* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  background: #0a0a0a;
  color: #e0e0e0;
  overflow: hidden;
}

#game-container {
  position: relative;
  width: 100vw;
  height: 100vh;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  background: #1a1a2e;
  padding-top: 120px;
}

#ui-overlay {
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  padding: 1rem;
  background: rgba(0, 0, 0, 0.8);
  z-index: 10;
  text-align: center;
}

#ui-overlay h1 {
  color: #ffaa00;
  font-size: 2rem;
  margin-bottom: 0.5rem;
  text-shadow: 0 0 10px rgba(255, 170, 0, 0.5);
}

#stats {
  display: flex;
  gap: 2rem;
  justify-content: center;
  font-size: 1rem;
  margin-bottom: 0.5rem;
}

#stats span {
  color: #ffaa00;
  font-weight: bold;
}

#controls-hint {
  font-size: 0.85rem;
  color: #aaa;
}

#game-board {
  display: grid;
  grid-template-columns: repeat(4, 100px);
  gap: 10px;
  padding: 20px;
}

.card {
  width: 100px;
  height: 100px;
  background: #333;
  border: 2px solid #555;
  border-radius: 8px;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 2rem;
  transition: all 0.3s;
  user-select: none;
}

.card:hover {
  border-color: #ffaa00;
  transform: scale(1.05);
}

.card.flipped {
  background: #444;
  border-color: #ffaa00;
}

.card.matched {
  background: #00ff00;
  border-color: #00cc00;
  opacity: 0.5;
  cursor: default;
}

.modal {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: rgba(0, 0, 0, 0.9);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 1000;
}

.modal.hidden {
  display: none;
}

.modal-content {
  background: #1a1a2e;
  border: 2px solid #ffaa00;
  border-radius: 8px;
  padding: 2rem;
  text-align: center;
  min-width: 300px;
}

.modal-content h2 {
  color: #ffaa00;
  margin-bottom: 1rem;
}

button {
  padding: 0.75rem 1.5rem;
  margin: 0.5rem;
  border: none;
  border-radius: 4px;
  font-size: 1rem;
  cursor: pointer;
  font-weight: 500;
}

.btn-primary {
  background: #ffaa00;
  color: #000;
}

.btn-primary:hover {
  background: #ff9900;
}

.btn-secondary {
  background: #444;
  color: #e0e0e0;
}

.btn-secondary:hover {
  background: #555;
}

#submit-status {
  margin-top: 1rem;
  min-height: 1.5rem;
  font-size: 0.9rem;
}

#submit-status.success {
  color: #00ff00;
}

#submit-status.error {
  color: #ff0066;
}