One of the most common issues in Drupal is admin page themeing, below pages theme of being some complicated, we have found the best solutions for that, so don't worry about Drupal admin page themeing
Here is the code
Add below code in your template.php file
function your_theme_admin_block_content($variables) {
$content = $variables['content'];
$output = '';
if (!empty($content)) {
$class = 'admin-lists';
if ($compact = system_admin_compact_mode()) {
$class .= ' compact';
}
$output .= '<div class="' . $class . '">';
foreach ($content as $item) {
$output .= '<div class="admin-extra"><div class="insidewrps">';
$output .= l($item['title'], $item['href'], $item['localized_options']);
if (!$compact && isset($item['description'])) {
$output .= '<span>' . filter_xss_admin($item['description']) . '</span>';
}
$output .= '</div></div>';
}
$output .= '</div>';
}
return $output;
}After adding the above code in your template.php file clear your drupal cache and check again, the above code for admin/structure, admin/config like pages