:root {
  --jumbotron-padding-y: 3rem;
}

.jumbotron {
  padding-top: var(--jumbotron-padding-y);
  padding-bottom: var(--jumbotron-padding-y);
  margin-bottom: 0;
  background-color: #fff;
}
@media (min-width: 768px) {
  .jumbotron {
    padding-top: calc(var(--jumbotron-padding-y) * 2);
    padding-bottom: calc(var(--jumbotron-padding-y) * 2);
  }
}

.jumbotron p:last-child {
  margin-bottom: 0;
}

.jumbotron-heading {
  font-weight: 300;
}

.jumbotron .container {
  max-width: 40rem;
}

footer {
  padding-top: 3rem;
  padding-bottom: 3rem;
}

footer p {
  margin-bottom: .25rem;
}

.box-shadow { box-shadow: 0 .25rem .75rem rgba(0, 0, 0, .05); }

#f1_container {
  position: relative;
  margin: 10px auto;
  width: 100%;
  height: 140px;
  z-index: 1;
}
#f1_container {
  perspective: 1000;
}
#f1_card {
  width: 100%;
  height: 100%;
  transform-style: preserve-3d;
  transition: all 0.5s linear;
}
.flipped#f1_container #f1_card {
  -o-transform: rotateY(180deg);
  -ms-transform: rotateY(180deg);
  -moz-transform: rotateY(180deg);
  -webkit-transform: rotateY(180deg);    
  transform: rotateY(180deg);
  /*box-shadow: -5px 5px 5px #aaa;*/
}
.face {
  position: absolute;
  width: 100%;
  height: 100%;
  backface-visibility: hidden;
}
.face.back {
  display: block;
  -o-transform: rotateY(180deg);
  -ms-transform: rotateY(180deg);
  -moz-transform: rotateY(180deg);
  -webkit-transform: rotateY(180deg);  
  transform: rotateY(180deg);
  box-sizing: border-box;
  color: white;
  text-align: center;
  /*background-color: #aaa;*/
}