Merge branch 'v4-dev' into v4-navbars

25 files changed, 167 insertions, 123 deletions

diff --git a/scss/.scss-lint.yml b/scss/.scss-lint.yml
index 65c365ddb..9c6ac66ab 100644
--- a/scss/.scss-lint.yml
+++ b/scss/.scss-lint.yml
@@ -3,6 +3,9 @@ scss_files:
   - "**/*.scss"
   - "docs/assets/scss/**/*.scss"
 
+exclude:
+  - "scss/_normalize.scss"
+
 plugin_directories: ['.scss-linters']
 
 # List of gem names to load custom linters from (make sure they are already
diff --git a/scss/_animation.scss b/scss/_animation.scss
index edd7147e5..f0dfff81f 100644
--- a/scss/_animation.scss
+++ b/scss/_animation.scss
@@ -9,12 +9,21 @@
 
 .collapse {
   display: none;
-
   &.in {
     display: block;
   }
-  // tr&.in    { display: table-row; }
-  // tbody&.in { display: table-row-group; }
+}
+
+tr {
+  &.collapse.in {
+    display: table-row;
+  }
+}
+
+tbody {
+  &.collapse.in {
+    display: table-row-group;
+  }
 }
 
 .collapsing {
diff --git a/scss/_custom-forms.scss b/scss/_custom-forms.scss
index fe30f9fad..30b46083b 100644
--- a/scss/_custom-forms.scss
+++ b/scss/_custom-forms.scss
@@ -2,7 +2,7 @@
 
 // Embedded icons from Open Iconic.
 // Released under MIT and copyright 2014 Waybury.
-// http://useiconic.com/open
+// https://useiconic.com/open
 
 
 // Checkboxes and radios
diff --git a/scss/_images.scss b/scss/_images.scss
index 989426999..3cdedc4ff 100644
--- a/scss/_images.scss
+++ b/scss/_images.scss
@@ -6,13 +6,9 @@
 // which weren't expecting the images within themselves to be involuntarily resized.
 // See also https://github.com/twbs/bootstrap/issues/18178
 .img-fluid {
-  @include img-fluid();
+  @include img-fluid;
 }
 
-// Rounded corners
-.img-rounded {
-  @include border-radius($border-radius-lg);
-}
 
 // Image thumbnails
 .img-thumbnail {
@@ -24,12 +20,7 @@
   @include box-shadow($thumbnail-box-shadow);
 
   // Keep them at most 100% wide
-  @include img-fluid(inline-block);
-}
-
-// Perfect circle
-.img-circle {
-  border-radius: 50%;
+  @include img-fluid;
 }
 
 //
diff --git a/scss/_mixins.scss b/scss/_mixins.scss
index 1b5bf0fae..e53ab3414 100644
--- a/scss/_mixins.scss
+++ b/scss/_mixins.scss
@@ -51,4 +51,4 @@
 // @import "mixins/navbar-align";
 @import "mixins/grid-framework";
 @import "mixins/grid";
-@import "mixins/pulls";
+@import "mixins/float";
diff --git a/scss/_modal.scss b/scss/_modal.scss
index e4a04e45e..c326d5699 100644
--- a/scss/_modal.scss
+++ b/scss/_modal.scss
@@ -22,7 +22,9 @@
   // Prevent Chrome on Windows from adding a focus outline. For details, see
   // https://github.com/twbs/bootstrap/pull/10951.
   outline: 0;
-  -webkit-overflow-scrolling: touch;
+  // We deliberately don't use `-webkit-overflow-scrolling: touch;` due to a
+  // gnarly iOS Safari bug: https://bugs.webkit.org/show_bug.cgi?id=158342
+  // See also https://github.com/twbs/bootstrap/issues/17695
 
   // When fading in the modal, animate it to slide down
   &.fade .modal-dialog {
diff --git a/scss/_normalize.scss b/scss/_normalize.scss
index 8a74836b0..827b7f31a 100644
--- a/scss/_normalize.scss
+++ b/scss/_normalize.scss
@@ -1,14 +1,16 @@
-/*! normalize.css v4.0.0 | MIT License | github.com/necolas/normalize.css */
+/*! normalize.css v4.2.0 | MIT License | github.com/necolas/normalize.css */
 
