css for menu and inserted search box

I have a child theme of simple market and I have inserted a search box at the end using the following code

add_filter(‘wp_nav_menu_items’,’add_search_box’, 10, 2);

function add_search_box($items, $args) {



$searchform = ob_get_contents();


$items .= ‘<li id=”menu-item-search”>’ . $searchform . ”;

return $items;


this works fine in that it is putting the search box there but I wanted it to go to the right of the menu bar. A general look through google for this seemed to indicate that

#menu-item-search {

float : right!important;


should work but it doesn’t make any difference?