diff --git a/scss/_variables.scss b/scss/_variables.scss
index b73024427c86..5782bbb74bdc 100644
--- a/scss/_variables.scss
+++ b/scss/_variables.scss
@@ -186,18 +186,13 @@ $paragraph-margin-bottom:   1rem !default;
 // Define the minimum dimensions at which your layout will change,
 // adapting to different screen sizes, for use in media queries.
 
-$grid-breakpoints: () !default;
-// stylelint-disable-next-line scss/dollar-variable-default
-$grid-breakpoints: map-merge(
-  (
-    xs: 0,
-    sm: 576px,
-    md: 768px,
-    lg: 992px,
-    xl: 1200px
-  ),
-  $grid-breakpoints
-);
+$grid-breakpoints: (
+  xs: 0,
+  sm: 576px,
+  md: 768px,
+  lg: 992px,
+  xl: 1200px
+) !default;
 
 @include _assert-ascending($grid-breakpoints, "$grid-breakpoints");
 @include _assert-starts-at-zero($grid-breakpoints);
@@ -207,17 +202,12 @@ $grid-breakpoints: map-merge(
 //
 // Define the maximum width of `.container` for different screen sizes.
 
-$container-max-widths: () !default;
-// stylelint-disable-next-line scss/dollar-variable-default
-$container-max-widths: map-merge(
-  (
-    sm: 540px,
-    md: 720px,
-    lg: 960px,
-    xl: 1140px
-  ),
-  $container-max-widths
-);
+$container-max-widths: (
+  sm: 540px,
+  md: 720px,
+  lg: 960px,
+  xl: 1140px
+) !default;
 
 @include _assert-ascending($container-max-widths, "$container-max-widths");