If the theme is not custom, you should first create a Child Theme, otherwise any changes made to original theme files will be overwritten once the theme updates.
You need the basic example of a child theme in the link (above), then a copy of this file from the theme, into the child theme.
Then you can modify this file (from within the child theme).
This could be a possible change for your <div>;
<?php get_header(); ?>
<?php global $sb_primary,$sb_secondary ;$sb_primary = 'default';$sb_secondary = 'secondary'; ?>
<style type='text/css'>
.post ol {list-style-position:outside;}
.post ul li, .post ol ul li {overflow:visible;}
</style>
<?php if (theme_get_option('top_sidebar_search') && theme_get_option('top_sidebar_wide_search')) {get_sidebar('top');} ?>
<?php tt_get_header_layout(); ?>
<?php if (theme_get_option('top_sidebar_search') && !theme_get_option('top_sidebar_wide_search')) {get_sidebar('top');} ?>
<?php
if(have_posts()) {
echo '<div class="search_wrapper">';
theme_post_wrapper(
array('content' => '<h4 class="box-title">' . sprintf( __( 'Search Results for: %s', THEME_NS ),
'<span>' . get_search_query() . '</span>' ) . '</h4>'
)
);
/* Display navigation to next/previous pages when applicable */
if (theme_get_option('theme_top_posts_navigation')) {
theme_page_navigation();
}
/* Start the Loop */
while (have_posts()) {
the_post();
get_template_part('content', get_post_format());
}
/* Display navigation to next/previous pages when applicable */
if (theme_get_option('theme_bottom_posts_navigation')) {
theme_page_navigation();
}
echo '</div>';
} else { ?>
<div style="width: 790px; height: 365px; margin: 5px; overflow: auto;">
<?php ob_start();
$title_search = __('Sorry but I can\'t find the page you\'re looking for...', 'THEME_NS');?>
<p><?php _e('Let me help you find what you came here for:', 'THEME_NS'); ?></p>
<?php
$s = preg_replace("/(.*)-(html|htm|php|asp|aspx)$/","$1",$wp_query->query_vars['name']);
$posts = query_posts('post_type=post&name='.$s);
$s = str_replace("-"," ",$s);
if (count($posts) == 0) {
$posts = query_posts('post_type=post&s='.$s);
}
if (count($posts) > 0) { ?>
<ol><li>
<p><?php _e('Were you looking for <strong>one of the following</strong> posts?', 'THEME_NS'); ?></p>
<ul>
<?php foreach ($posts as $post) {
echo '<li><a href="'.get_permalink($post->ID).'">'.$post->post_title.'</a></li>';
}
echo "</ul>"; ?>
<p><?php _e('If not, don\'t worry, I\'ve got a few more tips for you to find it:', 'THEME_NS'); ?></p></li>
<?php } else { ?>
<p><?php _e('<strong>Don\'t worry though!</strong> I\'ve got a few tips for you to find it:', 'THEME_NS'); ?></p>
<ol>
<?php }
?>
<li><p>
<?php _e('<strong>Search</strong> for it:', 'THEME_NS'); ?>
<form style="display:inline;" action="<?php bloginfo('siteurl');?>">
<input type="text" value="<?php echo esc_attr($s); ?>" id="s" name="s"/> <input type="submit" value="Search"/>
</form></p>
</li>
<li><p>
<?php _e('<strong>If you typed in a URL...</strong> make sure the spelling, cApitALiZaTiOn, and punctuation are correct. Then try reloading the page.', 'THEME_NS'); ?></p>
</li>
<li><p>
<?php _e('<strong>Look</strong> for it in the ', 'THEME_NS'); ?><a href="<?php bloginfo('siteurl');?>/sitemap/"><?php _e('sitemap', 'THEME_NS'); ?></a>.
</p>
</li>
<li><p>
<?php _e('<strong>Start over again</strong> at my ', 'THEME_NS'); ?><a href="<?php bloginfo('siteurl');?>"><?php _e('homepage', 'THEME_NS'); ?></a><?php _e(' (and please contact me to say what went wrong, so I can fix it).', 'THEME_NS'); ?></p>
</li>
</ol>
<?php
theme_post_wrapper(
array(
'title' => $title_search,
'content' => ob_get_clean()
)
);
?></div>
<?php } ?>
<?php if (theme_get_option('bot_sidebar_search') && !theme_get_option('bot_sidebar_wide_search')) {get_sidebar('bottom');} ?>
<?php tt_get_footer_layout(); ?>
<?php if (theme_get_option('bot_sidebar_search') && theme_get_option('bot_sidebar_wide_search')) {get_sidebar('bottom');} ?>
<?php get_footer(); ?>
I've wrapped a <div class="search_wrapper"> around your search results, which encourages external or internal CSS use.