.popup {
    display: none; /* Hidden by default */
    position: fixed;
    z-index: 1;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    overflow: auto;
    background-color: rgba(0,0,0,0.4);
}

.popup-content {
    background-color: #fefefe;
    margin: 10% auto;
    padding: 20px;
    border: 1px solid #888;
    width: 90%; /* 90% of the viewport width for mobile */
    max-width: 480px; /* Limit width for larger devices */
    box-sizing: border-box; /* Include padding and border in the element's total width and height */
}

/* Adjust popup size for very small devices */
@media (max-width: 480px) {
    .popup-content {
        width: 95%; /* More padding for very small devices */
        padding: 15px; /* Reduce padding on small devices */
        max-width: none; /* Remove max-width for tiny screens */
    }
}

.close-btn {
    color: #aaa;
    float: right;
    font-size: 28px;
    font-weight: bold;
}

    .close-btn:hover,
    .close-btn:focus {
        color: black;
        text-decoration: none;
        cursor: pointer;
    }