body{margin:auto;background-color:#f4f4f9;color:#333}.app-container{display:flex;justify-content:center;align-items:center;height:100vh;background:linear-gradient(145deg,#e6e6e6,#fff);opacity:1;transition:background .25s ease-in-out,opacity .25s ease-in-out}h1{margin-bottom:1rem;color:#4a90e2}.input-container{margin-bottom:1rem}input{margin-left:1.5rem;text-align:center;padding:.5rem;font-size:1rem;border:1px solid #ccc;border-radius:8px;width:70%}button{padding:.5rem 1rem;font-size:1rem;color:#fff;background-color:#4a90e2;border:none;border-radius:8px;cursor:pointer;margin:auto;transition:background-color .3s}button:hover{background-color:#357abd}.qr-output{margin:1rem;border-radius:5px}.qr-image{height:auto;border:1px solid #ccc;border-radius:12px;padding:.5rem;background:#fff}.nightModeButton{position:absolute;top:1rem;right:1rem;padding:.5rem 1rem;font-size:1rem;color:#fff;background-color:#4a90e2;border:none;border-radius:8px;cursor:pointer;transition:background-color .3s}.app-container.night-mode{background:#333}