From Wikirhyme
<style type="text/css">
/*
Notes:
-You must log as admin to edit this page
-Whatever you enter in this page will be added to the html in the header after the standard style sheet, so you can override styles.
-if you want your code to look nice on this page, put a space at the beginning of each line
-This is the default style sheet that you can override : http://editthis.info/wiki/skins/monobook/main.css
For example uncomment this next section to turn all the text green:
*/
/*
body {
color: green;
}
*/
</style>
<script type="text/javascript">
//Feel free to add your javascript code here.
</script>