body{
    margin:0;
    font-family:Arial,Helvetica,sans-serif;
    background:#111;
    color:#eee;
    display:flex;
    justify-content:center;
    align-items:center;
    height:100vh;
}
.card{
    max-width:600px;
    padding:2rem;
    text-align:center;
    background:#1b1b1b;
    border-radius:12px;
    box-shadow:0 0 20px rgba(0,0,0,.4);
}
h1{color:#4CAF50;}
a{color:#6ab7ff;text-decoration:none;}
a:hover{text-decoration:underline;}