Separate high contrast theme (#7213)

app/javascript/styles/mastodon/compact_header.scss

@@ -2,7 +2,7 @@
   h1 {
     font-size: 24px;
     line-height: 28px;
-    color: $primary-text-color;
+    color: $darker-text-color;
     font-weight: 500;
     margin-bottom: 20px;
     padding: 0 10px;
@@ -20,7 +20,7 @@
 
     small {
       font-weight: 400;
-      color: $darker-text-color;
+      color: $secondary-text-color;
     }
 
     img {