#countdown {
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
}

.countdown-item {
    font-size: 20px;
    border-radius: 50%;
    text-align: center;
    width:100px;
    height: 100px;
    line-height: 100px;
    position: relative;
    opacity: 0;
    margin: 5px;
}

.countdown-item.show {
    animation: fadein 2s forwards;
}

.countdown-item::before {
    position: absolute;
    content: ' ';
    width: 100px;
    height: 100px;
    border-radius: 50%;
    background-color: #fff;
    left: 0;
    top: 0;
    opacity: .1;
}

.countdown-item.days {
    animation-delay: 1s;
}

.countdown-item.hours {
    animation-delay: 1.5s;
}

.countdown-item.minutes {
    animation-delay: 2s;
}

.countdown-item.seconds {
    animation-delay: 2.5s;
}

.countdown-item.days::after {
    content: attr(data-days);
}

.countdown-item.hours::after {
    content: attr(data-hours);
}

.countdown-item.minutes::after {
    content: attr(data-minutes);
}

.countdown-item.seconds::after {
    content: attr(data-seconds);
}

@keyframes fadein {
    from { opacity: 0; }
    to { opacity: 1; }
}