.simon-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 16px;
  max-width: 400px;
  margin: 0 auto;
}

.simon-btn {
  aspect-ratio: 1;
  border-radius: 16px;
  border: 4px solid rgba(255, 255, 255, 0.1);
  cursor: pointer;
  transition: all 0.1s ease-out;
  position: relative;
}

.simon-btn:active {
  transform: scale(0.95);
}

.simon-btn.active {
  filter: brightness(1.5);
  border-color: rgba(255, 255, 255, 0.8);
  box-shadow: 0 0 20px currentColor;
  transform: scale(0.98);
}

.simon-green {
  background-color: #4ade80;
  color: #4ade80;
}
.simon-red {
  background-color: #f87171;
  color: #f87171;
}
.simon-yellow {
  background-color: #facc15;
  color: #facc15;
}
.simon-blue {
  background-color: #60a5fa;
  color: #60a5fa;
}

.simon-btn::after {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: radial-gradient(
    circle at center,
    rgba(255, 255, 255, 0.2) 0%,
    transparent 70%
  );
  opacity: 0;
  transition: opacity 0.2s;
}

.simon-btn:hover::after {
  opacity: 1;
}

.simon-btn.disabled {
  cursor: not-allowed;
  opacity: 0.8;
}