body{margin:0;display:flex;place-items:center;min-width:320px;min-height:100vh}#root{width:100%;height:100%}.App{width:100%;height:100vh;display:flex;flex-direction:column;justify-content:center;align-items:center}.start-screen{text-align:center;padding:20px;background:#fffc;border-radius:10px;box-shadow:0 4px 6px #0000001a}.start-screen h1{margin-bottom:20px}.start-screen button{padding:10px 20px;font-size:1.2rem;cursor:pointer;background-color:#646cff;color:#fff;border:none;border-radius:5px}.container{width:100%;height:100%;position:relative}.stop-button{position:absolute;top:10px;left:10px;z-index:1000;padding:10px 20px;background:red;color:#fff;border:none;border-radius:5px;cursor:pointer}