/* ZBI Free Tools — shared styles */
:root {
  --zbi-primary: #1a365d;
  --zbi-primary-light: #2c5282;
  --zbi-accent: #3182ce;
  --zbi-success: #276749;
  --zbi-bg: #f7fafc;
  --zbi-card: #ffffff;
  --zbi-border: #e2e8f0;
  --zbi-text: #2d3748;
  --zbi-text-muted: #718096;
  --zbi-error: #c53030;
  --zbi-radius: 8px;
  --zbi-shadow: 0 1px 3px rgba(0,0,0,0.08);
  --zbi-result-bg: #edf2f7;
}

* {
  box-sizing: border-box;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, sans-serif;
  line-height: 1.6;
  color: var(--zbi-text);
  background: var(--zbi-bg);
  margin: 0;
  padding: 0;
}

.zbi-tools-wrap {
  max-width: 640px;
  margin: 0 auto;
  padding: 1.5rem;
}

.zbi-tools-wrap .back-link {
  display: inline-block;
  margin-bottom: 1rem;
  padding: 0.5rem 0;
  color: var(--zbi-accent);
  text-decoration: none;
  font-size: 0.95rem;
  font-weight: 500;
}

.zbi-tools-wrap .back-link:hover {
  text-decoration: underline;
}

h1 {
  font-size: 1.75rem;
  margin: 0 0 0.5rem;
  color: var(--zbi-primary);
}

.subtitle {
  color: var(--zbi-text-muted);
  font-size: 1rem;
  margin: 0 0 1.5rem;
}

/* Form */
.zbi-form {
  background: var(--zbi-card);
  border-radius: var(--zbi-radius);
  box-shadow: var(--zbi-shadow);
  padding: 1.5rem;
  margin-bottom: 1.5rem;
}

.zbi-form-group {
  margin-bottom: 1.25rem;
}

.zbi-form-group:last-of-type {
  margin-bottom: 0;
}

.zbi-form-group label {
  display: block;
  font-weight: 600;
  font-size: 0.9rem;
  margin-bottom: 0.35rem;
  color: var(--zbi-text);
}

.zbi-form-group input,
.zbi-form-group select {
  width: 100%;
  padding: 0.65rem 0.85rem;
  font-size: 1rem;
  border: 1px solid var(--zbi-border);
  border-radius: var(--zbi-radius);
  background: #fff;
  color: var(--zbi-text);
}

.zbi-form-group input:focus,
.zbi-form-group select:focus {
  outline: none;
  border-color: var(--zbi-accent);
  box-shadow: 0 0 0 3px rgba(49, 130, 206, 0.15);
}

.zbi-form-group .hint {
  font-size: 0.8rem;
  color: var(--zbi-text-muted);
  margin-top: 0.25rem;
}

.zbi-error-msg {
  font-size: 0.85rem;
  color: var(--zbi-error);
  margin-top: 0.35rem;
}

/* Tabs (Markup calculator) */
.zbi-tabs {
  display: flex;
  gap: 0;
  margin-bottom: 1.25rem;
  border-bottom: 1px solid var(--zbi-border);
}

.zbi-tab {
  padding: 0.6rem 1rem;
  background: none;
  border: none;
  font-size: 0.95rem;
  color: var(--zbi-text-muted);
  cursor: pointer;
  border-bottom: 2px solid transparent;
  margin-bottom: -1px;
}

.zbi-tab.active {
  color: var(--zbi-accent);
  font-weight: 600;
  border-bottom-color: var(--zbi-accent);
}

.zbi-tab:hover:not(.active) {
  color: var(--zbi-text);
}

.zbi-tab-panel {
  display: none;
}

.zbi-tab-panel.active {
  display: block;
}

/* Buttons */
.zbi-buttons {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin-top: 1.25rem;
}

.zbi-btn {
  padding: 0.75rem 1.5rem;
  min-height: 2.75rem;
  font-size: 1rem;
  font-weight: 600;
  border: none;
  border-radius: var(--zbi-radius);
  cursor: pointer;
  transition: background 0.15s, transform 0.05s;
}

.zbi-btn:active {
  transform: scale(0.98);
}

.zbi-btn-primary {
  background: var(--zbi-accent);
  color: #fff;
}

.zbi-btn-primary:hover {
  background: var(--zbi-primary-light);
}

.zbi-btn-secondary {
  background: var(--zbi-border);
  color: var(--zbi-text);
}

