*, *::before, *::after {
  box-sizing: border-box;
}

html {
  font-size: 18px;
  line-height: 1.5;
  font-weight: 300;
  color: #333;
  font-family: "Nunito Sans", sans-serif;
}

body {
  margin: 0;
  padding: 0;
  height: 100vh;
  background-color: hsl(222, 50%, 95%);
  background-attachment: fixed;
}

.content {
  display: flex;
  margin: 0 auto;
  justify-content: center;
  align-items: center;
  flex-wrap: wrap;
  max-width: 1000px;
}

.heading {
  width: 100%;
  margin-left: 1rem;
  font-weight: 900;
  font-size: 1.618rem;
  text-transform: uppercase;
  letter-spacing: .1ch;
  line-height: 1;
  padding-bottom: .5em;
  margin-bottom: 1rem;
  position: relative;
}

.heading::after {
  display: block;
  content: '';
  position: absolute;
  width: 60px;
  height: 4px;
  background: linear-gradient(135deg, hsl(202, 80%, 50%), hsl(222, 80%, 50%));
  bottom: 0;
}

.description {
  width: 100%;
  margin-top: 0;
  margin-left: 1rem;
  margin-bottom: 3rem;
}

.card {
  color: inherit;
  cursor: pointer;
  width: calc(33% - 2rem);
  min-width: calc(33% - 2rem);
  height: 400px;
  min-height: 400px;
  perspective: 1000px;
  margin: 1rem;
  position: relative;
  overflow: hidden;
}

@media screen and (max-width: 800px) {
  .card {
    width: calc(50% - 2rem);
  }
}

@media screen and (max-width: 500px) {
  .card {
    width: 100%;
  }
}

.front,
.back {
  display: flex;
  border-radius: 6px;
  background-position: center;
  background-size: cover;
  text-align: center;
  justify-content: center;
  align-items: center;
  position: absolute;
  height: 100%;
  width: 100%;
  -webkit-backface-visibility: hidden;
  backface-visibility: hidden;
  transform-style: preserve-3d;
  transition: ease-in-out 600ms;
}

.front {
  padding: 2rem;
  font-size: 1.618rem;
  font-weight: 900;
  color: #fff;
  overflow: hidden;
  font-family: Poppins, sans-serif;
}

.front::before {
  position: absolute;
  display: block;
  content: '';
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: linear-gradient(135deg, hsl(202, 80%, 50%), hsl(222, 80%, 50%));
  opacity: .25;
  z-index: -1;
}

.card:hover .front {
  transform: rotateY(180deg);
}

.card:nth-child(even):hover .front {
  transform: rotateY(-180deg);
}

.back {
  background: #ffffff;
  transform: rotateY(-180deg);
  padding: 0 2em;
}

.card:hover .back {
  transform: rotateY(0deg);
}

.card:nth-child(even) .back {
  transform: rotateY(180deg);
}

.card:nth-child(even) .back .button {
  background: linear-gradient(135deg, hsl(330, 80%, 50%), hsl(350, 80%, 50%));
}

.card:nth-child(even) .back .button::before {
  box-shadow: 0 0 10px 10px rgba(230, 41, 76, 0.25);
  background-color: rgba(230, 41, 76, 0.25);
}

.card:nth-child(even):hover .back {
  transform: rotateY(0deg);
}