diff --git a/theme/boost/scss/fontawesome.scss b/theme/boost/scss/fontawesome.scss
index ece05953e4f..fa4e5c8faf2 100644
--- a/theme/boost/scss/fontawesome.scss
+++ b/theme/boost/scss/fontawesome.scss
@@ -3,16 +3,16 @@
 $fa-version: "4.7.0" !default;
 
 @font-face {
-  font-family: 'FontAwesome';
-  src: url('[[font:core|fontawesome-webfont.eot]]?v=#{$fa-version}');
-  src: url('[[font:core|fontawesome-webfont.eot]]?#iefix&v=#{$fa-version}') format('embedded-opentype'),
-    url('[[font:core|fontawesome-webfont.woff2]]?v=#{$fa-version}') format('woff2'),
-    url('[[font:core|fontawesome-webfont.woff]]?v=#{$fa-version}') format('woff'),
-    url('[[font:core|fontawesome-webfont.ttf]]?v=#{$fa-version}') format('truetype'),
-    url('[[font:core|fontawesome-webfont.svg]]?v=#{$fa-version}#fontawesomeregular') format('svg');
-//  src: url('[[font:core|FontAwesome.otf]]') format('opentype'); // used when developing fonts
-  font-weight: normal;
-  font-style: normal;
+    font-family: 'FontAwesome';
+    src: url('[[font:core|fontawesome-webfont.eot]]?v=#{$fa-version}');
+    src:
+        url('[[font:core|fontawesome-webfont.eot]]?#iefix&v=#{$fa-version}') format('embedded-opentype'),
+        url('[[font:core|fontawesome-webfont.woff2]]?v=#{$fa-version}') format('woff2'),
+        url('[[font:core|fontawesome-webfont.woff]]?v=#{$fa-version}') format('woff'),
+        url('[[font:core|fontawesome-webfont.ttf]]?v=#{$fa-version}') format('truetype'),
+        url('[[font:core|fontawesome-webfont.svg]]?v=#{$fa-version}#fontawesomeregular') format('svg');
+    font-weight: normal;
+    font-style: normal;
 }
 
-@import "fontawesome/font-awesome";
\ No newline at end of file
+@import "fontawesome/font-awesome";
diff --git a/theme/boost/scss/moodle/backup-restore.scss b/theme/boost/scss/moodle/backup-restore.scss
index 282f0d45ef5..705d135e501 100644
--- a/theme/boost/scss/moodle/backup-restore.scss
+++ b/theme/boost/scss/moodle/backup-restore.scss
@@ -37,10 +37,6 @@
     .section_level .activity_level {
         font-weight: normal;
     }
-
-    .btn-cancel {
-        margin-right: auto !important;
-    }
 }
 
 /* Override the columns width to leave more room for the labels. */
diff --git a/theme/boost/scss/moodle/bs4alphacompat.scss b/theme/boost/scss/moodle/bs4alphacompat.scss
index 1c145880476..f3181caefc2 100644
--- a/theme/boost/scss/moodle/bs4alphacompat.scss
+++ b/theme/boost/scss/moodle/bs4alphacompat.scss
@@ -4,9 +4,11 @@ $font-size-root: $font-size-base;
 $zindex-navbar-fixed: 1030 !default;
 $tag-padding-y: .25rem !default;
 
+/* stylelint-disable function-url-scheme-blacklist */
 $form-icon-success: url("data:image/svg+xml;charset=utf8,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 8 8'%3E%3Cpath fill='%235cb85c' d='M2.3 6.73L.6 4.53c-.4-1.04.46-1.4 1.1-.8l1.1 1.4 3.4-3.8c.6-.63 1.6-.27 1.2.7l-4 4.6c-.43.5-.8.4-1.1.1z'/%3E%3C/svg%3E") !default;
 $form-icon-warning: url("data:image/svg+xml;charset=utf8,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 8 8'%3E%3Cpath fill='%23f0ad4e' d='M4.4 5.324h-.8v-2.46h.8zm0 1.42h-.8V5.89h.8zM3.76.63L.04 7.075c-.115.2.016.425.26.426h7.397c.242 0 .372-.226.258-.426C6.726 4.924 5.47 2.79 4.253.63c-.113-.174-.39-.174-.494 0z'/%3E%3C/svg%3E") !default;
 $form-icon-danger: url("data:image/svg+xml;charset=utf8,%3Csvg xmlns='http://www.w3.org/2000/svg' fill='%23d9534f' viewBox='-2 -2 7 7'%3E%3Cpath stroke='%23d9534f' d='M0 0l3 3m0-3L0 3'/%3E%3Ccircle r='.5'/%3E%3Ccircle cx='3' r='.5'/%3E%3Ccircle cy='3' r='.5'/%3E%3Ccircle cx='3' cy='3' r='.5'/%3E%3C/svg%3E") !default;
+/* stylelint-enable function-url-scheme-blacklist */
 
