style.css

* {
  padding: 0;
  margin: 0;
  box-sizing: border-box;
  font-family: "Poppins", sans-serif;
}
body {
  background-color: hwb(34 2% 7%);
}
.wrapper {
  box-sizing: content-box;
  width: 26.87em;
  padding: 2.5em 3em;
  background-color: #ffffff;
  position: absolute;
  transform: translate(-50%, -50%);
  left: 50%;
  top: 50%;
  border-radius: 0.6em;
  box-shadow: 0 0.9em 2.8em rgba(86, 66, 0, 0.2);
}
.game-container {
  position: relative;
  width: 100%;
  display: grid;
  gap: 0.6em;
}
.stats-container {
  text-align: right;
  margin-bottom: 1.2em;
}
.stats-container span {
  font-weight: 600;
}
.card-container {
  position: relative;
  width: 6.25em;
  height: 6.25em;
  cursor: pointer;
}
.card-container img{
  width: 5.8em;
  height: 5.8em;
}
.card-before,
.card-after {
  position: absolute;
  border-radius: 5px;
  width: 100%;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: center;
  border: 4px solid #000000;
  transition: transform 0.7s ease-out;
  backface-visibility: hidden;
}
.card-before {
  background-color: #ecde10;
  font-size: 2.8em;
  font-weight: 600;
}
.card-after {
  background-color: #ffffff;
  transform: rotateY(180deg);
}
.card-container.flipped .card-before {
  transform: rotateY(180deg);
}
.card-container.flipped .card-after {
  transform: rotateY(0deg);
}
.controls-container {
  position: absolute;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-direction: column;
  width: 100%;
  height: 100%;
  background-color: #f4c531;
  top: 0;
}
button {
  border: none;
  border-radius: 0.3em;
  padding: 1em 1.5em;
  cursor: pointer;
}
#stop {
  font-size: 1.1em;
  display: block;
  margin: 1.1em auto 0 auto;
  background-color: #000000;
  color: #ffffff;
}
.controls-container button {
  font-size: 1.3em;
  box-shadow: 0 0.6em 2em rgba(86, 66, 0, 0.2);
}
.hide {
  display: none;
}
#result {
  text-align: center;
}
#result h2 {
  font-size: 2.5em;
}
#result h4 {
  font-size: 1.8em;
  margin: 0.6em 0 1em 0;
}