body{font-family:system-ui;max-width:600px;margin:40px auto;padding:20px;color:#333}
nav{padding:12px 0;border-bottom:1px solid #eee;margin-bottom:30px}
nav a{margin-right:16px;color:#666;text-decoration:none}
nav a:hover{color:#000}
h1{color:#222}
button{padding:10px 20px;font-size:16px;background:#4a90e2;color:white;border:0;border-radius:6px;cursor:pointer}