Is it advisable to develop a custom CMS in PHP, or is it better to use an existing open-source CMS and customize it?

It is generally advisable to use an existing open-source CMS and customize it to fit your needs rather than developing a custom CMS from scratch in PHP. This approach can save time and effort, as open-source CMS platforms like WordPress, Joomla, and Drupal already have a wide range of features and plugins available for customization. Additionally, using an established CMS can provide better security, community support, and regular updates.

// Example of customizing a WordPress theme in PHP

// Add custom CSS styles
function custom_theme_styles() {
    wp_enqueue_style( 'custom-style', get_template_directory_uri() . '/css/custom-style.css' );
}
add_action( 'wp_enqueue_scripts', 'custom_theme_styles' );

// Add custom JavaScript scripts
function custom_theme_scripts() {
    wp_enqueue_script( 'custom-script', get_template_directory_uri() . '/js/custom-script.js', array('jquery'), '', true );
}
add_action( 'wp_enqueue_scripts', 'custom_theme_scripts' );

// Add custom functionality
function custom_theme_function() {
    // Add your custom PHP code here
}
add_action( 'init', 'custom_theme_function' );