* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: "Trebuchet MS", "Lucida Sans Unicode", "Lucida Grande",
    "Lucida Sans", Arial, sans-serif;
}
body {
  background-color: #86ada0;
}
#start {
  position: absolute;
  left: 50%;
  top: 50%;
  transform: translate(-50%, -50%);
}
#startBtn {
  text-decoration: none;
  display: inline-block;
  background-color: #fff;
  color: #000;
  padding: 1rem 2rem;
  border-radius: 20px;
  font-weight: bold;
  font-size: 1rem;
  border: 2px solid #000;
  transition: all 0.45s;
  box-shadow: 1px 3px 1px 3px rgba(0, 0, 0, 0.4),
    1px 3px 2px 3px rgb(0, 0, 0, 0.4);
  cursor: pointer;
}
#startBtn:hover {
  box-shadow: none;
  transform: translate(1px, 3px);
}
#wrapper > h1 {
  text-align: center;
}

#game {
  background-color: #073c08;
  display: none;
  width: 60%;
  margin: 2rem auto;
  padding: 1rem;
  border-radius: 0.5rem;
  box-shadow: 0 0 3px 4px rgb(0 0 0 / 16%), 1px 1px 2px 2px rgb(0 0 0 / 0%);
}
#game-container {
  width: 100%;
  margin: 0 auto;
  padding: 1rem;
  display: flex;
  flex-wrap: wrap;
}
#game-board {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-evenly;
  width: 100%;
}
.flip-card {
  background-color: transparent;
  width: 22%;
  height: 150px;
  margin: 0.5rem 0;
  perspective: 1000px;
}
.flip-card * {
  width: 100%;
  height: 100%;
}
.inner {
  position: relative;
  text-align: center;
  transition: transform 0.8s;
  transform-style: preserve-3d;
}
.front,
.back {
  position: absolute;
  -webkit-backface-visibility: hidden;
  backface-visibility: hidden;
}
.front {
  background-color: #bbb;
  color: black;
}
.back {
  color: white;
  transform: rotateY(180deg);
}
.back img {
  border: 1px solid #f1f1f1;
  padding: 0.15rem;
}
.flip-card img {
  aspect-ratio: 3/4;
}

@media all and (max-width: 1100px){
  #game{
    width: 80%;
  }
}
@media all and (max-width: 800px){
  #game{
    width: 98%;
    margin-left: 1%;
    margin-right: 1%;
    padding: 0;
  }
}
@media all and (max-width: 600px){
  .flip-card{
    width: 46%;
    height: 50vh;
  }
}