body {
    font-family: Arial, sans-serif;
    text-align: center;
    padding: 40px;
    margin-bottom: 200px;
}
input {
    padding: 10px;
    font-size: 16px;
    margin: 10px;
}
button {
    padding: 10px 20px;
    font-size: 16px;
}
.ad-popup {
    position: fixed;
    bottom: 0;
    left: 0;
    width: 100%;
    background: #fff;
    z-index: 999;
    text-align: center;
    padding: 10px;
    box-shadow: 0 -2px 5px rgba(0,0,0,0.1);
}
#adPopup img {
    width: 100%;
    max-width: 300px;
}
#countdown {
    font-size: 18px;
    color: red;
    margin-top: 8px;
}