/* Calculator Grid Layout */
.calculator-section {
  padding: 3rem 0;
}

.calc-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: 2rem;
  margin-top: 2rem;
}

.calc-card-view {
  display: flex;
  flex-direction: column;
  height: 100%;
  transition: transform 0.3s cubic-bezier(0.4, 0, 0.2, 1), box-shadow 0.3s ease;
  position: relative;
  overflow: hidden;
}

.calc-card-view:hover {
  transform: translateY(-8px);
  box-shadow: var(--glass-shadow), var(--glow-hover);
  border-color: var(--primary);
}

.calc-sidebar::-webkit-scrollbar {
  width: 6px;
}
.calc-sidebar::-webkit-scrollbar-track {
  background: var(--bg-color);
  border-radius: 4px;
}
.calc-sidebar::-webkit-scrollbar-thumb {
  background: var(--border-color);
  border-radius: 4px;
}

.mode-btn {
  display: block;
  width: 100%;
  text-align: left;
  padding: 1rem;
  background: transparent;
  border: 1px solid transparent;
  border-radius: var(--radius-md);
  color: var(--text-secondary);
  font-family: var(--font-family);
  font-size: 0.95rem;
  font-weight: 500;
  cursor: pointer;
  transition: var(--transition);
  margin-bottom: 0.5rem;
}

.mode-btn:hover {
  background: var(--bg-color);
  color: var(--text-primary);
}

.mode-btn.active {
  background: var(--surface-color);
  border-color: var(--border-color);
  color: var(--primary);
  box-shadow: 0 2px 4px rgba(0,0,0,0.05);
  font-weight: 600;
}

.calc-card-header {
  margin-bottom: 1.5rem;
  padding-bottom: 1rem;
  border-bottom: 1px solid var(--border-color);
}

.calc-card-header h3 {
  font-size: 1.25rem;
  color: var(--primary);
  margin-bottom: 0.25rem;
}

.calc-card-header p {
  margin: 0;
  font-size: 0.85rem;
  color: var(--text-secondary);
}

/* Inputs grid inside card */
.input-stack {
  display: flex;
  flex-direction: column;
  gap: 1rem;
  margin-bottom: 1.5rem;
  flex-grow: 1;
}

.input-wrapper {
  position: relative;
}

.input-icon {
  position: absolute;
  right: 1rem;
  top: 50%;
  transform: translateY(-50%);
  color: var(--text-secondary);
  pointer-events: none;
}

.form-control.has-icon {
  padding-right: 2.5rem;
}

/* Results Area */
.result-area {
  background: var(--bg-color);
  border-radius: var(--radius-md);
  padding: 1.5rem;
  margin-top: auto;
  border: 1px solid var(--border-color);
  transition: all 0.3s ease;
}

.result-value {
  font-size: 2rem;
  font-weight: 800;
  color: var(--text-primary);
  margin-bottom: 0.5rem;
  word-break: break-all;
}

.result-steps {
  margin-top: 1rem;
  padding-top: 1rem;
  border-top: 1px solid var(--border-color);
  font-size: 0.85rem;
  animation: fadeIn 0.4s ease-out;
}

.formula-box {
  background: var(--surface-color);
  padding: 0.75rem;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border-color);
  margin-top: 0.75rem;
  font-family: monospace;
  color: var(--primary);
  font-size: 0.9rem;
  overflow-x: auto;
}

/* Animations */
@keyframes fadeIn {
  from { opacity: 0; transform: translateY(5px); }
  to { opacity: 1; transform: translateY(0); }
}

@keyframes popIn {
  0% { opacity: 0; transform: scale(0.95) translateY(20px); }
  100% { opacity: 1; transform: scale(1) translateY(0); }
}

.calc-card-view {
  animation: popIn 0.6s cubic-bezier(0.34, 1.56, 0.64, 1) backwards;
}

.calc-card-view:nth-child(1) { animation-delay: 0.05s; }
.calc-card-view:nth-child(2) { animation-delay: 0.1s; }
.calc-card-view:nth-child(3) { animation-delay: 0.15s; }
.calc-card-view:nth-child(4) { animation-delay: 0.2s; }
.calc-card-view:nth-child(5) { animation-delay: 0.25s; }
.calc-card-view:nth-child(n+6) { animation-delay: 0.3s; }