<?php
add_action('wp_enqueue_scripts', function() {
    wp_enqueue_style(
        'my-theme-custom',
        get_theme_file_uri('theme.css'),
        array(),
        filemtime(get_theme_file_path('theme.css'))
    );
});
add_action('after_setup_theme', function () {
    add_theme_support('custom-logo', [
        'height'      => 250,
        'width'       => 250,
        'flex-width'  => true,
        'flex-height' => true,
    ]);

    set_theme_mod('custom_logo', attachment_url_to_postid(
        get_theme_file_uri('assets/images/logo.png')
    ));
});