Dark theme for changelog

really quick fix just 3 sloc

src/css/states/preload.scss

@@ -14,6 +14,10 @@
         padding: 10px;
         box-sizing: border-box;
         background: #eef1f4;
+        
+        @include DarkThemeOverride {
+            background: #424242;
+        }
 
         .version {
             @include Heading;