enable-gradients {
-    background: linear-gradient(90deg, rgba(0, 0, 0, .25), rgba(0, 0, 0, .001));
+    background: linear-gradient(90deg, rgba($black, .25), rgba($black, .001));
   }
 }
 .carousel-control-next {
   right: 0;
   @if $enable-gradients {
-    background: linear-gradient(270deg, rgba(0, 0, 0, .25), rgba(0, 0, 0, .001));
+    background: linear-gradient(270deg, rgba($black, .25), rgba($black, .001));
   }
 }
 

src/sass/bootstrap4/_custom-forms.scss

@@ -157,7 +157,7 @@
 // Select
 //
 // Replaces the browser default select with a custom one, mostly pulled from
-// http://primercss.io.
+// https://primer.github.io/.
 //
 
 .custom-select {
@@ -247,11 +247,11 @@
   margin: 0;
   opacity: 0;
 
-  &:focus ~ .custom-file-control {
+  &:focus ~ .custom-file-label {
     border-color: $custom-file-focus-border-color;
     box-shadow: $custom-file-focus-box-shadow;
 
-    &::before {
+    &::after {
       border-color: $custom-file-focus-border-color;
     }
   }
@@ -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);
+  }
+}

src/sass/bootstrap4/_dropdown.scss

@@ -1,6 +1,8 @@
 // The dropdown wrapper (`<div>`)
 .dropup,
-.dropdown {
+.dropright,
+.dropdown,
+.dropleft {
   position: relative;
 }
 
@@ -31,10 +33,17 @@
   @include box-shadow($dropdown-box-shadow);
 }
 
+.dropdown-menu-right {
+  right: 0;
+  left: auto;
+}
+
 // Allow for dropdowns to go bottom up (aka, dropup-menu)
 // Just add .dropup after the standard .dropdown class and you're set.
 .dropup {
   .dropdown-menu {
+    top: auto;
+    bottom: 100%;
     margin-top: 0;
     margin-bottom: $dropdown-spacer;
   }
@@ -46,6 +55,9 @@
 
 .dropright {
   .dropdown-menu {
+    top: 0;
+    right: auto;
+    left: 100%;
     margin-top: 0;
     margin-left: $dropdown-spacer;
   }
@@ -60,6 +72,9 @@
 
 .dropleft {
   .dropdown-menu {
+    top: 0;
+    right: 100%;
+    left: auto;
     margin-top: 0;
     margin-right: $dropdown-spacer;
   }
@@ -72,6 +87,19 @@
   }
 }
 
+// When enabled Popper.js, reset basic dropdown position
+// stylelint-disable no-duplicate-selectors
+.dropdown-menu {
+  &[x-placement^="top"],
+  &[x-placement^="right"],
+  &[x-placement^="bottom"],
+  &[x-placement^="left"] {
+    right: auto;
+    bottom: auto;
+  }
+}
+// stylelint-enable no-duplicate-selectors
+
 // Dividers (basically an `<hr>`) within the dropdown
 .dropdown-divider {
   @include nav-divider($dropdown-divider-bg);
@@ -129,3 +157,10 @@
   color: $dropdown-header-color;
   white-space: nowrap; // as with > li > a
 }
+
+// Dropdown text
+.dropdown-item-text {
+  display: block;
+  padding: $dropdown-item-padding-y $dropdown-item-padding-x;
+  color: $dropdown-link-color;
+}

src/sass/bootstrap4/_forms.scss

@@ -121,6 +121,7 @@ select.form-control {
   padding-bottom: $input-padding-y;
   margin-bottom: 0; // match inputs if this class comes on inputs with default margins
   line-height: $input-line-height;
+  color: $input-plaintext-color;
   background-color: transparent;
   border: solid transparent;
   border-width: $input-border-width 0;
@@ -302,7 +303,8 @@ select.form-control-lg {
       display: inline-block;
     }
 
-    .input-group {
+    .input-group,
+    .custom-select {
       width: auto;
     }
 

src/sass/bootstrap4/_functions.scss

@@ -79,7 +79,7 @@
 // Request a theme color level
 @function theme-color-level($color-name: "primary", $level: 0) {
   $color: theme-color($color-name);
-  $color-base: if($level > 0, #000, #fff);
+  $color-base: if($level > 0, $black, $white);
   $level: abs($level);
 
