diff --git a/app/javascript/styles/mastodon/rich_text.scss b/app/javascript/styles/mastodon/rich_text.scss
index 0d70eced55..f5d4cde6c6 100644
--- a/app/javascript/styles/mastodon/rich_text.scss
+++ b/app/javascript/styles/mastodon/rich_text.scss
@@ -81,6 +81,10 @@
   ol {
     list-style-type: decimal;
   }
+
+  sup {
+    vertical-align: super;
+  }
 }
 
 .reply-indicator__content {
diff --git a/app/lib/text_formatter.rb b/app/lib/text_formatter.rb
index 607583ab2f..91c0ac1273 100644
--- a/app/lib/text_formatter.rb
+++ b/app/lib/text_formatter.rb
@@ -171,9 +171,11 @@ class TextFormatter
     @markdown ||= Redcarpet::Markdown.new(@htmlobj,
         autolink: false,
         tables: false,
-        underline: true,
         disable_indented_code_blocks: false,
         fenced_code_blocks: true,
+        strikethrough: true,
+        superscript: true,
+        underline: true,
         highlight: false
       )
     @markdown.render(html)
@@ -196,6 +198,10 @@ class TextFormatter
       "<p>#{text}</p>"
     end
 
+    def underline(text)
+      text.include?(':') ? nil : '<u>' + text + '</u>'
+    end
+
     private
 
     def process_program_code(code)