.advent-calendar {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 10px;
  max-width: 600px;
  margin: 0 auto;
}

.door {
  background: #b71c1c;
  color: #fff;
  padding: 20px;
  text-align: center;
  cursor: pointer;
  border-radius: 8px;
  transition: transform 0.3s ease;
  position: relative;
}

.door.locked {
  background: #555;
  cursor: not-allowed;
  opacity: 0.5;
}

.door.past {
  background: #999;
  cursor: pointer;
  opacity: 0.8;
}

.door.open {
  animation: flash-border 1s infinite alternate;
  box-shadow: 0 0 15px rgba(255, 215, 0, 0.9);
  border: 3px solid #ffd700;
}

@keyframes flash-border {
  from { border-color: #ffd700; }
  to { border-color: #ff4500; }
}

.door.open:hover {
  transform: scale(1.05);
  background: #d32f2f;
}

#advent-popup {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(0,0,0,0.7);
  display: flex;
  justify-content: center;
  align-items: center;
  z-index: 1000;
}

#advent-popup .popup-content {
  background: #fff;
  padding: 20px;
  border-radius: 10px;
  max-width: 400px;
  text-align: center;
}

#advent-popup img {
  max-width: 100%;
  height: auto;
  margin-bottom: 10px;
}

.advent-description {
  margin: 10px 0;
  font-size: 0.95em;
}