   @return mix($color-base, $color, $level * $theme-color-interval);

src/sass/bootstrap4/_input-group.scss

@@ -46,9 +46,9 @@
     align-items: center;
 
     &:not(:last-child) .custom-file-label,
-    &:not(:last-child) .custom-file-label::before { @include border-right-radius(0); }
+    &:not(:last-child) .custom-file-label::after { @include border-right-radius(0); }
     &:not(:first-child) .custom-file-label,
-    &:not(:first-child) .custom-file-label::before { @include border-left-radius(0); }
+    &:not(:first-child) .custom-file-label::after { @include border-left-radius(0); }
   }
 }
 

src/sass/bootstrap4/_mixins.scss

@@ -36,7 +36,6 @@
 
 // // Layout
 @import "mixins/clearfix";
-// @import "mixins/navbar-align";
 @import "mixins/grid-framework";
 @import "mixins/grid";
 @import "mixins/float";

src/sass/bootstrap4/_modal.scss

@@ -67,7 +67,7 @@
   background-color: $modal-content-bg;
   background-clip: padding-box;
   border: $modal-content-border-width solid $modal-content-border-color;
-  @include border-radius($border-radius-lg);
+  @include border-radius($modal-content-border-radius);
   @include box-shadow($modal-content-box-shadow-xs);
   // Remove focus outline from opened modal
   outline: 0;
@@ -96,7 +96,7 @@
   justify-content: space-between; // Put modal header elements (title and dismiss) on opposite ends
   padding: $modal-header-padding;
   border-bottom: $modal-header-border-width solid $modal-header-border-color;
-  @include border-top-radius($border-radius-lg);
+  @include border-top-radius($modal-content-border-radius);
 
   .close {
     padding: $modal-header-padding;

src/sass/bootstrap4/_navbar.scss

@@ -162,11 +162,6 @@
             position: absolute;
           }
 
-          .dropdown-menu-right {
-            right: 0;
-            left: auto; // Reset the default from `.dropdown-menu`
-          }
-
           .nav-link {
             padding-right: $navbar-nav-link-padding-x;
             padding-left: $navbar-nav-link-padding-x;
@@ -189,13 +184,6 @@
         .navbar-toggler {
           display: none;
         }
-
-        .dropup {
-          .dropdown-menu {
-            top: auto;
-            bottom: 100%;
-          }
-        }
       }
     }
   }

src/sass/bootstrap4/_pagination.scss

@@ -15,6 +15,7 @@
   border: $pagination-border-width solid $pagination-border-color;
 
   &:hover {
+    z-index: 2;
     color: $pagination-hover-color;
     text-decoration: none;
     background-color: $pagination-hover-bg;
@@ -23,7 +24,7 @@
 
   &:focus {
     z-index: 2;
-    outline: 0;
+    outline: $pagination-focus-outline;
     box-shadow: $pagination-focus-box-shadow;
   }
 

src/sass/bootstrap4/_print.scss

@@ -5,7 +5,7 @@
 // ==========================================================================
 // Print styles.
 // Inlined to avoid the additional HTTP request:
-// http://www.phpied.com/delay-loading-your-print-css/
+// https://www.phpied.com/delay-loading-your-print-css/
 // ==========================================================================
 
 @if $enable-print-styles {
@@ -14,7 +14,7 @@
     *::before,
     *::after {
       // Bootstrap specific; comment out `color` and `background`
-      //color: #000 !important; // Black prints faster: http://www.sanbeiji.com/archives/953
+      //color: $black !important; // Black prints faster
       text-shadow: none !important;
       //background: transparent !important;
       box-shadow: none !important;
@@ -51,7 +51,7 @@
     }
     pre,
     blockquote {
-      border: $border-width solid #999;   // Bootstrap custom code; using `$border-width` instead of 1px
+      border: $border-width solid $gray-500;   // Bootstrap custom code; using `$border-width` instead of 1px
       page-break-inside: avoid;
     }
 
@@ -101,7 +101,7 @@
       display: none;
     }
     .badge {
-      border: $border-width solid #000;
+      border: $border-width solid $black;
     }
 
