구조가 단순해서 간단히 레이아웃 만들어서 게시판에 적용하면 되겠네요
########## layout.html ########
<!--%import("css/default.css")-->
<div id="page"> <div id="top">
 <!--@if(!$layout_info->logo_image)--> <img src="./images/topimg.gif" />
 <!--@else--><img src="{$layout_info->logo_image}" /><!--@end-->
 </div> <div id="main">  {$content} </div></div>
############################

########## conf / info.xml #############
<?xml version="1.0" encoding="utf-8"?>
<layout version="0.1">
    <title xml:lang="ko"> simple Layout </title>
    <author email_address="" link="" date="">
        <name xml:lang="ko">  </name>
        <description xml:lang="ko">
            Just simple!
        </description>
    </author>
    <extra_vars>
        <var name="logo_image" type="image">
         <title xml:lang="ko">top image</title>
            <description xml:lang="ko">
                top image
            </description>
        </var>
    </extra_vars>
</layout>
##################################

######### css / default.css ############
@charset "utf-8";

body{
 font-family: "돋움", Dotum, "굴림", Gulim;
 font-size:0.8em;
 height:100%;
 text-align:center;
}

#page{
 width:800px;
 text-align:left;
 margin:0 auto;
}

#top{
 width:800px;
 height:100px;
}

#main{
 width: 800px;
}
########################