.overlay {
    width: 100%;
    height: 100%;
    position: absolute;
    top: 0;
    left: 0;
    opacity: 0.9;
    animation: timerAnimation 15s linear infinite;
    transition-duration: 15s;
    border-radius: 5px;
}

@keyframes timerAnimation {
    0% {
        box-shadow: 0 0 10px rgba(255, 215, 0, 0.8);
    }
    50% {
        box-shadow: 0 0 20px rgba(255, 215, 0, 1);
    }
    100% {
        box-shadow: 0 0 10px rgba(255, 215, 0, 0.8);
    }
}