agungshiro

<?php
                    $menu =  explode('<li ',substr((wp_list_pages("sort_order=asc&echo=0&depth=0&title_li=")),4));
                    $color = array('blue','orange','green');
                    $sub = 0;
                    $i = 0;
                    $id = array();
                    foreach ($menu as $key => $val) {
                        $match = $matches = 0;
                        if ($sub == 0){
                            $id[] = $key;
                            $pos = strpos($val,'<a');
                            $text = '<li><div class="'.$color[$i].'-left"></div><div class="'.$color[$i].'-mid">'.substr($val,$pos);
                            $text1 = str_replace('</a>','</a></div><div class="'.$color[$i].'-right"></div><div class="clear"></div>',$text);
                            $text2 = str_replace('<a','<a class="top" ',$text1);
                            echo $text2;
                        }else{
                            echo '<li '.$val;
                        }
                        if (preg_match_all("/(<ul>)/",$val,$match,PREG_PATTERN_ORDER)){
                            $sub = $sub + count($match[0]);
                        }else if (preg_match_all("/(<\/ul>)/",$val,$matches,PREG_PATTERN_ORDER)){
                            $sub = $sub - count($matches[0]);
                        };
                        $i++;
                        if($i==3){$i=0;};
                    }
                ?>

I use this code to modify only the first parent of list.
you can make another methods too.
I hope its solve your problem.