DEV: Add simple digest for core stylesheets

And move fonts + category_backgrounds to color definitions stylesheet.
This will let us use the same core + plugin stylesheets in multisite.

lib/stylesheet/compiler.rb

@@ -29,9 +29,6 @@ module Stylesheet
         file += File.read path
 
         case asset.to_s
-        when "desktop", "mobile"
-          file += importer.category_backgrounds
-          file += importer.font
         when "embed", "publish"
           file += importer.font
         when "wizard"
@@ -39,6 +36,8 @@ module Stylesheet
         when Stylesheet::Manager::COLOR_SCHEME_STYLESHEET
           file += importer.import_color_definitions
           file += importer.import_wcag_overrides
+          file += importer.category_backgrounds
+          file += importer.font
         end
       end
 

lib/stylesheet/manager/builder.rb

@@ -137,6 +137,10 @@ class Stylesheet::Manager::Builder
     !!(@target.to_s =~ Stylesheet::Manager::THEME_REGEX)
   end
 
+  def is_color_scheme?
+    !!(@target.to_s == Stylesheet::Manager::COLOR_SCHEME_STYLESHEET)
+  end
+
   def scheme_slug
     Slug.for(ActiveSupport::Inflector.transliterate(@color_scheme.name), 'scheme')
   end
@@ -146,8 +150,10 @@ class Stylesheet::Manager::Builder
     @digest ||= begin
       if is_theme?
         theme_digest
-      else
+      elsif is_color_scheme?
         color_scheme_digest
+      else
+        default_digest
       end
     end
   end
@@ -171,7 +177,7 @@ class Stylesheet::Manager::Builder
   end
 
   def theme_digest
-    Digest::SHA1.hexdigest(scss_digest.to_s + color_scheme_digest.to_s + settings_digest + plugins_digest + uploads_digest)
+    Digest::SHA1.hexdigest(scss_digest.to_s + color_scheme_digest.to_s + settings_digest + uploads_digest)
   end
 
   # this protects us from situations where new versions of a plugin removed a file
@@ -218,6 +224,10 @@ class Stylesheet::Manager::Builder
     Digest::SHA1.hexdigest(sha1s.sort!.join("\n"))
   end
 
+  def default_digest
+    Digest::SHA1.hexdigest "default-#{Stylesheet::Manager.last_file_updated}-#{plugins_digest}"
+  end
+
   def color_scheme_digest
     cs = @color_scheme || theme&.color_scheme