darken header

Author: JHWelch

src/ui/css/diff2html.css

@@ -52,7 +52,7 @@
 
   --d2h-dark-line-border-color: #5a5c51;
 
-  --d2h-dark-file-header-bg-color: #4f5146;
+  --d2h-dark-file-header-bg-color: #272823;
   --d2h-dark-file-header-border-color: #3f4136;
 
   --d2h-dark-empty-placeholder-bg-color: #494b40;