 //
 // 1. Change the default font family in all browsers (opinionated).
-// 2. Prevent adjustments of font size after orientation changes in IE and iOS.
+// 2. Correct the line height in all browsers.
+// 3. Prevent adjustments of font size after orientation changes in IE and iOS.
 //
 
 html {
   font-family: sans-serif; // 1
-  -ms-text-size-adjust: 100%; // 2
-  -webkit-text-size-adjust: 100%; // 2
+  line-height: 1.15; // 2
+  -ms-text-size-adjust: 100%; // 3
+  -webkit-text-size-adjust: 100%; // 3
 }
 
 //
@@ -76,7 +78,7 @@ progress {
 // 1. Add the correct display in IE.
 //
 
-template, // 2
+template, // 1
 [hidden] {
   display: none;
 }
@@ -85,11 +87,13 @@ template, // 2
 // ==========================================================================
 
 //
-// Remove the gray background on active links in IE 10.
+// 1. Remove the gray background on active links in IE 10.
+// 2. Remove gaps in links underline in iOS 8+ and Safari 8+.
 //
 
 a {
-  background-color: transparent;
+  background-color: transparent; // 1
+  -webkit-text-decoration-skip: objects; // 2
 }
 
 //
@@ -248,14 +252,17 @@ hr {
 // ==========================================================================
 
 //
-// Change font properties to `inherit` in all browsers (opinionated).
+// 1. Change font properties to `inherit` in all browsers (opinionated).
+// 2. Remove the margin in Firefox and Safari.
 //
 
 button,
 input,
+optgroup,
 select,
 textarea {
-  font: inherit;
+  font: inherit; // 1
+  margin: 0; // 2
 }
 
 //
@@ -269,30 +276,16 @@ optgroup {
 //
 // Show the overflow in IE.
 // 1. Show the overflow in Edge.
-// 2. Show the overflow in Edge, Firefox, and IE.
 //
 
 button,
-input, // 1
-select { // 2
+input { // 1
   overflow: visible;
 }
 
 //
-// Remove the margin in Safari.
-// 1. Remove the margin in Firefox and Safari.
-//
-
-button,
-input,
-select,
-textarea { // 1
-  margin: 0;
-}
-
-//
-// Remove the inheritence of text transform in Edge, Firefox, and IE.
-// 1. Remove the inheritence of text transform in Firefox.
+// Remove the inheritance of text transform in Edge, Firefox, and IE.
+// 1. Remove the inheritance of text transform in Firefox.
 //
 
 button,
@@ -301,28 +294,9 @@ select { // 1
 }
 
 //
-// Change the cursor in all browsers (opinionated).
-//
-
-button,
-[type="button"],
-[type="reset"],
-[type="submit"] {
-  cursor: pointer;
-}
-
-//
-// Restore the default cursor to disabled elements unset by the previous rule.
-//
-
-[disabled] {
-  cursor: default;
-}
-
-//
 // 1. Prevent a WebKit bug where (2) destroys native `audio` and `video`
 //    controls in Android 4.
-// 2. Correct the inability to style clickable types in iOS.
+// 2. Correct the inability to style clickable types in iOS and Safari.
 //
 
 button,
@@ -337,8 +311,10 @@ html [type="button"], // 1
 //
 
 button::-moz-focus-inner,
-input::-moz-focus-inner {
-  border: 0;
+[type="button"]::-moz-focus-inner,
+[type="reset"]::-moz-focus-inner,
+[type="submit"]::-moz-focus-inner {
+  border-style: none;
   padding: 0;
 }
 
@@ -347,7 +323,9 @@ input::-moz-focus-inner {
 //
 
 button:-moz-focusring,
-input:-moz-focusring {
+[type="button"]:-moz-focusring,
+[type="reset"]:-moz-focusring,
+[type="submit"]:-moz-focusring {
   outline: 1px dotted ButtonText;
 }
 
@@ -406,19 +384,39 @@ textarea {
 }
 
 //
-// Correct the odd appearance of search inputs in Chrome and Safari.
+// 1. Correct the odd appearance in Chrome and Safari.
+// 2. Correct the outline style in Safari.
 //
 
 [type="search"] {
-  -webkit-appearance: textfield;
+  -webkit-appearance: textfield; // 1
+  outline-offset: -2px; // 2
 }
 
