*{
  -webkit-box-sizing: border-box;
          box-sizing: border-box;
}
/* autoprefixer grid: autoplace */
h1,
h2,
p{
  margin: 0;
  padding: 0;
}
#game-box{
  max-width: 1140px;
  margin: auto;
}
#game-memory{
  display: -webkit-box;
  display: -ms-flexbox;
  display: flex;
  -webkit-box-pack: justify;
      -ms-flex-pack: justify;
          justify-content: space-between;
  text-align: center;
  padding: 10px;
}
#btn-start{
  width: 100px;
  border-radius: 5px;
  font-weight: bold;
  font-size: 15px;
  cursor: pointer;
}
#container{
  width: 100%;
  border-top: 1px solid #000;
  display: -ms-grid;
  display: grid;
  -ms-grid-columns: 1fr 15px 1fr 15px 1fr 15px 1fr 15px 1fr;
  grid-template-columns: repeat(5, 1fr);
  grid-gap: 15px;
  padding: 15px;
  position: relative;
}
.item{
  width: 150px;
  height: 150px;
  text-align: center;
  position: relative;
  border: 1px solid #000;
  border-radius:  5px;
  padding: 10px;
  display: -webkit-box;
  display: -ms-flexbox;
  display: flex;
  text-align: center;
  -webkit-box-pack: center;
      -ms-flex-pack: center;
          justify-content: center;
}
.card {
  width: 200px;
  height: 260px;
  -webkit-transition: -webkit-transform 1s;
  transition: -webkit-transform 1s;
  -o-transition: transform 1s;
  transition: transform 1s;
  transition: transform 1s, -webkit-transform 1s;
  -webkit-transform-style: preserve-3d;
          transform-style: preserve-3d;
  cursor: pointer;
  position: relative;
  border: 1px solid #000;
  border-radius: 10px;
  background-color: #fff;
}
.is-flipped {
  -webkit-transform: rotateY(180deg);
          transform: rotateY(180deg);
}
img{
  -o-object-fit: cover;
     object-fit: cover;
}
.card__face {
  position: absolute;
  width: 100%;
  height: 100%;
  text-align: center;
  display: -webkit-box;
  display: -ms-flexbox;
  display: flex;
  -webkit-box-pack: center;
      -ms-flex-pack: center;
          justify-content: center;
  border-radius: 10px;
}
.fix-card{
  padding: 10px;
}
.fix-card > img{
  -o-object-fit: contain;
     object-fit: contain;
  width: 100%;
  height: 100%;
}
.card__face--back {
  -webkit-transform: rotateY(180deg);
          transform: rotateY(180deg);
  border: 1px solid #000;
  border-radius: 10px;
}
.card__face--back > img {
  width: 100%;
  height: 100%;
}