:root {
  --surface: #FFFFFF;
  --surface-subtle: #F8FAFC;
  --surface-alt: #F1F5F9;
  --border: #E2E8F0;
  --border-dark: #CBD5E1;
  --text-primary: #0F172A;
  --text-secondary: #475569;
  --text-muted: #64748B;
  --primary-dark: #0F172A;
  --accent-slider: #0F172A;
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 14px;
  --shadow-sm: 0 1px 3px 0 rgba(0, 0, 0, 0.04);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.05);
  --font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, -apple-system, sans-serif;
}

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
  -webkit-tap-highlight-color: transparent;
}

body {
  font-family: var(--font-family);
  background-color: var(--surface-subtle);
  color: var(--text-primary);
  line-height: 1.5;
  padding-bottom: 48px;
  -webkit-font-smoothing: antialiased;
}

.app-container {
  max-width: 920px;
  margin: 0 auto;
  padding: 20px 16px;
}

/* Header */
.app-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding-bottom: 20px;
  border-bottom: 1px solid var(--border);
  margin-bottom: 24px;
}

.brand {
  display: flex;
  align-items: center;
}

.app-title {
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--text-primary);
  letter-spacing: -0.01em;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 8px;
}

.nav-link {
  display: inline-flex;
  align-items: center;
  font-size: 0.8125rem;
  font-weight: 500;
  color: var(--text-secondary);
  text-decoration: none;
  padding: 6px 12px;
  border-radius: var(--radius-sm);
  background-color: var(--surface);
  border: 1px solid var(--border);
  transition: all 0.15s ease;
  min-height: 32px;
}

.nav-link:hover {
  background-color: var(--surface-alt);
  color: var(--text-primary);
  border-color: var(--border-dark);
}

/* Hero Section */
.calculator-hero {
  margin: 4px 0 24px;
}

.hero-title {
  font-size: 1.45rem;
  font-weight: 700;
  color: var(--text-primary);
  line-height: 1.25;
  letter-spacing: -0.025em;
  margin-bottom: 8px;
}

@media (min-width: 640px) {
  .hero-title {
    font-size: 1.75rem;
  }
}

.hero-subtext {
  font-size: 0.875rem;
  color: var(--text-secondary);
  line-height: 1.5;
  margin-bottom: 8px;
}

.hero-meta-link {
  display: inline-flex;
  align-items: center;
  font-size: 0.8125rem;
  font-weight: 500;
  color: var(--text-primary);
  text-decoration: underline;
  text-underline-offset: 3px;
  transition: color 0.15s ease;
}

.hero-meta-link:hover {
  color: var(--text-secondary);
}

/* Projection Summary Cards */
.projection-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
  margin-bottom: 32px;
}

.projection-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 16px;
  box-shadow: var(--shadow-sm);
}

.projection-card.full-width {
  grid-column: span 2;
  background: #0F172A;
  color: #FFFFFF;
  border: 1px solid #1E293B;
  padding: 20px;
}

.projection-card .card-label {
  font-size: 0.6875rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--text-muted);
  margin-bottom: 6px;
}

.projection-card.full-width .card-label {
  color: #94A3B8;
}

.projection-card .card-value {
  font-size: 1.35rem;
  font-weight: 700;
  color: var(--text-primary);
  font-variant-numeric: tabular-nums;
  line-height: 1.2;
}

.projection-card.full-width .card-value {
  font-size: 1.85rem;
  color: #FFFFFF;
}

.card-subvalue {
  font-size: 0.8125rem;
  font-weight: 500;
  color: var(--text-muted);
  font-variant-numeric: tabular-nums;
  margin-top: 4px;
}

.projection-card.full-width .card-subvalue {
  font-size: 0.875rem;
  color: #CBD5E1;
}

.tax-badge {
  font-size: 0.75rem;
  color: #94A3B8;
  margin-top: 6px;
}

/* Section Heading Above Cards */
.section-heading {
  margin-bottom: 16px;
}

.section-heading-title {
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--text-primary);
  letter-spacing: -0.015em;
  margin-bottom: 4px;
}

.section-heading-sub {
  font-size: 0.8125rem;
  color: var(--text-secondary);
  line-height: 1.45;
}

