Pattern Skin Css Cookbook Recipe: Center the page with a border

   * Set USERSTYLEURL = %PUBURLPATH%/%SYSTEMWEB%/PatternSkinCssCookbookCenterPageBorder/centerpageborder.css

<style type="text/css" media="all">
#patternScreen {
background-image:url("%PUBURLPATH%/%SYSTEMWEB%/PatternSkinCssCookbookCenterPageBorder/gradient_page.gif");
background-repeat:repeat-x;
}
#patternPageShadow {
background-image:url("%PUBURLPATH%/%SYSTEMWEB%/PatternSkin/striped_pageshadow.gif");
}
</style>

If you don't write this overloading style in a template and use an external .css file, you need to set the image to the absolute url:

<style type="text/css" media="all">
    #patternScreen {
        background-image:url("%ATTACHURLPATH%/gradient_page.gif");
        background-repeat:repeat-x;
    }
</style>

You can always write a <style> in a topic - all current browsers support this - but the page won't validate as valid XHTML.