body {
  margin: 0;
  height: 100vh;
  display: flex;
  justify-content: center;
  align-items: center;
  background: linear-gradient(135deg, #ff7eb3, #65d6ce);
  font-family: Arial, sans-serif;
}

.grid {
  display: grid;
  grid-template-columns: repeat(4, 100px);
  grid-gap: 20px;
  perspective: 1000px;
}

.card {
  width: 100px;
  height: 100px;
  position: relative;
  transform-style: preserve-3d;
  transition: transform 0.6s;
  cursor: pointer;
}

.card.flip {
  transform: rotateY(180deg);
}

.face {
  position: absolute;
  width: 100%;
  height: 100%;
  backface-visibility: hidden;
  display: flex;
  justify-content: center;
  align-items: center;
}

.front {
  background: #ccc;
  border-radius: 50%;
}

.back {
  transform: rotateY(180deg);
}

.circle {
  background: #ff6b6b;
  border-radius: 50%;
}

.rectangle {
  background: #4dabf7;
  border-radius: 10px;
}

.star {
  width: 0;
  height: 0;
  background: none;
  position: relative;
}

.star::before {
  content: "";
  position: absolute;
  top: -20px;
  left: 20px;
  border-left: 20px solid transparent;
  border-right: 20px solid transparent;
  border-bottom: 40px solid gold;
}

.star::after {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  border-left: 20px solid transparent;
  border-right: 20px solid transparent;
  border-top: 40px solid gold;
}

/*.triangle {
  width: 0;
  height: 0;
  border-left: 50px solid transparent;
  border-right: 50px solid transparent;
  border-bottom: 100px solid #51cf66;
  transform: scale(0.5);
}*/

.emoji {
  font-size: 40px;
}