 //
-// Remove the inner padding and cancel buttons in Chrome on OS X and
-// Safari on OS X.
+// Remove the inner padding and cancel buttons in Chrome and Safari on OS X.
 //
 
 [type="search"]::-webkit-search-cancel-button,
 [type="search"]::-webkit-search-decoration {
   -webkit-appearance: none;
 }
+
+//
+// Correct the text style of placeholders in Chrome, Edge, and Safari.
+//
+
+::-webkit-input-placeholder {
+  color: inherit;
+  opacity: 0.54;
+}
+
+//
+// 1. Correct the inability to style clickable types in iOS and Safari.
+// 2. Change font properties to `inherit` in Safari.
+//
+
+::-webkit-file-upload-button {
+  -webkit-appearance: button; // 1
+  font: inherit; // 2
+}
diff --git a/scss/_print.scss b/scss/_print.scss
index 84556602f..bd41328c2 100644
--- a/scss/_print.scss
+++ b/scss/_print.scss
@@ -14,7 +14,10 @@
     *::before,
     *::after,
     *::first-letter,
-    *::first-line {
+    p::first-line,
+    div::first-line,
+    blockquote::first-line,
+    li::first-line {
       // Bootstrap specific; comment out `color` and `background`
       //color: #000 !important; // Black prints faster:
                                 //   http://www.sanbeiji.com/archives/953
@@ -45,9 +48,12 @@
 
     //a[href^="#"]::after,
     //a[href^="javascript:"]::after {
-    //  content: "";
+    // content: "";
     //}
 
+    pre {
+      white-space: pre-wrap !important;
+    }
     pre,
     blockquote {
       border: $border-width solid #999;   // Bootstrap custom code; using `$border-width` instead of 1px
diff --git a/scss/_reboot.scss b/scss/_reboot.scss
index a24c3d3fa..461ca40e6 100644
--- a/scss/_reboot.scss
+++ b/scss/_reboot.scss
@@ -15,7 +15,7 @@
 //
 // Heads up! This reset may cause conflicts with some third-party widgets. For
 // recommendations on resolving such conflicts, see
-// http://getbootstrap.com/getting-started/#third-box-sizing.
+// https://getbootstrap.com/getting-started/#third-box-sizing.
 //
 // Credit: https://css-tricks.com/inheriting-box-sizing-probably-slightly-better-best-practice/
 
@@ -33,15 +33,15 @@ html {
 // Make viewport responsive
 //
 // @viewport is needed because IE 10+ doesn't honor <meta name="viewport"> in
-// some cases. See http://timkadlec.com/2012/10/ie10-snap-mode-and-responsive-design/.
+// some cases. See https://timkadlec.com/2012/10/ie10-snap-mode-and-responsive-design/.
 // Eventually @viewport will replace <meta name="viewport">.
 //
 // However, `device-width` is broken on IE 10 on Windows (Phone) 8,
-// (see http://timkadlec.com/2013/01/windows-phone-8-and-device-width/ and https://github.com/twbs/bootstrap/issues/10497)
+// (see https://timkadlec.com/2013/01/windows-phone-8-and-device-width/ and https://github.com/twbs/bootstrap/issues/10497)
 // and the fix for that involves a snippet of JavaScript to sniff the user agent
 // and apply some conditional CSS.
 //
-// See http://getbootstrap.com/getting-started/#support-ie10-width for the relevant hack.
+// See https://getbootstrap.com/getting-started/#support-ie10-width for the relevant hack.
 //
 // Wrap `@viewport` with `@at-root` for when folks do a nested import (e.g.,
 // `.class-name { @import "bootstrap"; }`).
@@ -247,9 +247,9 @@ img {
 // DON'T remove the click delay when `<meta name="viewport" content="width=device-width">` is present.
 // However, they DO support removing the click delay via `touch-action: manipulation`.
 // See:
-// * http://v4-alpha.getbootstrap.com/content/reboot/#click-delay-optimization-for-touch
+// * https://v4-alpha.getbootstrap.com/content/reboot/#click-delay-optimization-for-touch
 // * http://caniuse.com/#feat=css-touch-action
-// * http://patrickhlauke.github.io/touch/tests/results/#suppressing-300ms-delay
+// * https://patrickhlauke.github.io/touch/tests/results/#suppressing-300ms-delay
 