     .table {
@@ -109,13 +109,13 @@
 
       td,
       th {
-        background-color: #fff !important;
+        background-color: $white !important;
       }
     }
     .table-bordered {
       th,
       td {
-        border: 1px solid #ddd !important;
+        border: 1px solid $gray-300 !important;
       }
     }
 

src/sass/bootstrap4/_progress.scss

@@ -19,6 +19,7 @@
   justify-content: center;
   color: $progress-bar-color;
   text-align: center;
+  white-space: nowrap;
   background-color: $progress-bar-bg;
   @include transition($progress-bar-transition);
 }

src/sass/bootstrap4/_reboot.scss

@@ -30,7 +30,7 @@ html {
   -webkit-text-size-adjust: 100%; // 4
   -ms-text-size-adjust: 100%; // 4
   -ms-overflow-style: scrollbar; // 5
-  -webkit-tap-highlight-color: rgba(0, 0, 0, 0); // 6
+  -webkit-tap-highlight-color: rgba($black, 0); // 6
 }
 
 // IE10+ doesn't honor `<meta name="viewport">` in some cases.
@@ -290,7 +290,7 @@ table {
 caption {
   padding-top: $table-cell-padding;
   padding-bottom: $table-cell-padding;
-  color: $text-muted;
+  color: $table-caption-color;
   text-align: left;
   caption-side: bottom;
 }
@@ -309,7 +309,7 @@ th {
 label {
   // Allow labels to use `margin` for spacing.
   display: inline-block;
-  margin-bottom: .5rem;
+  margin-bottom: $label-margin-bottom;
 }
 
 // Remove the default `border-radius` that macOS Chrome adds.

src/sass/bootstrap4/_tables.scss

@@ -42,9 +42,9 @@
 }
 
 
-// Bordered version
+// Border versions
 //
-// Add borders all around the table and between all the columns.
+// Add or remove borders all around the table and between all the columns.
 
 .table-bordered {
   border: $table-border-width solid $table-border-color;
@@ -62,13 +62,21 @@
   }
 }
 
+.table-borderless {
+  th,
+  td,
+  thead th,
+  tbody + tbody {
+    border: 0;
+  }
+}
 
 // Zebra-striping
 //
 // Default zebra-stripe styles (alternating gray and transparent backgrounds)
 
 .table-striped {
-  tbody tr:nth-of-type(odd) {
+  tbody tr:nth-of-type(#{$table-striped-order}) {
     background-color: $table-accent-bg;
   }
 }

src/sass/bootstrap4/_transitions.scss

@@ -1,30 +1,16 @@
 // stylelint-disable selector-no-qualifying-type
 
 .fade {
-  opacity: 0;
   @include transition($transition-fade);
 
-  &.show {
+  &:not(.show) {
-    opacity: 1;
+    opacity: 0;
   }
 }
 
 .collapse {
-  display: none;
+  &:not(.show) {
-  &.show {
+    display: none;
-    display: block;
-  }
-}
-
-tr {
-  &.collapse.show {
-    display: table-row;
-  }
-}
-
-tbody {
-  &.collapse.show {
-    display: table-row-group;
   }
 }
 

src/sass/bootstrap4/_utilities.scss

@@ -8,6 +8,7 @@
 @import "utilities/float";
 @import "utilities/position";
 @import "utilities/screenreaders";
+@import "utilities/shadows";
 @import "utilities/sizing";
 @import "utilities/spacing";
 @import "utilities/text";

src/sass/bootstrap4/_variables.scss

@@ -88,11 +88,11 @@ $theme-colors: map-merge((
 $theme-color-interval:      8% !default;
 
 // The yiq lightness value that determines when the lightness of color changes from "dark" to "light". Acceptable values are between 0 and 255.
-$yiq-contrasted-threshold: 150 !default;
+$yiq-contrasted-threshold:  150 !default;
 
 // Customize the light and dark text colors for use in our YIQ color contrast function.
-$yiq-text-dark: $gray-900 !default;
+$yiq-text-dark:             $gray-900 !default;
-$yiq-text-light: $white !default;
+$yiq-text-light:            $white !default;
 
 // Options
 //
@@ -132,7 +132,8 @@ $sizes: map-merge((
   25: 25%,
   50: 50%,
   75: 75%,
-  100: 100%
+  100: 100%,
+  auto: auto
 ), $sizes);
 // stylelint-enable
 
