wp_enqueue_scripts hangs

I’m not sure you can use is_page() in the function.php (citation needed!). Instead of enqueuing the the style sheets, you could echo them in the header.php.

So, in the header.php you’d want…

<?php
if ( is_front_page() ) {
    echo '<link rel="stylesheet" type="text/css" href="' . get_template_directory_uri() . '/css/homepage.css">';
} else if ( is_page( 'corsi' ) ) {
    echo '<link rel="stylesheet" type="text/css" href="' . get_template_directory_uri() . '/css/corsi.css">';