diff --git a/css.html b/css.html
index 8018c4ff57..d34b487d8c 100644
--- a/css.html
+++ b/css.html
@@ -1777,6 +1777,7 @@ For example, <code>&lt;section&gt;</code> should be wrapped as inline.
     <div class="bs-callout bs-callout-warning">
       <h4>Cross-browser rendering</h4>
       <p>As a best practice, <strong>we highly recommend using the <code>&lt;button&gt;</code> element whenever possible</strong> to ensure matching cross-browser rendering.</p>
+      <p>Among other things, there's <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=697451">a Firefox bug</a> that prevents us from setting the <code>line-height</code> of <code>&lt;input&gt;</code>-based buttons, causing them to not exactly match the height of other buttons on Firefox.</p>
     </div>
 
   </div>