body {
    font-family: Arial, sans-serif;
    background: #0d0d0d;
    color: #fff;
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    margin: 0;
}
.box {
    background: #1a1a1a;
    padding: 30px;
    border-radius: 12px;
    text-align: center;
    box-shadow: 0 0 15px rgba(0,0,0,.4);
}
button {
    margin-top: 20px;
    background: #22cc26;
    border: none;
    padding: 10px 20px;
    border-radius: 6px;
    cursor: pointer;
    font-size: 16px;
    color: #000;
    font-weight: bold;
}