@@ -211,6 +212,10 @@ $border-radius:               .25rem !default;
 $border-radius-lg:            .3rem !default;
 $border-radius-sm:            .2rem !default;
 
+$box-shadow-sm:               0 .125rem .25rem rgba($black, .075) !default;
+$box-shadow:                  0 .5rem 1rem rgba($black, .15) !default;
+$box-shadow-lg:               0 1rem 3rem rgba($black, .175) !default;
+
 $component-active-color:      $white !default;
 $component-active-bg:         theme-color("primary") !default;
 
@@ -317,6 +322,9 @@ $table-dark-hover-bg:         rgba($white, .075) !default;
 $table-dark-border-color:     lighten($gray-900, 7.5%) !default;
 $table-dark-color:            $body-bg !default;
 
+$table-striped-order:         odd !default;
+
+$table-caption-color:         $text-muted !default;
 
 // Buttons + Forms
 //
@@ -380,6 +388,8 @@ $btn-transition:              color .15s ease-in-out, background-color .15s ease
 
 // Forms
 
+$label-margin-bottom:                   .5rem !default;
+
 $input-padding-y:                       $input-btn-padding-y !default;
 $input-padding-x:                       $input-btn-padding-x !default;
 $input-line-height:                     $input-btn-line-height !default;
@@ -411,6 +421,7 @@ $input-focus-width:                     $input-btn-focus-width !default;
 $input-focus-box-shadow:                $input-btn-focus-box-shadow !default;
 
 $input-placeholder-color:               $gray-600 !default;
+$input-plaintext-color:                 $body-color !default;
 
 $input-height-border:                   $input-border-width * 2 !default;
 
@@ -449,7 +460,7 @@ $custom-control-indicator-bg-size:      50% 50% !default;
 $custom-control-indicator-box-shadow:   inset 0 .25rem .25rem rgba($black, .1) !default;
 
 $custom-control-indicator-disabled-bg:          $gray-200 !default;
-$custom-control-label-disabled-color:     $gray-600 !default;
+$custom-control-label-disabled-color:           $gray-600 !default;
 
 $custom-control-indicator-checked-color:        $component-active-color !default;
 $custom-control-indicator-checked-bg:           $component-active-bg !default;
@@ -465,22 +476,22 @@ $custom-control-indicator-active-box-shadow:    none !default;
 $custom-checkbox-indicator-border-radius:       $border-radius !default;
 $custom-checkbox-indicator-icon-checked:        str-replace(url("data:image/svg+xml;charset=utf8,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 8 8'%3E%3Cpath fill='#{$custom-control-indicator-checked-color}' d='M6.564.75l-3.59 3.612-1.538-1.55L0 4.26 2.974 7.25 8 2.193z'/%3E%3C/svg%3E"), "#", "%23") !default;
 
-$custom-checkbox-indicator-indeterminate-bg:    $component-active-bg !default;
+$custom-checkbox-indicator-indeterminate-bg:          $component-active-bg !default;
-$custom-checkbox-indicator-indeterminate-color: $custom-control-indicator-checked-color !default;
+$custom-checkbox-indicator-indeterminate-color:       $custom-control-indicator-checked-color !default;
-$custom-checkbox-indicator-icon-indeterminate:  str-replace(url("data:image/svg+xml;charset=utf8,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 4 4'%3E%3Cpath stroke='#{$custom-checkbox-indicator-indeterminate-color}' d='M0 2h4'/%3E%3C/svg%3E"), "#", "%23") !default;
+$custom-checkbox-indicator-icon-indeterminate:        str-replace(url("data:image/svg+xml;charset=utf8,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 4 4'%3E%3Cpath stroke='#{$custom-checkbox-indicator-indeterminate-color}' d='M0 2h4'/%3E%3C/svg%3E"), "#", "%23") !default;
-$custom-checkbox-indicator-indeterminate-box-shadow: none !default;
+$custom-checkbox-indicator-indeterminate-box-shadow:  none !default;
 
 $custom-radio-indicator-border-radius:          50% !default;
 $custom-radio-indicator-icon-checked:           str-replace(url("data:image/svg+xml;charset=utf8,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='-4 -4 8 8'%3E%3Ccircle r='3' fill='#{$custom-control-indicator-checked-color}'/%3E%3C/svg%3E"), "#", "%23") !default;
 
