* {
  box-sizing: border-box;
  font-family: 'Poppins', sans-serif;
}

body {
  background: #f7f7f7;
  text-align: center;
  padding: 20px;
  color: #222;
}

h1 {
  margin-bottom: 5px;
}

.game-container {
  display: grid;
  grid-template-columns: repeat(4, 100px);
  gap: 15px;
  justify-content: center;
  margin: 30px auto;
}

.card {
  width: 100px;
  height: 100px;
  perspective: 800px;
  cursor: pointer;
}

.card-inner {
  width: 100%;
  height: 100%;
  transition: transform 0.6s;
  transform-style: preserve-3d;
}

.card.flipped .card-inner {
  transform: rotateY(180deg);
}

.card-front,
.card-back {
  position: absolute;
  width: 100%;
  height: 100%;
  border-radius: 12px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 2rem;
  backface-visibility: hidden;
}

.card-front {
  background: #ff7a00;
  color: #fff;
}

.card-back {
  background: #ffffff;
  transform: rotateY(180deg);
  box-shadow: 0 6px 15px rgba(0,0,0,0.15);
}

button {
  padding: 10px 20px;
  border: none;
  background: #222;
  color: #fff;
  border-radius: 8px;
  cursor: pointer;
}