body{
    background:#1e1e1e;
    display:flex;
    justify-content:center;
    align-items:center;
    height:100vh;
    font-family:Arial;
}

.ventana{
    background:#2d2d2d;
    padding:30px;
    border-radius:12px;
    box-shadow:0 0 20px black;
    text-align:center;
}

input{
    display:block;
    margin:10px auto;
    padding:8px;
    width:120px;
}

button{
    padding:10px 20px;
    cursor:pointer;
}