html {
  height: 100%;
}

body {
  height: 100%;
  background: #000000; // 85D8CE
  background: #000000;
  background: linear-gradient(135deg, #000000, #000000);
  background: linear-gradient(135deg, #000000, #000000);
}

.digit {
  position: relative;
  float: left;
  width: 10vw;
  height: 15vw;
  background-color: #fff;
  border-radius: 1vw;
  text-align: center;
  font-family: Oswald, sans-serif;
  font-size: 11vw;
}

.base {
  display: block;
  position: absolute;
  top: 50%;
  left: 50%;
  -webkit-transform: translate(-50%, -50%);
          transform: translate(-50%, -50%);
  color: #333;
}

.flap {
  display: none;
  position: absolute;
  width: 100%;
  height: 50%;
  background-color: #fff;
  left: 0;
  top: 0;
  border-radius: 1vw 1vw 0 0;
  -webkit-transform-origin: 50% 100%;
          transform-origin: 50% 100%;
  -webkit-backface-visibility: hidden;
          backface-visibility: hidden;
  overflow: hidden;
}
.flap::before {
  content: attr(data-content);
  position: absolute;
  left: 50%;
}
.flap.front::before, .flap.under::before {
  top: 100%;
  -webkit-transform: translate(-50%, -50%);
          transform: translate(-50%, -50%);
}
.flap.back {
  -webkit-transform: rotateY(180deg);
          transform: rotateY(180deg);
}
.flap.back::before {
  top: 100%;
  -webkit-transform: translate(-50%, -50%) rotateZ(180deg);
          transform: translate(-50%, -50%) rotateZ(180deg);
}
.flap.over {
  z-index: 2;
}
.flap.under {
  z-index: 1;
}
.flap.front {
  -webkit-animation: flip-down-front 300ms ease-in both;
          animation: flip-down-front 300ms ease-in both;
}
.flap.back {
  -webkit-animation: flip-down-back 300ms ease-in both;
          animation: flip-down-back 300ms ease-in both;
}
.flap.under {
  -webkit-animation: fade-under 300ms ease-in both;
          animation: fade-under 300ms ease-in both;
}

@-webkit-keyframes flip-down-front {
  0% {
    -webkit-transform: rotateX(0deg);
            transform: rotateX(0deg);
    background-color: #fff;
    color: #333;
  }
  100% {
    -webkit-transform: rotateX(-180deg);
            transform: rotateX(-180deg);
    background-color: #a6a6a6;
    color: black;
  }
}

@keyframes flip-down-front {
  0% {
    -webkit-transform: rotateX(0deg);
            transform: rotateX(0deg);
    background-color: #fff;
    color: #333;
  }
  100% {
    -webkit-transform: rotateX(-180deg);
            transform: rotateX(-180deg);
    background-color: #a6a6a6;
    color: black;
  }
}
@-webkit-keyframes flip-down-back {
  0% {
    -webkit-transform: rotateY(180deg) rotateX(0deg);
            transform: rotateY(180deg) rotateX(0deg);
    background-color: #a6a6a6;
    color: black;
  }
  100% {
    -webkit-transform: rotateY(180deg) rotateX(180deg);
            transform: rotateY(180deg) rotateX(180deg);
    background-color: #fff;
    color: #333;
  }
}
@keyframes flip-down-back {
  0% {
    -webkit-transform: rotateY(180deg) rotateX(0deg);
            transform: rotateY(180deg) rotateX(0deg);
    background-color: #a6a6a6;
    color: black;
  }
  100% {
    -webkit-transform: rotateY(180deg) rotateX(180deg);
            transform: rotateY(180deg) rotateX(180deg);
    background-color: #fff;
    color: #333;
  }
}
@-webkit-keyframes fade-under {
  0% {
    background-color: #a6a6a6;
    color: black;
  }
  100% {
    background-color: #fff;
    color: #333;
  }
}
@keyframes fade-under {
  0% {
    background-color: #a6a6a6;
    color: black;
  }
  100% {
    background-color: #fff;
    color: #333;		
  }
}
.clock {
  position: absolute;
  width: 70vw;
  top: 50%;
  left: 15vw;
  -webkit-transform: translateY(-50%);
          transform: translateY(-50%);
  -webkit-perspective: 100vw;
          perspective: 100vw;
  -webkit-perspective-origin: 50% 50%;
          perspective-origin: 50% 50%;
}
.clock .digit {
  margin-right: 1vw;
}
.clock .digit:nth-child(2n+2) {
  margin-right: 3.5vw;
}
.clock .digit:last-child {
  margin-right: 0;
}