 $input-bg-disabled: $input-disabled-bg;
 $table-sm-cell-padding: $table-cell-padding-sm;
@@ -226,4 +228,4 @@ $bs4aspacers: map-merge((
     right: auto;
     left: 0;
 }
-*/
\ No newline at end of file
+*/
diff --git a/theme/boost/scss/moodle/core.scss b/theme/boost/scss/moodle/core.scss
index 30ab46e6f85..bbf579acfe7 100644
--- a/theme/boost/scss/moodle/core.scss
+++ b/theme/boost/scss/moodle/core.scss
@@ -2106,6 +2106,6 @@ $footer-link-color: $bg-inverse-link-color !default;
     }
 }
 
-.open.atto_menu>.dropdown-menu {
+.open.atto_menu > .dropdown-menu {
     display: block;
 }
diff --git a/theme/boost/scss/moodle/undo.scss b/theme/boost/scss/moodle/undo.scss
index 426f7d07105..cd44c0ecbb6 100644
--- a/theme/boost/scss/moodle/undo.scss
+++ b/theme/boost/scss/moodle/undo.scss
@@ -154,9 +154,11 @@ ol {
  * calc((0.5rem + 1px) * -1); is stripped out by lib/php-css-parser/Parser.php.
  * See MDL-61879. For now the arrow positions of popovers are fixed until this is resolved.
  */
- .bs-popover-right .arrow, .bs-popover-auto[x-placement^="right"] .arrow {
+.bs-popover-right .arrow,
+.bs-popover-auto[x-placement^="right"] .arrow {
     left: -9px;
- }
-  .bs-popover-left .arrow, .bs-popover-auto[x-placement^="left"] .arrow {
+}
+.bs-popover-left .arrow,
+.bs-popover-auto[x-placement^="left"] .arrow {
     right: -9px;
- }
+}
diff --git a/theme/boost/scss/preset/default.scss b/theme/boost/scss/preset/default.scss
index 8506f2e81ac..081b145259a 100644
--- a/theme/boost/scss/preset/default.scss
+++ b/theme/boost/scss/preset/default.scss
@@ -12,13 +12,13 @@ $gray-800: #373a3c !default;
 $gray-900: #212529 !default;
 $black:    #000 !default;
 
-$blue:    #3097D1 !default;
+$blue:    #3097d1 !default;
 $indigo:  #6610f2 !default;
 $purple:  #613d7c !default;
 $pink:    #e83e8c !default;
 $red:     #d9534f !default;
 $orange:  #f0ad4e !default;
-$yellow:  #FF7518 !default;
+$yellow:  #ff7518 !default;
 $green:   #5cb85c !default;
 $teal:    #20c997 !default;
 $cyan:    #5bc0de !default;
@@ -43,14 +43,14 @@ $font-size-base: 0.9375rem !default;
 $headings-font-weight:   300 !default;
 
 // Navbar
-$navbar-dark-hover-color:           rgba($white,1) !default;
-$navbar-light-hover-color:          rgba($black,.9) !default;
+$navbar-dark-hover-color:           rgba($white, 1) !default;
+$navbar-light-hover-color:          rgba($black, .9) !default;
 
 // Breadcrumbs
 $breadcrumb-padding-y:              .25rem !default;
-$breadcrumb-padding-x:              0rem !default;
+$breadcrumb-padding-x:              0 !default;
 $breadcrumb-item-padding:           .5rem !default;
-$breadcrumb-margin-bottom:          0rem !default;
+$breadcrumb-margin-bottom:          0 !default;
 $breadcrumb-bg:                     transparent !default;
 $breadcrumb-divider: "/" !default;
 $breadcrumb-divider-rtl: "/" !default;
@@ -59,14 +59,14 @@ $breadcrumb-divider-rtl: "/" !default;
 $alert-border-width:                0 !default;
 
 $theme-colors: (
-  primary: $primary,
-  secondary: $gray-200,
-  success: $success,
-  info: $info,
-  warning: $orange,
-  danger: $danger,
-  light: $gray-100,
-  dark: $gray-800
+    primary: $primary,
+    secondary: $gray-200,
+    success: $success,
+    info: $info,
+    warning: $orange,
+    danger: $danger,
+    light: $gray-100,
+    dark: $gray-800
 );
 
 // Import FontAwesome.
@@ -81,14 +81,15 @@ $theme-colors: (
 // Preset CSS
 
 body {
-  -webkit-font-smoothing: antialiased;
+    -webkit-font-smoothing: antialiased;
 }
 
 .navbar {
-    box-shadow: 0 2px 4px rgba(0,0,0,.08);
+    box-shadow: 0 2px 4px rgba(0, 0, 0, .08);
 }
 
-.filemanager-container, .filepicker-filelist {
+.filemanager-container,
+.filepicker-filelist {
     @extend .border;
 }