 a,
 area,
@@ -312,11 +312,8 @@ input,
 button,
 select,
 textarea {
-  // Remove all `margin`s so our classes don't have to do it themselves.
-  margin: 0;
   // Normalize includes `font: inherit;`, so `font-family`. `font-size`, etc are
-  // properly inherited. However, `line-height` isn't addressed there. Using this
-  // ensures we don't need to unnecessarily redeclare the global font stack.
+  // properly inherited. However, `line-height` isn't inherited there.
   line-height: inherit;
 }
 
diff --git a/scss/_type.scss b/scss/_type.scss
index ff7114074..e0be5193c 100644
--- a/scss/_type.scss
+++ b/scss/_type.scss
@@ -60,7 +60,7 @@ hr {
 
 small,
 .small {
-  font-size: $small-font-size;
+  font-size: $font-size-sm;
   font-weight: normal;
 }
 
diff --git a/scss/_utilities.scss b/scss/_utilities.scss
index 87b8ba6da..aef99aeba 100644
--- a/scss/_utilities.scss
+++ b/scss/_utilities.scss
@@ -1,8 +1,9 @@
 @import "utilities/background";
+@import "utilities/borders";
 @import "utilities/clearfix";
 @import "utilities/display";
 @import "utilities/flex";
-@import "utilities/pulls";
+@import "utilities/float";
 @import "utilities/screenreaders";
 @import "utilities/spacing";
 @import "utilities/text";
diff --git a/scss/_variables.scss b/scss/_variables.scss
index 08d372d80..754c3d35e 100644
--- a/scss/_variables.scss
+++ b/scss/_variables.scss
@@ -125,7 +125,7 @@ $link-hover-decoration: underline !default;
 
 $grid-breakpoints: (
   xs: 0,
-  sm: 544px,
+  sm: 576px,
   md: 768px,
   lg: 992px,
   xl: 1200px
@@ -138,9 +138,9 @@ $grid-breakpoints: (
 // Define the maximum width of `.container` for different screen sizes.
 
 $container-max-widths: (
-  sm: 576px,
+  sm: 540px,
   md: 720px,
-  lg: 940px,
+  lg: 960px,
   xl: 1140px
 ) !default;
 @include _assert-ascending($container-max-widths, "$container-max-widths");
@@ -205,8 +205,6 @@ $headings-color:         inherit !default;
 $lead-font-size:   1.25rem !default;
 $lead-font-weight: 300 !default;
 
-$small-font-size: 80% !default;
-
 $text-muted: $gray-light !default;
 
 $abbr-border-color: $gray-light !default;
diff --git a/scss/bootstrap.scss b/scss/bootstrap.scss
index 219eda217..ce61be8eb 100644
--- a/scss/bootstrap.scss
+++ b/scss/bootstrap.scss
@@ -1,5 +1,5 @@
 /*!
- * Bootstrap v4.0.0-alpha.4 (http://getbootstrap.com)
+ * Bootstrap v4.0.0-alpha.4 (https://getbootstrap.com)
  * Copyright 2011-2016 The Bootstrap Authors
  * Copyright 2011-2016 Twitter, Inc.
  * Licensed under MIT (https://github.com/twbs/bootstrap/blob/master/LICENSE)
diff --git a/scss/mixins/_background-variant.scss b/scss/mixins/_background-variant.scss
index ff21ad958..54a734dcc 100644
--- a/scss/mixins/_background-variant.scss
+++ b/scss/mixins/_background-variant.scss
@@ -2,7 +2,6 @@
 
 @mixin bg-variant($parent, $color) {
   #{$parent} {
-    color: #fff !important;
     background-color: $color !important;
   }
   a#{$parent} {
diff --git a/scss/mixins/_pulls.scss b/scss/mixins/_float.scss
index 6bdff025d..b30cf1468 100644
--- a/scss/mixins/_pulls.scss
+++ b/scss/mixins/_float.scss
@@ -1,6 +1,6 @@
-@mixin pull-left {
+@mixin float-left {
   float: left !important;
 }
-@mixin pull-right {
+@mixin float-right {
   float: right !important;
 }
diff --git a/scss/mixins/_grid-framework.scss b/scss/mixins/_grid-framework.scss
index 0e3852e24..35ccd9221 100644
--- a/scss/mixins/_grid-framework.scss
+++ b/scss/mixins/_grid-framework.scss
@@ -21,6 +21,11 @@
   @each $breakpoint in map-keys($breakpoints) {
     $breakpoint-counter: ($breakpoint-counter + 1);
 
