/* Base button styling */
.calc-btn {
  padding: 1.25rem;
  font-size: 2rem;
  font-weight: 700;
  text-align: center;
  cursor: pointer;
  transition: all 0.3s ease;
  box-shadow: 0 4px 15px rgba(0, 0, 0, 0.2);
}

/* Hover/active effects */
.calc-btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 25px rgba(0, 0, 0, 0.3);
}
.calc-btn:active {
  transform: scale(0.95);
  box-shadow: inset 0 2px 4px rgba(0, 0, 0, 0.2);
}

/* Color themes */
.calc-btn.bg-red-500 {
  background: #ef4444;
  color: white;
}
.calc-btn.bg-yellow-400 {
  background: #fbbf24;
  color: black;
}
.calc-btn.bg-purple-500 {
  background: #9333ea;
  color: white;
}
.calc-btn.bg-orange-500 {
  background: #f97316;
  color: white;
}
.calc-btn.bg-emerald-500 {
  background: #10b981;
  color: white;
}

/* Zero button spans 2 columns */
.calc-btn {
  border-radius: 9999px;
}

/* Responsive fonts */
@media (max-width: 480px) {
  .calc-btn {
    font-size: 1.5rem;
    padding: 0.75rem;
  }
}