body {
  font-family: Arial, sans-serif;
  background: url("green-bg.png") no-repeat center center fixed;
  background-size: cover;
  text-align: center;
  padding: 30px;
}
h1 {
  color: #4a7c59;
}
.card-container {
  display: flex;
  justify-content: center;
  gap: 20px;
  margin-top: 40px;
  flex-wrap: wrap;
  direction: rtl;
}
.card {
  width: 150px;
  height: 200px;
  perspective: 1000px;
  cursor: pointer;
  margin: 10px;
}
.card-inner {
  position: relative;
  width: 100%;
  height: 100%;
  transition: transform 0.6s;
  transform-style: preserve-3d;
}
.card.flipped .card-inner {
  transform: rotateY(180deg);
}
.card-face {
  position: absolute;
  width: 100%;
  height: 100%;
  backface-visibility: hidden;
  display: flex;
  justify-content: center;
  align-items: center;
  border: 2px solid #4a7c59;
  border-radius: 12px;
  background: #fff;
  font-size: 60px;
  color: #333;
}
.card-back {
  transform: rotateY(180deg);
  font-size: 40px;
  color: #4a7c59;
}
#instruction {
  font-size: 24px;
  color: #4a7c59;
  margin-top: 20px;
}
#nextLevelBtn, #restartGameBtn {
  margin-top: 30px;
  padding: 10px 20px;
  font-size: 20px;
  border: none;
  background: #4a7c59;
  color: white;
  border-radius: 8px;
  cursor: pointer;
  display: none;
}
#congrats {
  font-size: 28px;
  color: #4a7c59;
  margin-top: 40px;
}