+    // Allow columns to stretch full width below their breakpoints
+    .col-#{$breakpoint} {
+      @extend %grid-column;
+    }
+
     @for $i from 1 through $columns {
       .col-#{$breakpoint}-#{$i} {
         @extend %grid-column;
@@ -31,11 +36,9 @@
       // Provide basic `.col-{bp}` classes for equal-width flexbox columns
       @if $enable-flex {
         .col-#{$breakpoint} {
-          position: relative;
           flex-basis: 0;
           flex-grow: 1;
           max-width: 100%;
-          min-height: 1px;
         }
       }
 
diff --git a/scss/mixins/_grid.scss b/scss/mixins/_grid.scss
index b381ba900..88cbd249a 100644
--- a/scss/mixins/_grid.scss
+++ b/scss/mixins/_grid.scss
@@ -17,7 +17,8 @@
 @mixin make-container-max-widths($max-widths: $container-max-widths, $breakpoints: $grid-breakpoints) {
   @each $breakpoint, $container-max-width in $max-widths {
     @include media-breakpoint-up($breakpoint, $breakpoints) {
-      max-width: $container-max-width;
+      width: $container-max-width;
+      max-width: 100%;
     }
   }
 }
diff --git a/scss/mixins/_hover.scss b/scss/mixins/_hover.scss
index 4a648a54d..6dd55e705 100644
--- a/scss/mixins/_hover.scss
+++ b/scss/mixins/_hover.scss
@@ -1,7 +1,7 @@
 @mixin hover {
   // TODO: re-enable along with mq4-hover-shim
 //  @if $enable-hover-media-query {
-//    // See Media Queries Level 4: http://drafts.csswg.org/mediaqueries/#hover
+//    // See Media Queries Level 4: https://drafts.csswg.org/mediaqueries/#hover
 //    // Currently shimmed by https://github.com/twbs/mq4-hover-shim
 //    @media (hover: hover) {
 //      &:hover { @content }
diff --git a/scss/mixins/_image.scss b/scss/mixins/_image.scss
index 91d2f59ee..c2b45f2ce 100644
--- a/scss/mixins/_image.scss
+++ b/scss/mixins/_image.scss
@@ -7,10 +7,12 @@
 //
 // Keep images from scaling beyond the width of their parents.
 
-@mixin img-fluid($display: block) {
-  display: $display;
-  max-width: 100%; // Part 1: Set a maximum relative to the parent
-  height: auto; // Part 2: Scale the height according to the width, otherwise you get stretching
+@mixin img-fluid {
+  // Part 1: Set a maximum relative to the parent
+  max-width: 100%;
+  // Part 2: Override the height to auto, otherwise images will be stretched
+  // when setting a width and height attribute on the img element.
+  height: auto;
 }
 
 
diff --git a/scss/mixins/_screen-reader.scss b/scss/mixins/_screen-reader.scss
index 6ae65516a..c20858324 100644
--- a/scss/mixins/_screen-reader.scss
+++ b/scss/mixins/_screen-reader.scss
@@ -15,7 +15,7 @@
 
 // Use in conjunction with .sr-only to only display content when it's focused.
 //
-// Useful for "Skip to main content" links; see http://www.w3.org/TR/2013/NOTE-WCAG20-TECHS-20130905/G1
+// Useful for "Skip to main content" links; see https://www.w3.org/TR/2013/NOTE-WCAG20-TECHS-20130905/G1
 //
 // Credit: HTML5 Boilerplate
 