 $custom-select-padding-y:           .375rem !default;
-$custom-select-padding-x:          .75rem !default;
+$custom-select-padding-x:           .75rem !default;
 $custom-select-height:              $input-height !default;
 $custom-select-indicator-padding:   1rem !default; // Extra padding to account for the presence of the background-image based indicator
 $custom-select-line-height:         $input-btn-line-height !default;
 $custom-select-color:               $input-color !default;
 $custom-select-disabled-color:      $gray-600 !default;
-$custom-select-bg:                  $white !default;
+$custom-select-bg:                  $input-bg !default;
 $custom-select-disabled-bg:         $gray-200 !default;
 $custom-select-bg-size:             8px 10px !default; // In pixels because image dimensions
 $custom-select-indicator-color:     $gray-800 !default;
@@ -498,6 +509,22 @@ $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;
@@ -585,6 +612,9 @@ $nav-pills-border-radius:           $border-radius !default;
 $nav-pills-link-active-color:       $component-active-color !default;
 $nav-pills-link-active-bg:          $component-active-bg !default;
 
+$nav-divider-color:                 $gray-200 !default;
+$nav-divider-margin-y:              ($spacer / 2) !default;
+
 // Navbar
 
 $navbar-padding-y:                  ($spacer / 2) !default;
@@ -633,6 +663,7 @@ $pagination-border-width:           $border-width !default;
 $pagination-border-color:           $gray-300 !default;
 
 $pagination-focus-box-shadow:       $input-btn-focus-box-shadow !default;
+$pagination-focus-outline:          0 !default;
 
 $pagination-hover-color:            $link-hover-color !default;
 $pagination-hover-bg:               $gray-200 !default;
@@ -676,19 +707,19 @@ $card-columns-margin:               $card-spacer-y !default;
 
 // Tooltips
 
-$tooltip-font-size:           $font-size-sm !default;
+$tooltip-font-size:                 $font-size-sm !default;
-$tooltip-max-width:           200px !default;
+$tooltip-max-width:                 200px !default;
-$tooltip-color:               $white !default;
+$tooltip-color:                     $white !default;
-$tooltip-bg:                  $black !default;
+$tooltip-bg:                        $black !default;
-$tooltip-border-radius:        $border-radius !default;
+$tooltip-border-radius:             $border-radius !default;
-$tooltip-opacity:             .9 !default;
+$tooltip-opacity:                   .9 !default;
-$tooltip-padding-y:           .25rem !default;
+$tooltip-padding-y:                 .25rem !default;
-$tooltip-padding-x:           .5rem !default;
+$tooltip-padding-x:                 .5rem !default;
-$tooltip-margin:              0 !default;
+$tooltip-margin:                    0 !default;
 
-$tooltip-arrow-width:         .8rem !default;
+$tooltip-arrow-width:               .8rem !default;
-$tooltip-arrow-height:        .4rem !default;
+$tooltip-arrow-height:              .4rem !default;
-$tooltip-arrow-color:         $tooltip-bg !default;
+$tooltip-arrow-color:               $tooltip-bg !default;
 
 
 // Popovers
@@ -734,26 +765,27 @@ $badge-pill-border-radius:          10rem !default;
 // Modals
 
 // Padding applied to the modal body
-$modal-inner-padding:         1rem !default;
+$modal-inner-padding:               1rem !default;
 
-$modal-dialog-margin:         .5rem !default;
+$modal-dialog-margin:               .5rem !default;
-$modal-dialog-margin-y-sm-up: 1.75rem !default;
+$modal-dialog-margin-y-sm-up:       1.75rem !default;
 
 $modal-title-line-height:           $line-height-base !default;
 
-$modal-content-bg:               $white !default;
+$modal-content-bg:                  $white !default;
-$modal-content-border-color:     rgba($black, .2) !default;
+$modal-content-border-color:        rgba($black, .2) !default;
-$modal-content-border-width:     $border-width !default;
+$modal-content-border-width:        $border-width !default;
-$modal-content-box-shadow-xs:    0 .25rem .5rem rgba($black, .5) !default;
+$modal-content-border-radius:       $border-radius-lg !default;
-$modal-content-box-shadow-sm-up: 0 .5rem 1rem rgba($black, .5) !default;
+$modal-content-box-shadow-xs:       0 .25rem .5rem rgba($black, .5) !default;
+$modal-content-box-shadow-sm-up:    0 .5rem 1rem rgba($black, .5) !default;
 
