:root {
  --card-bg: var(--surface);
  --card-border: var(--border);
  --input-bg: var(--surface-2);
  --input-border: transparent;
  --focus-ring: var(--primary);
}

.calc-grid {
    display: flex;
    flex-direction: column;
    gap: 32px;
}

.calc-card {
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: 24px;
  padding: 28px;
  box-shadow: var(--shadow);
  display: flex;
  flex-direction: column;
  gap: 24px;
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.calc-card:hover {
  transform: translateY(-2px);
  box-shadow: 0 20px 40px rgba(0,0,0,0.1);
}

.card-header {
  border-bottom: 1px solid var(--border);
  padding-bottom: 16px;
  margin-bottom: 8px;
}

.card-header h3 {
  margin: 0 0 8px;
  font-size: 1.3rem;
  font-weight: 700;
  color: var(--text);
}

.card-header p {
  margin: 0;
  color: var(--muted);
  font-size: 0.95rem;
  line-height: 1.5;
}

/* Ratio Specific Layout */
.ratio-base,
.ratio-target {
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  align-items: end;
  gap: 12px;
}

.ratio-sep {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--muted);
  padding-bottom: 14px;
  text-align: center;
}

/* Common Field Styles */
.field {
  display: flex;
  flex-direction: column;
  gap: 8px;
  width: 100%;
}

.field-label {
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--muted);
  margin-left: 4px;
}

.field input:focus {
  outline: none;
  background: var(--bg);
  border-color: var(--focus-ring);
  box-shadow: 0 0 0 4px rgba(106, 167, 255, 0.1);
}

.field input::placeholder {
  color: var(--muted);
  opacity: 0.6;
}

.hint {
  margin: -8px 0 0;
  color: var(--muted);
  font-size: 0.85rem;
  text-align: center;
  background: var(--surface-2);
  padding: 8px 12px;
  border-radius: 8px;
}

/* Percentage Section Stacks */
.stack {
  background: var(--surface-2);
  border-radius: 16px;
  padding: 20px;
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.stack-header h4 {
  margin: 0;
  font-size: 1rem;
  font-weight: 600;
  color: var(--text);
  display: flex;
  align-items: center;
  gap: 8px;
}

.stack-header h4::before {
  content: '';
  display: block;
  width: 4px;
  height: 16px;
  background: var(--primary);
  border-radius: 2px;
}

.field-row {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(120px, 1fr));
  gap: 12px;
}

/* Result Styles */
.result-block {
  display: flex;
  align-items: center;
  justify-content: space-between;
  background: var(--surface);
  padding: 16px 20px;
  border-radius: 12px;
  border: 1px solid var(--border);
  margin-top: 4px;
}

.result-label {
  font-size: 0.9rem;
  color: var(--muted);
  font-weight: 500;
}

.result-value {
  font-size: 1.4rem;
  font-weight: 700;
  color: var(--primary);
  font-feature-settings: "tnum";
}

/* Result Display - Centered Layout */
.result-display {
  display: flex;
  flex-direction: column;
  gap: 12px;
  align-items: center;
  background: var(--surface);
  padding: 20px;
  border-radius: 12px;
  border: 1px solid var(--border);
  margin-top: 8px;
}

.result-item-centered {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 8px;
  text-align: center;
}

.result-item-centered .result-value {
  font-size: 1.6rem;
  font-weight: 700;
  color: var(--primary);
}

.result-item-centered .result-label {
  font-size: 0.85rem;
  color: var(--muted);
  font-weight: 500;
}

/* Percentage Grid - One card per row */
.percentage-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 24px;
  align-items: start;
}

@media (max-width: 768px) {
  .hero {
    margin: 20px 0 30px;
    text-align: left;
  }
 
  .calc-grid {
    grid-template-columns: 1fr;
  }

  .percentage-grid {
    grid-template-columns: 1fr;
  }
}