Use CSS tag inside PHP code

I’m not sure if you can add styles in filters.
I tested the below code in wp_head action and worked perfectly:

function show_outlet_msg(){
    $term = get_term( 40, 'product_cat' );
    $total_products=$term->count;
    if ($total_products>0){
        $html="<style> #txt_outlet_zero{ display: none; } </style>";
    } else {
        $html="<style> #txt_outlet_head{ display: none; } </style>";
    }
    echo $html;
}

add_action('wp_head','show_outlet_msg');