.countdown {
 
  display: -webkit-box;
  display: -ms-flexbox;
  display: flex;
  padding: 0;
  border: 1px solid black;
  align-items:baseline;
  justify-content: center;
}

.countdown .day, .countdown .hour, .countdown .min, .countdown .sec {
  padding: 4px;
  text-align: center;
}

.countdown .num {

  font-size: 16px;
}

.countdown .word {

  font-size: 12px;
 
}