*{margin:0;padding:0;box-sizing:border-box}html,body{width:100%;height:100%;font-family:Segoe UI,system-ui,-apple-system,BlinkMacSystemFont,sans-serif;background:linear-gradient(135deg,#667eea,#764ba2);overflow:hidden}body{display:flex;align-items:center;justify-content:center}#app{width:100%;height:100%}