Update the model's transparent background color for the dark theme.

lib/decentralised_book_index_web/components/core_components.ex

@@ -50,7 +50,7 @@ defmodule DecentralisedBookIndexWeb.CoreComponents do
       data-cancel={JS.exec(@on_cancel, "phx-remove")}
       class="relative z-50 hidden"
     >
-      <div id={"#{@id}-bg"} class="bg-zinc-50/90 fixed inset-0 transition-opacity" aria-hidden="true" />
+      <div id={"#{@id}-bg"} class="bg-zinc-50/90 dark:bg-gray-900/90 fixed inset-0 transition-opacity" aria-hidden="true" />
       <div
         class="fixed inset-0 overflow-y-auto"
         aria-labelledby={"#{@id}-title"}