css: standardize success/error background colors.

Standardize background colors to light green or light red in several places:

* Modqueue positive/negative score backgrounds.
* Modqueue quality/sample warning backgrounds.
* User feedback positive/negative backgrounds.
* Ban expired/unexpired backgrounds.
* Flag resolved/unresolved backgrounds (removed; resolved flags no
  longer have a grey background because of inconsistencies in what
  resolved means).

app/javascript/src/styles/base/040_colors.css

@@ -1,11 +1,15 @@
 :root {
   --body-background-color: white;
 
-  --fineprint-color: #888;
-
   --link-color: hsl(213, 100%, 50%);
   --link-hover-color: hsl(213, 100%, 75%);
 
+  --fineprint-color: #888;
+
+  --error-background-color: hsl(0, 100%, 95%); // light red
+  --success-background-color: hsl(120, 100%, 95%); // light green
+  --warning-background-color: hsl(50, 100%, 95%); // light yellow
+
   --subnav-menu-background-color: #F5F5FF;
 
   --responsive-menu-background-color: var(--link-hover-color);
@@ -32,10 +36,10 @@
   --preview-icon-color: white;
   --preview-icon-background: rgba(0, 0, 0, 0.5);
 
-  --modqueue-sample-warning-color: hsl(0,  100%, 90%); // light red
-  --modqueue-quality-warning-color: hsl(50, 100%, 90%); // light yellow
-  --modqueue-postive-score-background-color: rgb(230, 255, 230);
-  --modqueue-negative-score-background-color: rgb(255, 230, 230);
+  --modqueue-sample-warning-color: var(--error-background-color);
+  --modqueue-quality-warning-color: var(--warning-background-color);
+  --modqueue-postive-score-background-color: var(--success-background-color);
+  --modqueue-negative-score-background-color: var(--error-background-color);
 
   --uploads-dropzone-border: 4xp dashed #DDD;
   --uploads-dropzone-placeholder-color: #333;
@@ -73,11 +77,6 @@
 
   --preview-current-post-background: rgba(0, 0, 0, 0.1);
 
-  --error-color: hsl(0, 100%, 95%); // light red
-  --error-hover-color: hsl(0, 100%, 90%);
-  --success-color: hsl(120, 100%, 95%); // light green
-  --success-hover-color: hsl(120, 100%, 90%);
-
   --autocomplete-background-color: #F0F0F0;
   --autocomplete-border-color: #C5C5C5;
 
@@ -124,12 +123,6 @@
   --note-highlight-color: blue;
   --note-tn-color: gray;
 
-  --post-events-resolved-background: #DDD;
-  --post-events-unresolved-background: white;
-
-  --user-name-change-requests-positive-background: #DDFFDD;
-  --user-name-change-requests-negative-background: #FFDDDD;
-
   --series-pool-color: #A0A;
   --series-pool-hover-color: #B6B;
 
@@ -175,8 +168,6 @@
   --keyboard-shortcut-color: white;
   --keyboard-shortcut-background-color: #333;
 
-  // XXX unused?
-  --error-color: red;
   --error-message-color: #A00;
 
   --new-artist-color: #A00;
@@ -219,10 +210,6 @@
 
   --wiki-page-other-name-background-color: #EEE;
 
-  --user-feedback-positive-background-color: #DDFFDD !important;
-  --user-feedback-negative-background-color: #FFDDDD !important;
-  --user-feedback-neutral-background-color: #FFFFFF !important;
-
   --paginator-ellipsis-color: grey;
   --paginator-arrow-background-color: white;
   --paginator-arrow-color: var(--link-color);

app/javascript/src/styles/specific/bans.scss

@@ -1,17 +1,9 @@
 #c-bans #a-index {
   tr[data-expired="true"] {
-    background-color: var(--success-color) !important;
-
-    &:hover {
-      background-color: var(--success-hover-color) !important;
-    }
+    background-color: var(--success-background-color);
   }
 
   tr[data-expired="false"] {
-    background-color: var(--error-color) !important;
-
-    &:hover {
-      background-color: var(--error-hover-color) !important;
-    }
+    background-color: var(--error-background-color);
   }
 }

app/javascript/src/styles/specific/post_events.scss

@@ -1,11 +0,0 @@
-div#c-post-events {
-  #a-index {
-    tr.resolved-true {
-      background: var(--post-events-resolved-background);
-    }
-
-    tr.resolved-false {
-      background: var(--post-events-unresolved-background);
-    }
-  }
-}

app/javascript/src/styles/specific/post_flags.scss

@@ -1,9 +0,0 @@
-div#c-post-flags {
-  tr.resolved-true {
-    background: var(--post-events-resolved-background) !important;
-  }
-
-  tr.resolved-false {
-    background: var(--post-events-unresolved-background) !important;
-  }
-}

app/javascript/src/styles/specific/user_feedback.scss

@@ -1,14 +1,10 @@
 div#c-user-feedbacks, div#c-moderator-dashboards div#col2 {
   .feedback-category-positive {
-    background: var(--user-feedback-positive-background-color);
+    background: var(--success-background-color);
   }
 
   .feedback-category-negative {
-    background: var(--user-feedback-negative-background-color);
-  }
-
-  .feedback-category-neutral {
-    background: var(--user-feedback-neutral-background-color);
+    background: var(--error-background-color);
   }
 
   #negative-policy {

app/javascript/src/styles/specific/user_name_change_requests.scss

@@ -1,10 +1,10 @@
 #c-user-name-change-requests {
   .feedback-category-positive {
-    background: var(--user-name-change-requests-positive-background) !important;
+    background: var(--success-background-color);
   }
 
   .feedback-category-negative {
-    background: var(--user-name-change-requests-negative-background) !important;
+    background: var(--error-background-color);
   }
   
   li {