body{margin:0;font-family:-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,Oxygen,Ubuntu,Cantarell,Open Sans,Helvetica Neue,sans-serif;display:flex;justify-content:center;align-items:center;min-height:100vh;background-color:#f5f5f5}.app{display:flex;flex-direction:column;align-items:center;padding:20px}.timer-container{display:flex;flex-direction:column;align-items:center;gap:20px}.timer{font-size:24px;font-weight:700;padding:10px 20px;border-radius:5px;background-color:#333;color:#fff}.game-over{position:fixed;top:0;left:0;width:100%;height:100%;background:rgba(0,0,0,.8);display:flex;flex-direction:column;align-items:center;justify-content:center;color:#fff;z-index:100}.game-over h2{font-size:3rem;margin-bottom:20px}.game-over button{padding:10px 20px;font-size:1.2rem;background-color:#fff;border:none;border-radius:5px;cursor:pointer}