-$modal-backdrop-bg:           $black !default;
+$modal-backdrop-bg:                 $black !default;
-$modal-backdrop-opacity:      .5 !default;
+$modal-backdrop-opacity:            .5 !default;
-$modal-header-border-color:   $gray-200 !default;
+$modal-header-border-color:         $gray-200 !default;
-$modal-footer-border-color:   $modal-header-border-color !default;
+$modal-footer-border-color:         $modal-header-border-color !default;
-$modal-header-border-width:   $modal-content-border-width !default;
+$modal-header-border-width:         $modal-content-border-width !default;
-$modal-footer-border-width:   $modal-header-border-width !default;
+$modal-footer-border-width:         $modal-header-border-width !default;
-$modal-header-padding:        1rem !default;
+$modal-header-padding:              1rem !default;
 
 $modal-lg:                          800px !default;
 $modal-md:                          500px !default;
@@ -842,7 +874,9 @@ $breadcrumb-margin-bottom:          1rem !default;
 $breadcrumb-bg:                     $gray-200 !default;
 $breadcrumb-divider-color:          $gray-600 !default;
 $breadcrumb-active-color:           $gray-600 !default;
-$breadcrumb-divider:                "/" !default;
+$breadcrumb-divider:                quote("/") !default;
+
+$breadcrumb-border-radius:          $border-radius !default;
 
 
 // Carousel
@@ -864,7 +898,7 @@ $carousel-control-icon-width:       20px !default;
 $carousel-control-prev-icon-bg:     str-replace(url("data:image/svg+xml;charset=utf8,%3Csvg xmlns='http://www.w3.org/2000/svg' fill='#{$carousel-control-color}' viewBox='0 0 8 8'%3E%3Cpath d='M5.25 0l-4 4 4 4 1.5-1.5-2.5-2.5 2.5-2.5-1.5-1.5z'/%3E%3C/svg%3E"), "#", "%23") !default;
 $carousel-control-next-icon-bg:     str-replace(url("data:image/svg+xml;charset=utf8,%3Csvg xmlns='http://www.w3.org/2000/svg' fill='#{$carousel-control-color}' viewBox='0 0 8 8'%3E%3Cpath d='M2.75 0l-1.5 1.5 2.5 2.5-2.5 2.5 1.5 1.5 4-4-4-4z'/%3E%3C/svg%3E"), "#", "%23") !default;
 
-$carousel-transition:               transform .6s ease !default;
+$carousel-transition:               transform .6s ease !default; // Define transform transition first if using multiple transitons (e.g., `transform 2s ease, opacity .5s ease-out`)
 
 
 // Close

src/sass/bootstrap4/bootstrap-grid.scss

@@ -1,5 +1,5 @@
 /*!
- * Bootstrap Grid v4.0.0 (https://getbootstrap.com)
+ * Bootstrap Grid v4.1.0 (https://getbootstrap.com/)
  * Copyright 2011-2018 The Bootstrap Authors
  * Copyright 2011-2018 Twitter, Inc.
  * Licensed under MIT (https://github.com/twbs/bootstrap/blob/master/LICENSE)

src/sass/bootstrap4/bootstrap-reboot.scss

@@ -1,5 +1,5 @@
 /*!
- * Bootstrap Reboot v4.0.0 (https://getbootstrap.com)
+ * Bootstrap Reboot v4.1.0 (https://getbootstrap.com/)
  * Copyright 2011-2018 The Bootstrap Authors
  * Copyright 2011-2018 Twitter, Inc.
  * Licensed under MIT (https://github.com/twbs/bootstrap/blob/master/LICENSE)

src/sass/bootstrap4/bootstrap.scss

@@ -1,5 +1,5 @@
 /*!
- * Bootstrap v4.0.0 (https://getbootstrap.com)
+ * Bootstrap v4.1.0 (https://getbootstrap.com/)
  * Copyright 2011-2018 The Bootstrap Authors
  * Copyright 2011-2018 Twitter, Inc.
  * Licensed under MIT (https://github.com/twbs/bootstrap/blob/master/LICENSE)