.zbi-btn-secondary:hover {
  background: #cbd5e0;
}

/* Result block */
.zbi-result {
  background: var(--zbi-result-bg);
  border-radius: var(--zbi-radius);
  padding: 1.25rem 1.5rem;
  margin-bottom: 1.5rem;
  border-left: 4px solid var(--zbi-accent);
  box-shadow: var(--zbi-shadow);
}

.zbi-result.hidden {
  display: none;
}

.zbi-result-title {
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--zbi-text-muted);
  margin-bottom: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.03em;
}

.zbi-result-row {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  padding: 0.4rem 0;
  border-bottom: 1px solid rgba(0,0,0,0.06);
}

.zbi-result-row:last-child {
  border-bottom: none;
}

.zbi-result-info {
  margin-top: 0.75rem;
  padding-top: 0.75rem;
  border-top: 1px solid rgba(0, 0, 0, 0.06);
  font-size: 0.9rem;
}

.zbi-result-label {
  font-size: 0.95rem;
  color: var(--zbi-text);
}

.zbi-result-value {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--zbi-primary);
}

.zbi-result-value.highlight {
  font-size: 1.65rem;
  font-weight: 800;
  color: var(--zbi-primary);
  letter-spacing: -0.02em;
}

/* Content sections */
.zbi-section {
  margin-bottom: 2rem;
}

.zbi-section h2 {
  font-size: 1.2rem;
  color: var(--zbi-primary);
  margin: 0 0 0.75rem;
}

.zbi-section p,
.zbi-section ul {
  margin: 0 0 0.75rem;
  color: var(--zbi-text);
}

.zbi-section .zbi-formula-note {
  font-size: 0.9rem;
  color: var(--zbi-text-muted);
  margin-top: 0.35rem;
}

.zbi-section code,
.zbi-formula {
  background: var(--zbi-result-bg);
  padding: 0.15rem 0.4rem;
  border-radius: 4px;
  font-size: 0.9em;
}

.zbi-faq-item {
  margin-bottom: 1rem;
}

.zbi-faq-item h3 {
  font-size: 1rem;
  margin: 0 0 0.35rem;
  color: var(--zbi-text);
}

.zbi-faq-item p {
  margin: 0;
  font-size: 0.95rem;
  color: var(--zbi-text-muted);
}

/* Other calculators list — 2 cols desktop, 1 col mobile */
.zbi-other-calculators {
  line-height: 1.8;
}
.zbi-other-calculators a {
  color: var(--zbi-accent);
  text-decoration: none;
}
.zbi-other-calculators a:hover {
  text-decoration: underline;
}
@media (min-width: 600px) {
  .zbi-other-calculators {
    column-count: 2;
    column-gap: 1.5rem;
  }
}

/* Tools landing — section headings */
.zbi-landing-section {
  margin-bottom: 2.5rem;
}
.zbi-landing-section h2 {
  font-size: 1.15rem;
  color: var(--zbi-primary);
  margin: 0 0 1rem;
  padding-bottom: 0.35rem;
  border-bottom: 1px solid var(--zbi-border);
}

/* Tools landing grid */
.zbi-tools-grid {
  display: grid;
  gap: 1rem;
  margin-top: 1.5rem;
}

.zbi-tool-card {
  display: block;
  background: var(--zbi-card);
  border-radius: var(--zbi-radius);
  box-shadow: var(--zbi-shadow);
  padding: 1.25rem;
  text-decoration: none;
  color: inherit;
  border: 1px solid transparent;
  transition: border-color 0.2s, box-shadow 0.2s;
  min-height: 4rem;
}

.zbi-tool-card:hover {
  border-color: var(--zbi-accent);
  box-shadow: 0 4px 12px rgba(49, 130, 206, 0.15);
}

.zbi-tool-card h2 {
  font-size: 1.15rem;
  margin: 0 0 0.35rem;
  color: var(--zbi-primary);
}

.zbi-tool-card p {
  margin: 0;
  font-size: 0.9rem;
  color: var(--zbi-text-muted);
}

/* Mobile */
@media (max-width: 600px) {
  .zbi-tools-wrap {
    padding: 1rem;
  }

  h1 {
    font-size: 1.5rem;
  }

  .zbi-form {
    padding: 1.25rem;
  }

  .zbi-form-group input,
  .zbi-form-group select {
    padding: 0.75rem 0.85rem;
    min-height: 2.75rem;
  }

  .zbi-result-value {
    font-size: 1.15rem;
  }

  .zbi-result-value.highlight {
    font-size: 1.5rem;
  }

  .zbi-btn {
    min-height: 2.75rem;
    padding: 0.7rem 1.25rem;
  }

  .zbi-tool-card {
    padding: 1rem 1.25rem;
    min-height: 3.5rem;
  }
}