style.css
* {
  font-family: 'Roboto Slab', serif;
  margin: 0;
  padding: 0;
}

body {
  -webkit-perspective: 500px;
     -moz-perspective: 500px;
       -o-perspective: 500px;
          perspective: 500px;
}

html, body {
  width: 100%;
  height: 100%;
  position: absolute;
}

header {
  width: 100%;
  text-align: center;
  box-sizing: border-box;
  & .buttons {
    position: absolute;
    text-align: center;
    width: 300px;
    margin-left: -150px;
    left: 50%;
  }
}

footer {
  box-sizing: border-box;
  position: absolute;
  width: 100%;
  text-align: center;
  color: #707070;

  & img {
    display: block;
    margin: 0 auto;
  }
}

& .section3d {
  position: absolute;
  top: 50%;
  left: 50%;
}

& section {
  position: absolute;
  top: 50%;
  left: 50%;
  -webkit-transition: -webkit-transform .5s;
     -moz-transition:    -moz-transform .5s;
       -o-transition:      -o-transform .5s;
          transition:         transform .5s;

  border-radius: 50%;
  background: #f0f0f0;
  text-align: center;

  & .header {
    font-size: 20px;
    color: #787878;
  }
}

& textarea {
  border: 1px solid #707070;
  border-radius: 5px;
  text-align: center;
  outline: none;
  resize: none;
  overflow: auto;
  -webkit-appearance: none;
     -moz-appearance: none;
      -ms-appearance: none;
       -o-appearance: none;
          appearance: none;

  &.empty {
    border: 1px dashed #707070;
  }
}

@openClose : cubic-bezier(0.6, -0.28, 0.735, 0.045);
@closeOpen : cubic-bezier(0.175, 0.885, 0.32, 1.275);

.front {
  &.hidden {
    -webkit-transform: rotateY(90deg);
       -moz-transform: rotateY(90deg);
        -ms-transform: rotateY(90deg);
         -o-transform: rotateY(90deg);
            transform: rotateY(90deg);
  }

  &.open-close {
    -webkit-transition-timing-function: @openClose;
       -moz-transition-timing-function: @openClose;
        -ms-transition-timing-function: @openClose;
         -o-transition-timing-function: @openClose;
            transition-timing-function: @openClose;
  }

  &.close-open {
    -webkit-transition-timing-function: @closeOpen;
       -moz-transition-timing-function: @closeOpen;
        -ms-transition-timing-function: @closeOpen;
         -o-transition-timing-function: @closeOpen;
            transition-timing-function: @closeOpen;
  }
}

.back {
  background:  #0072b8;
  &.hidden {
    -webkit-transform: rotateY(-90deg);
       -moz-transform: rotateY(-90deg);
        -ms-transform: rotateY(-90deg);
         -o-transform: rotateY(-90deg);
            transform: rotateY(-90deg);
  }

  &.open-close {
    -webkit-transition-timing-function: @openClose;
       -moz-transition-timing-function: @openClose;
        -ms-transition-timing-function: @openClose;
         -o-transition-timing-function: @openClose;
            transition-timing-function: @openClose;
  }
  &.close-open {
    -webkit-transition-timing-function: @closeOpen;
       -moz-transition-timing-function: @closeOpen;
        -ms-transition-timing-function: @closeOpen;
         -o-transition-timing-function: @closeOpen;
            transition-timing-function: @closeOpen;
  }
  & .header {
    color: #fff;
  }
  & textarea {
    -webkit-appearance: none;
       -moz-appearance: none;
        -ms-appearance: none;
         -o-appearance: none;
            appearance: none;
    box-shadow: none;
    border-color: #338ec6;
    background: none;
    color: #ffd150;
    display:inline-block;
    vertical-align:middle;
    height: 43px;
  }
  & button {
    background: #FFF;
    color: #0072b8;
  }
}

.arrow {
  -webkit-transition: all .5s;
     -moz-transition: all .5s;
      -ms-transition: all .5s;
       -o-transition: all .5s;
          transition: all .5s;
  position: absolute;
  left: 50%;
  margin-left: -10px;
  width: 20px;
  -webkit-animation: float 1s linear infinite;
     -moz-animation: float 1s linear infinite;
      -ms-animation: float 1s linear infinite;
       -o-animation: float 1s linear infinite;
          animation: float 1s linear infinite;

  &.disabled {
    display: none;
  }
}



@-webkit-keyframes float {
  0% {
    -webkit-transform:translateY(0px);
    opacity: 0;
  }
  50% {
    -webkit-transform:translateY(7px);
    opacity: 1;
  }
  100% {
    -webkit-transform:translateY(15px);
    opacity: 0;
  }
}

@-moz-keyframes float {
  0% {
    -moz-transform:translateY(0px);
    opacity: 0;
  }
  50% {
    -moz-transform:translateY(7px);
    opacity: 1;
  }
  100% {
    -moz-transform:translateY(15px);
    opacity: 0;
  }
}

@-ms-keyframes float {
  0% {
    -ms-transform:translateY(0px);
    opacity: 0;
  }
  50% {
    -ms-transform:translateY(7px);
    opacity: 1;
  }
  100% {
    -ms-transform:translateY(15px);
    opacity: 0;
  }
}

@-o-keyframes float {
  0% {
    -o-transform:translateY(0px);
    opacity: 0;
  }
  50% {
    -o-transform:translateY(7px);
    opacity: 1;
  }
  100% {
   -o-transform:translateY(15px);
    opacity: 0;
  }
}

@keyframes float {
  0% {
    transform:translateY(0px);
    opacity: 0;
  }
  50% {
    transform:translateY(7px);
    opacity: 1;
  }
  100% {
    transform:translateY(15px);
    opacity: 0;
  }
}


& button {
  background: #0072b8;
  color: #fff;
  border: none;
  outline: none;
  -webkit-transition: opacity .2s;
     -moz-transition: opacity .2s;
      -ms-transition: opacity .2s;
       -o-transition: opacity .2s;
          transition: opacity .2s;
  cursor: pointer;

  &:disabled {
    opacity: .25;
  }
}

& .clear {
  width: 20px;
  height: 20px;
  box-sizing: border-box;
  font-family: arial;
  font-size: 20px;
  cursor: pointer;
  border: 1px solid #000;
  border-radius: 50%;
  background-repeat: no-repeat;
  background-image: url("close.svg");
  background-size: 10px 10px;
  background-position: 50% 50%;
  opacity: .2;
  -webkit-transition: opacity .2s;
     -moz-transition: opacity .2s;
      -ms-transition: opacity .2s;
       -o-transition: opacity .2s;
          transition: opacity .2s;
}

/* fix GH buttons glitch */
.github-button {
  display: none;
}