src/sass/bootstrap4/mixins/_caret.scss

@@ -14,6 +14,7 @@
 
 @mixin caret-right {
   border-top: $caret-width solid transparent;
+  border-right: 0;
   border-bottom: $caret-width solid transparent;
   border-left: $caret-width solid;
 }

src/sass/bootstrap4/mixins/_forms.scss

@@ -45,7 +45,7 @@
     margin-top: .1rem;
     font-size: .875rem;
     line-height: 1;
-    color: #fff;
+    color: $white;
     background-color: rgba($color, .8);
     border-radius: .2rem;
   }

src/sass/bootstrap4/mixins/_gradients.scss

@@ -11,7 +11,7 @@
 // Horizontal gradient, from left to right
 //
 // Creates two color stops, start and end, by specifying a color and position for each color stop.
-@mixin gradient-x($start-color: #555, $end-color: #333, $start-percent: 0%, $end-percent: 100%) {
+@mixin gradient-x($start-color: $gray-700, $end-color: $gray-800, $start-percent: 0%, $end-percent: 100%) {
   background-image: linear-gradient(to right, $start-color $start-percent, $end-color $end-percent);
   background-repeat: repeat-x;
 }
@@ -19,27 +19,27 @@
 // Vertical gradient, from top to bottom
 //
 // Creates two color stops, start and end, by specifying a color and position for each color stop.
-@mixin gradient-y($start-color: #555, $end-color: #333, $start-percent: 0%, $end-percent: 100%) {
+@mixin gradient-y($start-color: $gray-700, $end-color: $gray-800, $start-percent: 0%, $end-percent: 100%) {
   background-image: linear-gradient(to bottom, $start-color $start-percent, $end-color $end-percent);
   background-repeat: repeat-x;
 }
 
-@mixin gradient-directional($start-color: #555, $end-color: #333, $deg: 45deg) {
+@mixin gradient-directional($start-color: $gray-700, $end-color: $gray-800, $deg: 45deg) {
   background-image: linear-gradient($deg, $start-color, $end-color);
   background-repeat: repeat-x;
 }
-@mixin gradient-x-three-colors($start-color: #00b3ee, $mid-color: #7a43b6, $color-stop: 50%, $end-color: #c3325f) {
+@mixin gradient-x-three-colors($start-color: $blue, $mid-color: $purple, $color-stop: 50%, $end-color: $red) {
   background-image: linear-gradient(to right, $start-color, $mid-color $color-stop, $end-color);
   background-repeat: no-repeat;
 }
-@mixin gradient-y-three-colors($start-color: #00b3ee, $mid-color: #7a43b6, $color-stop: 50%, $end-color: #c3325f) {
+@mixin gradient-y-three-colors($start-color: $blue, $mid-color: $purple, $color-stop: 50%, $end-color: $red) {
   background-image: linear-gradient($start-color, $mid-color $color-stop, $end-color);
   background-repeat: no-repeat;
 }
-@mixin gradient-radial($inner-color: #555, $outer-color: #333) {
+@mixin gradient-radial($inner-color: $gray-700, $outer-color: $gray-800) {
   background-image: radial-gradient(circle, $inner-color, $outer-color);
   background-repeat: no-repeat;
 }
-@mixin gradient-striped($color: rgba(255,255,255,.15), $angle: 45deg) {
+@mixin gradient-striped($color: rgba($white, .15), $angle: 45deg) {
   background-image: linear-gradient($angle, $color 25%, transparent 25%, transparent 50%, $color 50%, $color 75%, transparent 75%, transparent);
 }

src/sass/bootstrap4/mixins/_hover.scss

@@ -1,9 +1,7 @@
-// stylelint-disable indentation
-
 // Hover mixin and `$enable-hover-media-query` are deprecated.
 //
 // Origally added during our alphas and maintained during betas, this mixin was
-// designed to prevent `:hover` stickiness on iOS—an issue where hover styles
+// designed to prevent `:hover` stickiness on iOS-an issue where hover styles
 // would persist after initial touch.
 //
 // For backward compatibility, we've kept these mixins and updated them to

src/sass/bootstrap4/mixins/_list-group.scss

@@ -12,7 +12,7 @@
       }
 
       &.active {
-        color: #fff;
+        color: $white;
         background-color: $color;
         border-color: $color;
       }

src/sass/bootstrap4/mixins/_nav-divider.scss

@@ -2,9 +2,9 @@
 //
 // Dividers (basically an hr) within dropdowns and nav lists
 
