How to enqueue the style using wp_enqueue_style()

I’m developing a theme. I added the codes (below) into the header.php. But I posted it into the theme repository, and it’s under review, and the reviewer informed me to enqueue the style with wp_enqueue_style()/wp_enqueue_script(). But can’t understand how to implement it with the function. I’ve seen the directed wp_enqueue_style();, but can’t understand how to put the whole bunch of codes with their conditions.

<style type="text/css">
<?php
// If the menu presents, then CSS loads

if ( has_nav_menu( 'secondary' ) ) {
?>
.sec-menu{
width: 100%;
background: #333;
height: 26px;
font-size:16px;
text-transform:uppercase;
}
<?php } ?>
<?php
if ( has_nav_menu( 'primary' ) ) {
?>
#access{
background-color: #333;
height: 26px;
}
<?php } ?>
<?php
if ( !has_nav_menu( 'primary' ) && !has_nav_menu( 'secondary' ) ) {
?>
.sec-menu,
#access{
border-bottom: 2px solid #333;
}
<?php } ?>
</style>

Anybody can help me here?