body {
  font-family: 'Poppins', sans-serif;
  background: linear-gradient(135deg, #ffd1d1 0%, #ff9ecd 100%);
  min-height: 100vh;
  margin: 0;
  padding: 20px;
  display: flex;
  justify-content: center;
  align-items: center;
}

.container {
  width: 100%;
  max-width: 800px;
  margin: 0 auto;
}

.birthday-card {
  background: rgba(255, 255, 255, 0.95);
  padding: 40px;
  border-radius: 20px;
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
  backdrop-filter: blur(5px);
  margin-bottom: 30px;
}

h1 {
  font-family: 'Pacifico', cursive;
  color: #ff4d8d;
  font-size: 2.5rem;
  margin-bottom: 30px;
  text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.1);
}

.message {
  margin: 30px 0;
}

.dear {
  font-size: 1.4rem;
  color: #444;
  margin-bottom: 20px;
}

.birthday-text {
  font-size: 1.2rem;
  color: #666;
  line-height: 1.6;
}

.kpop-intro {
  font-size: 1.1rem;
  color: #888;
  margin-top: 20px;
}

button {
  background: linear-gradient(45deg, #ff4d8d, #ff8cb3);
  color: white;
  border: none;
  padding: 15px 30px;
  font-size: 1.1rem;
  border-radius: 50px;
  cursor: pointer;
  transition: transform 0.2s, box-shadow 0.2s;
  font-family: 'Poppins', sans-serif;
  font-weight: 600;
}

button:hover {
  transform: translateY(-2px);
  box-shadow: 0 5px 15px rgba(255, 77, 141, 0.4);
}

.image-gallery {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  gap: 20px;
  padding: 20px 0;
}

.image-gallery img {
  width: 100%;
  height: 250px;
  object-fit: cover;
  border-radius: 10px;
  box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
  transition: transform 0.3s;
}

.image-gallery img:hover {
  transform: scale(1.05);
}

@keyframes float {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-10px); }
}

.confetti {
  position: fixed;
  width: 10px;
  height: 10px;
  background-color: #ff4d8d;
  animation: fall linear infinite;
}

@keyframes fall {
  to {
    transform: translateY(100vh) rotate(360deg);
  }
}

/* Memory Game Styles */
.memory-game-section {
  background: rgba(255, 255, 255, 0.95);
  padding: 20px;
  border-radius: 20px;
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
  margin-top: 20px;
  text-align: center;
}

.memory-game-container {
  display: none;
  margin-top: 20px;
}

.game-stats {
  display: flex;
  justify-content: space-around;
  margin-bottom: 20px;
  font-size: 1.2rem;
  color: #ff4d8d;
  font-weight: 600;
}

.memory-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 10px;
  max-width: 600px;
  margin: 0 auto;
}

.memory-card {
  aspect-ratio: 1;
  background: linear-gradient(45deg, #ff4d8d, #ff8cb3);
  border-radius: 10px;
  cursor: pointer;
  transition: transform 0.3s;
  transform-style: preserve-3d;
  position: relative;
}

.memory-card:hover {
  transform: scale(1.05);
}

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

.memory-card.matched {
  background: linear-gradient(45deg, #4ecdc4, #a8e6cf);
}

.card-front, .card-back {
  position: absolute;
  width: 100%;
  height: 100%;
  backface-visibility: hidden;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 2rem;
  border-radius: 10px;
}

.card-front {
  background: white;
  transform: rotateY(180deg);
}

.card-back {
  background: linear-gradient(45deg, #ff4d8d, #ff8cb3);
}