-@mixin nav-divider($color: #e5e5e5) {
+@mixin nav-divider($color: $nav-divider-color, $margin-y: $nav-divider-margin-y) {
   height: 0;
-  margin: ($spacer / 2) 0;
+  margin: $margin-y 0;
   overflow: hidden;
   border-top: 1px solid $color;
 }

src/sass/bootstrap4/mixins/_screen-reader.scss

@@ -1,6 +1,6 @@
 // Only display content to screen readers
 //
-// See: http://a11yproject.com/posts/how-to-hide-content/
+// See: https://a11yproject.com/posts/how-to-hide-content/
 // See: https://hugogiraudel.com/2016/10/13/css-hide-and-seek/
 
 @mixin sr-only {
@@ -11,7 +11,6 @@
   overflow: hidden;
   clip: rect(0, 0, 0, 0);
   white-space: nowrap;
-  clip-path: inset(50%);
   border: 0;
 }
 
@@ -30,6 +29,5 @@
     overflow: visible;
     clip: auto;
     white-space: normal;
-    clip-path: none;
   }
 }

src/sass/bootstrap4/mixins/_text-hide.scss

@@ -6,4 +6,6 @@
   text-shadow: none;
   background-color: transparent;
   border: 0;
+
+  @warn "The `text-hide()` mixin has been deprecated as of v4.1.0. It will be removed entirely in v5.";
 }

src/sass/bootstrap4/mixins/_transition.scss

@@ -6,4 +6,8 @@
       transition: $transition;
     }
   }
+
+  @media screen and (prefers-reduced-motion: reduce) {
+    transition: none;
+  }
 }

src/sass/bootstrap4/utilities/_flex.scss

@@ -16,6 +16,11 @@
     .flex#{$infix}-wrap         { flex-wrap: wrap !important; }
     .flex#{$infix}-nowrap       { flex-wrap: nowrap !important; }
     .flex#{$infix}-wrap-reverse { flex-wrap: wrap-reverse !important; }
+    .flex#{$infix}-fill         { flex: 1 1 auto !important; }
+    .flex#{$infix}-grow-0       { flex-grow: 0 !important; }
+    .flex#{$infix}-grow-1       { flex-grow: 1 !important; }
+    .flex#{$infix}-shrink-0     { flex-shrink: 0 !important; }
+    .flex#{$infix}-shrink-1     { flex-shrink: 1 !important; }
 
     .justify-content#{$infix}-start   { justify-content: flex-start !important; }
     .justify-content#{$infix}-end     { justify-content: flex-end !important; }

src/sass/bootstrap4/utilities/_position.scss

@@ -3,6 +3,7 @@
 // Common values
 
 // Sass list not in variables since it's not intended for customization.
+// stylelint-disable-next-line scss/dollar-variable-default
 $positions: static, relative, absolute, fixed, sticky;
 
 @each $position in $positions {

src/sass/bootstrap4/utilities/_shadows.scss

@@ -0,0 +1,6 @@
+// stylelint-disable declaration-no-important
+
+.shadow-sm { box-shadow: $box-shadow-sm !important; }
+.shadow { box-shadow: $box-shadow !important; }
+.shadow-lg { box-shadow: $box-shadow-lg !important; }
+.shadow-none { box-shadow: none !important; }

src/sass/bootstrap4/utilities/_text.scss

@@ -4,6 +4,8 @@
 // Text
 //
 
+.text-monospace { font-family: $font-family-monospace; }
+
 // Alignment
 
 .text-justify  { text-align: justify !important; }
@@ -37,14 +39,18 @@
 
 // Contextual colors
 
-.text-white { color: #fff !important; }
+.text-white { color: $white !important; }
 
 @each $color, $value in $theme-colors {
   @include text-emphasis-variant(".text-#{$color}", $value);
 }
 
+.text-body { color: $body-color !important; }
 .text-muted { color: $text-muted !important; }
 
+.text-black-50 { color: rgba($black, .5) !important; }
+.text-white-50 { color: rgba($white, .5) !important; }
+
 // Misc
 
 .text-hide {