.countdown-clock {
  font-size: 22px;
  text-align: center;
}

.countdown-clock .years,
 .countdown-clock .months,
 .countdown-clock .days,
 .countdown-clock .hours,
 .countdown-clock .minutes,
 .countdown-clock .seconds {
  font-size: 33px;
  margin-left: 5px;
  display: inline-block;
  background-color:#F44336;
  color:#fff;
  border-radius:5px;
  padding:10px;
}

.countdown-clock span:first-of-type { margin-left: 0; }