body {
    background: #111;
    color: #fff;
    font-family: monospace;
    text-align: center;
    padding: 20px;
}
button {
    margin: 10px;
    padding: 10px 20px;
    background: #00ff88;
    border: none;
    color: black;
    font-weight: bold;
    border-radius: 8px;
    cursor: pointer;
}
.device {
    background: #222;
    margin: 10px auto;
    padding: 15px;
    width: 300px;
    border-radius: 10px;
}