phacil-framework/system/ecompress/cssMin.php

<?php
/**
 * Copyright © 2024 ExacTI Technology Solutions. All rights reserved.
 * GPLv3 General License.
 * https://exacti.com.br
 * Phacil PHP Framework - https://github.com/exacti/phacil-framework
 */

namespace Phacil\Framework\ECompress;

/**
 * @api
 * @since 1.0.0
 * @package Phacil\Framework\ECompress
 */
class cssMin {
    /**
     * @param string $css 
     * @return string|null 
     */
    public function minify($css)
    {
        $css = preg_replace('!/\*[^*]*\*+([^/][^*]*\*+)*/!', '', $css);
        $css = preg_replace('/\/\*((?!\*\/).)*\*\//', '', $css); // negative look ahead
        $css = preg_replace('/\s{2,}/', ' ', $css);
        $css = preg_replace('/\s*([:;{}])\s*/', '$1', $css);
        $css = preg_replace('/;}/', '}', $css);

        return $css;
    }
}