diff --git a/options.xhtml b/options.xhtml
index d0559f520..605db83a4 100644
--- a/options.xhtml
+++ b/options.xhtml
@@ -133,10 +133,11 @@ boolean</p>
  </span>
 </dt>
 <dd>
-<p>Color in which events in this calendar are displayed.</p>
+<p>Color in which events in this calendar are displayed.
+For instance ‘light green’ or an RGB color ‘#ff0000’</p>
 
 <p><span class="emphasis"><em>Type:</em></span>
-null or one of “black”, “white”, “brown”, “yellow”, “dark gray”, “dark green”, “dark blue”, “light gray”, “light green”, “light blue”, “dark magenta”, “dark cyan”, “dark red”, “light magenta”, “light cyan”, “light red”</p>
+null or string</p>
 
 <p><span class="emphasis"><em>Default:</em></span>
 <code class="literal">null</code></p>
@@ -1245,10 +1246,11 @@ null or (list of string)</p>
  </span>
 </dt>
 <dd>
-<p>Color in which events in this calendar are displayed.</p>
+<p>Color in which events in this calendar are displayed.
+For instance ‘light green’ or an RGB color ‘#ff0000’</p>
 
 <p><span class="emphasis"><em>Type:</em></span>
-null or one of “black”, “white”, “brown”, “yellow”, “dark gray”, “dark green”, “dark blue”, “light gray”, “light green”, “light blue”, “dark magenta”, “dark cyan”, “dark red”, “light magenta”, “light cyan”, “light red”</p>
+null or string</p>
 
 <p><span class="emphasis"><em>Default:</em></span>
 <code class="literal">null</code></p>