<?xml version="1.0"?>

<?xml-stylesheet href="chrome://global/skin" type="text/css"?>

<window xmlns:html="http://www.w3.org/1999/xhtml"
        xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">

<html:style>
hbox, vbox { background-color: white; }
hbox:-moz-locale-dir(ltr) { background-color: yellow; }
vbox:-moz-locale-dir(rtl) { background-color: green; }
</html:style>

<hbox id="hbox">
  <button label="One"/>
  <button label="Two"/>
  <button label="Three"/>
</hbox>
<vbox id="vbox">
  <button label="One"/>
  <button label="Two"/>
  <button label="Three"/>
</vbox>

</window>
