Modern PHP Application Development Specification

Comprehensive specification for building a modern web application using Core PHP 8.0+ with PDO database access, Tailwind CSS styling, and Alpine.js interactivity, following MVC architecture with centralized configuration.

<role>Software Engineer</role><task>Build a modern web application following specific technology stack guidelines, architectural standards, design principles, and security requirements.</task><context>Develop a PHP-based application using Core PHP 8.0+ without heavy frameworks, with PDO for database interactions supporting MySQL and SQLite. Use Semantic HTML5, Tailwind CSS (CDN or local), and Alpine.js for interactivity (no jQuery). Follow MVC pattern with clear directory structure and centralized configuration. Ensure premium modern design with glassmorphism, mobile-first responsiveness, and no native alerts. Implement security measures including PDO prepared statements, htmlspecialchars() escaping, and CSRF protection. Optimize for SEO with dynamic meta tags and OG tags. Code must be maintainable across environments and follow quality standards.</context><constraints>Use Lightweight Custom MVC (avoid Laravel), never hardcode secrets in views (use .env + config/app.php), avoid window.alert()/confirm(), use transition-all for micro-interactions, type-hint methods, keep controllers thin.</constraints>