diff --git a/assets/stylesheets/pages/_mdn.scss b/assets/stylesheets/pages/_mdn.scss
index 10e144f3..a78b8b7c 100644
--- a/assets/stylesheets/pages/_mdn.scss
+++ b/assets/stylesheets/pages/_mdn.scss
@@ -107,7 +107,7 @@
 
   code > strong { font-weight: normal; }
 
-  // Compatibility tablees
+  // Compatibility tables
 
   .bc-github-link {
     float: right;
@@ -115,6 +115,7 @@
   }
 
   .bc-supports-yes, .bc-supports-yes + dd, .bc-supports-yes + dd + dd { background: var(--noteGreenBackground); }
+  .bc-supports-unknown, .bc-supports-unknown + dd, .bc-supports-unknown + dd + dd { background: var(--noteBackground); }
   .bc-supports-partial, .bc-supports-partial + dd, .bc-supports-partial + dd + dd { background: var(--noteOrangeBackground); }
   .bc-supports-no, .bc-supports-no + dd, .bc-supports-no + dd + dd { background: var(--noteRedBackground); }
 
diff --git a/lib/docs/filters/mdn/compat_tables.rb b/lib/docs/filters/mdn/compat_tables.rb
index 8f81b488..bb243f54 100644
--- a/lib/docs/filters/mdn/compat_tables.rb
+++ b/lib/docs/filters/mdn/compat_tables.rb
@@ -163,15 +163,14 @@ module Docs
 
           version_added.map! do |version|
             if version == true
-              version = 'Yes'
+              'Yes'
             elsif version == false
-              version = 'No'
+              'No'
             elsif version.is_a?(String)
+              version
             else
-              version = '?'
+              '?'
             end
-
-            version
           end
 
           if version_removed[0]
@@ -179,6 +178,8 @@ module Docs
           else
             if version_added[0] == 'No'
               format_string = "<td class=bc-supports-no>"
+            elsif version_added[0] == '?'
+              format_string = "<td class=bc-supports-unknown>"
             else
               format_string = "<td class=bc-supports-yes>"
             end
@@ -201,7 +202,7 @@ module Docs
           end
 
         else
-          format_string = "<td class=bc-supports-no><div>?</div></td>"
+          format_string = "<td class=bc-supports-unknown><div>?</div></td>"
         end
 
         entry.add_child(format_string)