diff --git a/public/help/en/wiki_syntax_detailed_common_mark.html b/public/help/en/wiki_syntax_detailed_common_mark.html
index 087fa6f05..74c1dd2ef 100644
--- a/public/help/en/wiki_syntax_detailed_common_mark.html
+++ b/public/help/en/wiki_syntax_detailed_common_mark.html
@@ -356,6 +356,19 @@ It can be expanded by clicking a link.
 <tr><td align="center" colspan="2">bar</td></tr>
 </table>
 
+<p>The <strong>style</strong> attribute can be used in raw HTML to apply custom formatting. The following CSS properties are allowed:</p>
+<pre><code>
+  color background-color
+  width
+  height
+  padding padding-left padding-right padding-top padding-bottom
+  margin margin-left margin-right margin-top margin-bottom
+  border border-left border-right border-top border-bottom border-radius border-style border-collapse border-spacing
+  font font-style font-variant font-weight font-stretch font-size line-height font-family
+  text-align
+  float
+</code></pre>
+
 </body>
 </html>