DEV: Refactor `scale-color()` usage in SCSS

DEV: Refactor scale-color() usage in SCSS

diff --git a/app/assets/stylesheets/common/base/discourse.scss b/app/assets/stylesheets/common/base/discourse.scss
index 5360b11..142a80d 100644
--- a/app/assets/stylesheets/common/base/discourse.scss
+++ b/app/assets/stylesheets/common/base/discourse.scss
@@ -152,10 +152,7 @@ input {
   }
 
   &.invalid {
-    background-color: dark-light-choose(
-      $danger-low,
-      scale-color($danger, $lightness: -60%)
-    );
+    background-color: $danger-low;
   }
 
   .radio &[type="radio"],
diff --git a/app/assets/stylesheets/common/base/topic-post.scss b/app/assets/stylesheets/common/base/topic-post.scss
index ced3bf8..634dc45 100644
--- a/app/assets/stylesheets/common/base/topic-post.scss
+++ b/app/assets/stylesheets/common/base/topic-post.scss
@@ -125,16 +125,10 @@ $quote-share-maxwidth: 150px;
   }
 
   ins {
-    background-color: dark-light-choose(
-      $success-low,
-      scale-color($success, $lightness: -60%)
-    );
+    background-color: $success-low;
   }
   del {
-    background-color: dark-light-choose(
-      $danger-low,
-      scale-color($danger, $lightness: -60%)
-    );
+    background-color: $danger-low;
   }
   // Prevents users from breaking posts with tag nesting
   big {
diff --git a/app/assets/stylesheets/common/base/upload.scss b/app/assets/stylesheets/common/base/upload.scss
index c7b010f..9116495 100644
--- a/app/assets/stylesheets/common/base/upload.scss
+++ b/app/assets/stylesheets/common/base/upload.scss
@@ -1,5 +1,5 @@
 .uploaded-image-preview {
-  background: $primary center;
+  background: $primary-medium center;
   background-size: cover;
   position: relative;
 
diff --git a/app/assets/stylesheets/common/components/user-stream-item.scss b/app/assets/stylesheets/common/components/user-stream-item.scss
index 22e0551..79b2e9e 100644
--- a/app/assets/stylesheets/common/components/user-stream-item.scss
+++ b/app/assets/stylesheets/common/components/user-stream-item.scss
@@ -76,10 +76,7 @@
   }
 
   .edit-reason {
-    background-color: dark-light-choose(
-      $highlight-medium,
-      scale-color($highlight, $lightness: -50%)
-    );
+    background-color: $highlight-medium;
     padding: 3px 5px 5px 5px;
   }
 

GitHub sha: 29276a37