diff --git a/scss/utilities/_borders.scss b/scss/utilities/_borders.scss
new file mode 100644
index 000000000..b2e70aaf5
--- /dev/null
+++ b/scss/utilities/_borders.scss
@@ -0,0 +1,30 @@
+//
+// Border-width
+//
+
+// TBD...?
+
+
+//
+// Border-radius
+//
+
+.rounded {
+  @include border-radius($border-radius);
+}
+.rounded-top {
+  @include border-top-radius($border-radius);
+}
+.rounded-right {
+  @include border-right-radius($border-radius);
+}
+.rounded-bottom {
+  @include border-bottom-radius($border-radius);
+}
+.rounded-left {
+  @include border-left-radius($border-radius);
+}
+
+.rounded-circle {
+  border-radius: 50%;
+}
diff --git a/scss/utilities/_float.scss b/scss/utilities/_float.scss
new file mode 100644
index 000000000..eea34bff2
--- /dev/null
+++ b/scss/utilities/_float.scss
@@ -0,0 +1,13 @@
+@each $breakpoint in map-keys($grid-breakpoints) {
+  @include media-breakpoint-up($breakpoint) {
+    .float-#{$breakpoint}-left {
+      @include float-left();
+    }
+    .float-#{$breakpoint}-right {
+      @include float-right();
+    }
+    .float-#{$breakpoint}-none {
+      float: none !important;
+    }
+  }
+}
diff --git a/scss/utilities/_pulls.scss b/scss/utilities/_pulls.scss
deleted file mode 100644
index 7fec56c9a..000000000
--- a/scss/utilities/_pulls.scss
+++ /dev/null
@@ -1,13 +0,0 @@
-@each $breakpoint in map-keys($grid-breakpoints) {
-  @include media-breakpoint-up($breakpoint) {
-    .pull-#{$breakpoint}-left {
-      @include pull-left();
-    }
-    .pull-#{$breakpoint}-right {
-      @include pull-right();
-    }
-    .pull-#{$breakpoint}-none {
-      float: none !important;
-    }
-  }
-}
diff --git a/scss/utilities/_spacing.scss b/scss/utilities/_spacing.scss
index b7ff044b6..c81a6aa88 100644
--- a/scss/utilities/_spacing.scss
+++ b/scss/utilities/_spacing.scss
@@ -4,7 +4,7 @@
 
 // Margin and Padding
 
-.m-x-auto {
+.mx-auto {
   margin-right: auto !important;
   margin-left:  auto !important;
 }
@@ -14,18 +14,18 @@
     $length-x:   map-get($lengths, x);
     $length-y:   map-get($lengths, y);
 
-    .#{$abbrev}-a-#{$size} { #{$prop}:        $length-y $length-x !important; } // a = All sides
-    .#{$abbrev}-t-#{$size} { #{$prop}-top:    $length-y !important; }
-    .#{$abbrev}-r-#{$size} { #{$prop}-right:  $length-x !important; }
-    .#{$abbrev}-b-#{$size} { #{$prop}-bottom: $length-y !important; }
-    .#{$abbrev}-l-#{$size} { #{$prop}-left:   $length-x !important; }
+    .#{$abbrev}-#{$size} { #{$prop}:        $length-y $length-x !important; } // a = All sides
+    .#{$abbrev}t-#{$size} { #{$prop}-top:    $length-y !important; }
+    .#{$abbrev}r-#{$size} { #{$prop}-right:  $length-x !important; }
+    .#{$abbrev}b-#{$size} { #{$prop}-bottom: $length-y !important; }
+    .#{$abbrev}l-#{$size} { #{$prop}-left:   $length-x !important; }
 
     // Axes
-    .#{$abbrev}-x-#{$size} {
+    .#{$abbrev}x-#{$size} {
       #{$prop}-right:  $length-x !important;
       #{$prop}-left:   $length-x !important;
     }
-    .#{$abbrev}-y-#{$size} {
+    .#{$abbrev}y-#{$size} {
       #{$prop}-top:    $length-y !important;
       #{$prop}-bottom: $length-y !important;
     }
diff --git a/scss/utilities/_text.scss b/scss/utilities/_text.scss
index c1cbe1270..b4468e98d 100644
--- a/scss/utilities/_text.scss
+++ b/scss/utilities/_text.scss
@@ -32,6 +32,10 @@
 
 // Contextual colors
 
+.text-white {
+  color: #fff !important;
+}
+
 @include text-emphasis-variant('.text-muted', $text-muted);
 
 @include text-emphasis-variant('.text-primary', $brand-primary);