body{margin:0;padding:0;font-family:Segoe UI,Tahoma,Geneva,Verdana,sans-serif;background:#f0f4f8;color:#333}.app-container{max-width:600px;margin:50px auto;background:#fff;padding:30px;border-radius:10px;box-shadow:0 4px 12px #0000001a}h1,h2{text-align:center;margin-bottom:20px}.question{font-size:1.2em;margin-bottom:20px}.option{display:block;width:100%;padding:12px;margin:8px 0;border:2px solid transparent;border-radius:6px;background:#e7ecf0;cursor:pointer;text-align:left;transition:background .3s,border .3s}.option:hover{background:#d6dde5}.option.selected{background:#90caf9;border:2px solid #42a5f5}.nav-buttons{display:flex;justify-content:space-between;margin-top:20px}.nav-buttons button{padding:10px 20px;border:none;background:#42a5f5;color:#fff;border-radius:6px;cursor:pointer;font-size:1em;transition:background .3s}.nav-buttons button:hover{background:#1e88e5}.nav-buttons button:disabled{background:#a0c4e3;cursor:not-allowed}.restart-button{display:block;margin:20px auto;padding:10px 20px;border:none;background:#42a5f5;color:#fff;border-radius:6px;cursor:pointer;font-size:1em;transition:background .3s}.restart-button:hover{background:#1e88e5}.score{font-size:1.4em;text-align:center;margin:20px 0}