diff --git a/app/helpers/theme_helper.rb b/app/helpers/theme_helper.rb
index d15259851c0..fab899a5332 100644
--- a/app/helpers/theme_helper.rb
+++ b/app/helpers/theme_helper.rb
@@ -3,8 +3,10 @@
 module ThemeHelper
   def theme_style_tags(theme)
     if theme == 'system'
-      stylesheet_pack_tag('mastodon-light', media: 'not all and (prefers-color-scheme: dark)', crossorigin: 'anonymous') +
-        stylesheet_pack_tag('default', media: '(prefers-color-scheme: dark)', crossorigin: 'anonymous')
+      ''.html_safe.tap do |tags|
+        tags << stylesheet_pack_tag('mastodon-light', media: 'not all and (prefers-color-scheme: dark)', crossorigin: 'anonymous')
+        tags << stylesheet_pack_tag('default', media: '(prefers-color-scheme: dark)', crossorigin: 'anonymous')
+      end
     else
       stylesheet_pack_tag theme, media: 'all', crossorigin: 'anonymous'
     end
@@ -12,8 +14,10 @@ module ThemeHelper
 
   def theme_color_tags(theme)
     if theme == 'system'
-      tag.meta(name: 'theme-color', content: Themes::THEME_COLORS[:dark], media: '(prefers-color-scheme: dark)') +
-        tag.meta(name: 'theme-color', content: Themes::THEME_COLORS[:light], media: '(prefers-color-scheme: light)')
+      ''.html_safe.tap do |tags|
+        tags << tag.meta(name: 'theme-color', content: Themes::THEME_COLORS[:dark], media: '(prefers-color-scheme: dark)')
+        tags << tag.meta(name: 'theme-color', content: Themes::THEME_COLORS[:light], media: '(prefers-color-scheme: light)')
+      end
     else
       tag.meta name: 'theme-color', content: theme_color_for(theme)
     end