countdown.css

.countdown-container {
    background-image: url('');
    background-size: cover;
    background-repeat: no-repeat;
    margin: 20px 0px;
    background-position: center;
}

.countdown-container > #clockdiv .days,
.countdown-container > #clockdiv .hours,
.countdown-container > #clockdiv .minutes,
.countdown-container > #clockdiv .seconds {
    display: inline-block;
    line-height: 1;
    padding-top: 8px;
    background-color: #1e0576;
    font-size: 95px;
    text-align: center;
    width: 150px;
    color: #ffffff;
    font-weight: 600;
    padding-bottom: 8px;
    margin-bottom: 2px;
}
.countdown-header {
    text-align: center;
    padding-top: 25px;
    color: #fff;
    font-size: 45px;
    text-transform: uppercase;
    font-weight: 600;
    line-height: 1;
    text-shadow: 1px 3px 15px rgba(0,0,0,0.5);
}
#clockdiv {
    display: table;
    margin: 10px auto;
    min-height: 140px;
    opacity: 0;
    transition: opacity .5s;
}
#clockdiv > div {
    display: inline-block;
    margin-right: 5px;
}
.smalltext {
    color: #fff;
    text-transform: uppercase;
    font-size: 18px;
    font-weight: 600;
    text-shadow: 1px 1px 15px rgba(0,0,0,0.5);
}
.countdown-link {
    text-align: center;
    padding-bottom: 20px;
}
.countdown-link a {
    color: #fff !important;
    font-size: 18px;
    font-weight: 600;
    text-shadow: 1px 1px 15px rgba(0,0,0,0.5);
}
@media(max-width:767px){
    #clockdiv{
         min-height: unset;
    }
    .countdown-container > #clockdiv .days, .countdown-container > #clockdiv .hours, .countdown-container > #clockdiv .minutes, .countdown-container > #clockdiv .seconds{
        font-size: 50px;
        width: 100px;
    }
}
@media(max-width:470px){
    .countdown-container > #clockdiv .days, .countdown-container > #clockdiv .hours, .countdown-container > #clockdiv .minutes, .countdown-container > #clockdiv .seconds{
        font-size: 40px;
        width: 65px;
    }
    .countdown-link{
        padding: 0 20px 20px;
    }
    .smalltext{
        font-size:16px;
    }
}
@media(max-width:335px){
    .countdown-container > #clockdiv .days, .countdown-container > #clockdiv .hours, .countdown-container > #clockdiv .minutes, .countdown-container > #clockdiv .seconds{
        font-size: 30px;
        width: 50px;
    }
    .smalltext{
        font-size:12px;
    }
    .countdown-header {
        font-size: 40px;
    }
}

countdown.html

<div class="row">
    <div class="col-md-12">
        <div class="countdown-container">
            <div class="countdown-header">
                {{CmsWidgetOption:Header}}
            </div>
            <div id="clockdiv">
                <div>
                    <span class="days"></span>
                    <div class="smalltext">Days</div>
                </div>
                <div>
                    <span class="hours"></span>
                    <div class="smalltext">Hours</div>
                </div>
                <div>
                    <span class="minutes"></span>
                    <div class="smalltext">Minutes</div>
                </div>
                <div>
                    <span class="seconds"></span>
                    <div class="smalltext">Seconds</div>
                </div>
                
            </div>
            <div class="countdown-link">
                <a href="{{CmsWidgetOption:linkUrl}}">
                    {{CmsWidgetOption:linkText}}
                </a>
            </div>
        </div>
    </div>
</div>

countdown.js

    require(['modules/config.min'], function () {
        require(['lib/jquery-1.12.0.min', 'lib/moment.min'], function (jQuery, moment) {

            $(document).ready(function () {
                function getMomentTimeRemaining(endtime) {
                    var parsedEndTime = moment(endtime);
                    var currentTime = moment();
                    
                    var duration = moment.duration(parsedEndTime.diff(currentTime));
                    
                    var seconds = duration.seconds();
                    var minutes = duration.minutes();
                    var hours = duration.hours();
                    var days = duration.days();
                    
                    return {
                        'total': duration,
                        'days': days,
                        'hours': hours,
                        'minutes': minutes,
                        'seconds': seconds
                    };
                }
                
                function getTimeRemaining(endtime) {
                    var t = Date.parse(endtime) - Date.parse(new Date());
                    var seconds = Math.floor((t / 1000) % 60);
                    var minutes = Math.floor((t / 1000 / 60) % 60);
                    var hours = Math.floor((t / (1000 * 60 * 60)) % 24);
                    var days = Math.floor(t / (1000 * 60 * 60 * 24));
                    return {
                        'total': t,
                        'days': days,
                        'hours': hours,
                        'minutes': minutes,
                        'seconds': seconds
                    };
                }

                function initializeClock(id, endtime, callback) {
                    var clock = document.getElementById(id);
                    var daysSpan = clock.querySelector('.days');
                    var hoursSpan = clock.querySelector('.hours');
                    var minutesSpan = clock.querySelector('.minutes');
                    var secondsSpan = clock.querySelector('.seconds');

                    function updateClock() {
                        //var t = getTimeRemaining(endtime);
                        var t = getMomentTimeRemaining(endtime);

                        daysSpan.innerHTML = t.days;
                        hoursSpan.innerHTML = ('0' + t.hours).slice(-2);
                        minutesSpan.innerHTML = ('0' + t.minutes).slice(-2);
                        secondsSpan.innerHTML = ('0' + t.seconds).slice(-2);

                        if (t.total <= 0) {
                            clearInterval(timeinterval);
                            clock.style.display = 'none';
                        }

                        callback();
                    }

                    updateClock();
                    var timeinterval = setInterval(updateClock, 1000);
                }

                var deadline = '2017-11-01 08:00:00';
                //var timeInMinutes = 1;
                //var currentTime = Date.parse(new Date());
                //var deadline = new Date(currentTime + timeInMinutes * 60 * 1000);
                initializeClock('clockdiv', deadline, function () {
                    document.getElementById("clockdiv").style.opacity = "1";
                });
            });
        });
    });