Оригинальные часы

let _timeElement10Digits = Array.from(Array(10)).map((n, i) => i);
let _timeElement6Digits = _timeElement10Digits.slice(0, 6);
let _timeElement3Digits = _timeElement10Digits.slice(0, 3);
let _timeElementStructure = [
        [ _timeElement3Digits, _timeElement10Digits ],
        [ _timeElement6Digits, _timeElement10Digits ],
        [ _timeElement6Digits, _timeElement10Digits ]
    ];

let clock = document.createElement('div');
clock.id = 'clock';
document.body.appendChild(clock);
let digitGroups = [];
requestAnimationFrame(update);

_timeElementStructure.forEach(digits => {
    let digitGroup = document.createElement('div');
    digitGroup.classList.add('digit-group');
    clock.appendChild(digitGroup);
    digitGroups.push(digitGroup);
    digits.forEach(digitList => {
        let digit = document.createElement('div');
        digit.classList.add('digit');
        digitList.forEach(n => {
            let ele = document.createElement('div');
            ele.classList.add('digit-number');
            ele.innerText = n;
            digit.appendChild(ele);
        });
        digitGroup.appendChild(digit);
    });
});

function update() {
    requestAnimationFrame(update);
    let date = new Date();
    let time = [ date.getHours(), date.getMinutes(), date.getSeconds() ]
        .map(n => `0${n}`.slice(-2).split('').map(e => +e))
        .reduce((p, n) => p.concat(n), []);
    time.forEach((n, i) => {
        let digit = digitGroups[Math.floor(i * 0.5)].children[i % 2].children;
        Array.from(digit).forEach((e, i2) => e.classList[i2 === n ? 'add' : 'remove']('highlight'));
    });
}

@import url("https://fonts.googleapis.com/css?family=Old+Standard+TT");
html,
body {
  height: 100%;
  font-family: 'Old Standard TT', serif;
  background-color: #1f1f1f;
  margin: 0;
  font-size: 0;
  color: white;
  text-align: center;
  overflow: hidden;
  background-image: url(../img/bg.jpg);
  -webkit-background-size: cover;
  background-size: cover;
  background-repeat: no-repeat;
  background-position: center bottom;
}

#clock {
  font-size: 24px;
  width: 350px;
  height: 350px;
  position: absolute;
  left: 50%;
  top: 50%;
  margin-left: -175px;
  margin-top: -175px;
}

.digit-group {
  display: inline-block;
  height: 350px;
}
.digit-group:not(:last-child):after {
  content: ':';
  font-size: 72px;
}

.digit {
  display: inline-block;
  width: 50px;
  height: 350px;
}
.digit .digit-number {
  color: rgba(255, 255, 255, 0.1);
  -webkit-transform: rotate(-90deg);
          transform: rotate(-90deg);
  -webkit-transition: font-size 200ms, color 150ms, -webkit-transform 350ms;
  transition: font-size 200ms, color 150ms, -webkit-transform 350ms;
  transition: font-size 200ms, transform 350ms, color 150ms;
  transition: font-size 200ms, transform 350ms, color 150ms, -webkit-transform 350ms;
}
.digit .digit-number.highlight {
  color: inherit;
  font-size: 72px;
  -webkit-transform: rotate(0deg);
          transform: rotate(0deg);
}