Ticket #48709: 48709.diff

src/wp-admin/css/colors/_mixins.scss

@@ -39 +39 @@
         &:disabled,
         &.button-primary-disabled,
         &.disabled {
-                color: hsl( hue( $button-color ), 10%, 80% ) !important;
+                color: $button-disabled-color !important;
                 background: darken( $button-color, 8% ) !important;
                 border-color: darken( $button-color, 8% ) !important;
                 text-shadow: none !important;

src/wp-admin/css/colors/_variables.scss

@@ -19 +19 @@
 
 $button-color: $highlight-color !default;
 $button-text-color: $text-color !default;
+$button-disabled-color: rgba($text-color, 0.5) !default;
 
 $form-checked: #7e8993 !default;