CODE EXAMPLE FOR PHP

wp enqueue styles

/** 
 *   Enqueue your theme styles and scripts in functions.php
 *   use time() instead of a proper versioning to avoid caching when developing
 */
function my_theme_enqueue_scripts() {
    wp_enqueue_style( 'default-style', get_stylesheet_uri(), [], '1.0.0', 'all' ); //default styles.css
    wp_enqueue_style( 'main-style', get_stylesheet_directory_uri() . '/assets/css/main.min.css', [], time(), 'all' );
    wp_enqueue_script( 'main-script', get_stylesheet_directory_uri() . '/assets/js/main.min.js', [], time(), false );
}
add_action( 'wp_enqueue_scripts', 'my_theme_enqueue_scripts' );