Generate CSS entrypoint for Custom Admin CSS

app/views/layouts/alchemy/admin.html.erb

@@ -12,6 +12,7 @@
     <meta name="turbo-cache-control" content="no-cache">
     <%= stylesheet_link_tag('alchemy/admin', media: 'screen', 'data-turbo-track' => true) %>
     <%= stylesheet_link_tag('alchemy/admin/print', media: 'print', 'data-turbo-track' => true) %>
+    <%= stylesheet_link_tag('alchemy/admin/custom', 'data-turbo-track' => true) %>
     <%= yield :stylesheets %>
     <script>
       // Global Alchemy JavaScript object.

lib/alchemy/upgrader/seven_point_three.rb

@@ -1,13 +1,39 @@
 # frozen_string_literal: true
 
 require "fileutils"
+require "thor"
 
 module Alchemy
   class Upgrader::SevenPointThree < Upgrader
-    def self.remove_admin_stylesheets
-      if File.exist? "vendor/assets/stylesheets/alchemy/admin/all.css"
-        log "Removing Alchemy admin stylesheets."
-        FileUtils.rm_f "vendor/assets/stylesheets/alchemy/admin/all.css"
+    include Thor::Base
+    include Thor::Actions
+
+    source_root Alchemy::Engine.root.join("lib/generators/alchemy/install/files")
+
+    class << self
+      def remove_admin_stylesheets
+        if File.exist? "vendor/assets/stylesheets/alchemy/admin/all.css"
+          log "Removing Alchemy admin stylesheets."
+          FileUtils.rm_f "vendor/assets/stylesheets/alchemy/admin/all.css"
+        end
+      end
+
+      def generate_custom_css_entrypoint
+        if File.exist? "app/assets/config/manifest.js"
+          log "Generating alchemy/admin/custom.css entrypoint file."
+          task.copy_file "custom.css", "app/assets/stylesheets/alchemy/admin/custom.css"
+          task.append_to_file "app/assets/config/manifest.js", "//= link alchemy/admin/custom.css\n"
+          todo(<<~TODO, "Custom styles have been moved to `app/assets/alchemy/admin/custom.css`")
+            Check the new `app/assets/alchemy/admin/custom.css` file for any custom styles you might
+            have added to the old `vendor/assets/stylesheets/alchemy/admin/all.css` file.
+          TODO
+        end
+      end
+
+      private
+
+      def task
+        @_task || new
       end
     end
   end

lib/generators/alchemy/install/files/custom.css

@@ -0,0 +1,4 @@
+/*
+ * Edit this file to add custom styles to the Alchemy admin interface.
+ * This file will be loaded after the default Alchemy admin stylesheets.
+ */

lib/generators/alchemy/install/install_generator.rb

@@ -65,6 +65,8 @@ def copy_yml_files
 
       def install_assets
         copy_file "all.js", app_vendor_assets_path.join("javascripts", "alchemy", "admin", "all.js")
+        copy_file "custom.css", app_assets_path.join("stylesheets/alchemy/admin/custom.css")
+        append_to_file Rails.root.join("app/assets/config/manifest.js"), "//= link alchemy/admin/custom.css\n"
       end
 
       def copy_demo_views

lib/tasks/alchemy/upgrade.rake

@@ -61,13 +61,19 @@ namespace :alchemy do
 
     namespace "7.3" do
       task "run" => [
-        "alchemy:upgrade:7.3:remove_admin_stylesheets"
+        "alchemy:upgrade:7.3:remove_admin_stylesheets",
+        "alchemy:upgrade:7.3:generate_custom_css_entrypoint"
       ]
 
       desc "Remove alchemy admin stylesheets"
       task remove_admin_stylesheets: [:environment] do
         Alchemy::Upgrader::SevenPointThree.remove_admin_stylesheets
       end
+
+      desc "Generate custom css entrypoint"
+      task generate_custom_css_entrypoint: [:environment] do
+        Alchemy::Upgrader::SevenPointThree.generate_custom_css_entrypoint
+      end
     end
   end
 end

spec/dummy/app/assets/config/manifest.js

@@ -4,3 +4,4 @@
 //= link_tree ../images
 //= link tinymce/langs/de.js
 //= link_tree ../builds
+//= link alchemy/admin/custom.css

spec/dummy/app/assets/stylesheets/alchemy/admin/custom.css

@@ -0,0 +1,4 @@
+/*
+ * Edit this file to add custom styles to the Alchemy admin interface.
+ * This file will be loaded after the default Alchemy admin stylesheets.
+ */