/* Main Two-Card Input Grid */
.calculator-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 16px;
  margin-bottom: 24px;
}

@media (min-width: 768px) {
  .calculator-grid {
    grid-template-columns: 1fr 1fr;
    gap: 16px;
  }
}

.input-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 20px;
  box-shadow: var(--shadow-sm);
  display: flex;
  flex-direction: column;
}

.card-header-title {
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 6px;
}

.card-header-desc {
  font-size: 0.8125rem;
  color: var(--text-secondary);
  line-height: 1.45;
  margin-bottom: 20px;
}

/* Mode Switch (Estimate | Exact) */
.segmented-control {
  display: inline-flex;
  background-color: var(--surface-alt);
  padding: 3px;
  border-radius: 9999px;
  margin-bottom: 18px;
  border: 1px solid var(--border);
  width: fit-content;
}

.segment-btn {
  border: none;
  background: transparent;
  padding: 4px 14px;
  font-size: 0.75rem;
  font-weight: 600;
  border-radius: 9999px;
  color: var(--text-secondary);
  cursor: pointer;
  transition: all 0.15s ease;
  min-height: 28px;
}

.segment-btn.active {
  background: var(--surface);
  color: var(--text-primary);
  box-shadow: 0 1px 2px rgba(0, 0, 0, 0.05);
}

/* Input Rows */
.input-row {
  margin-bottom: 18px;
}

.input-row-header {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  margin-bottom: 8px;
  gap: 12px;
}

.input-row-labels {
  display: flex;
  flex-direction: column;
  flex: 1;
}

.input-label-main {
  font-size: 0.8125rem;
  font-weight: 600;
  color: var(--text-primary);
}

.input-label-sub {
  font-size: 0.75rem;
  color: var(--text-muted);
  margin-top: 2px;
}

.pill-number-input {
  width: 80px;
  padding: 6px 10px;
  font-size: 0.875rem;
  font-weight: 600;
  text-align: right;
  border: 1px solid var(--border-dark);
  border-radius: var(--radius-sm);
  background-color: var(--surface);
  color: var(--text-primary);
  font-variant-numeric: tabular-nums;
  min-height: 34px;
}

.pill-number-input:focus {
  outline: none;
  border-color: var(--primary-dark);
  box-shadow: 0 0 0 2px rgba(15, 23, 42, 0.08);
}

/* Minimalist Range Slider */
.slider-wrapper {
  margin-top: 4px;
}

.styled-range {
  -webkit-appearance: none;
  appearance: none;
  width: 100%;
  height: 4px;
  border-radius: 9999px;
  background: #E2E8F0;
  outline: none;
  cursor: pointer;
}

.styled-range::-webkit-slider-thumb {
  -webkit-appearance: none;
  appearance: none;
  width: 16px;
  height: 16px;
  border-radius: 50%;
  background: var(--accent-slider);
  cursor: pointer;
  box-shadow: 0 1px 2px rgba(0, 0, 0, 0.15);
  transition: transform 0.1s ease;
}

.styled-range::-webkit-slider-thumb:hover {
  transform: scale(1.15);
}

.styled-range::-moz-range-thumb {
  width: 16px;
  height: 16px;
  border-radius: 50%;
  background: var(--accent-slider);
  cursor: pointer;
  border: none;
  box-shadow: 0 1px 2px rgba(0, 0, 0, 0.15);
}

/* Minimal Summary Banner */
.summary-banner {
  margin-top: auto;
  background-color: var(--surface-subtle);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 10px 12px;
  font-size: 0.8125rem;
  color: var(--text-secondary);
  line-height: 1.45;
}

.summary-banner strong {
  color: var(--text-primary);
  font-weight: 600;
}

/* Breakdown Card */
.breakdown-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 20px;
  margin-top: 24px;
  box-shadow: var(--shadow-sm);
}

.breakdown-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.8125rem;
  margin-top: 12px;
}

.breakdown-table th {
  text-align: left;
  padding: 8px 4px;
  color: var(--text-muted);
  font-weight: 500;
  border-bottom: 1px solid var(--border);
}

.breakdown-table td {
  padding: 10px 4px;
  border-bottom: 1px solid var(--border);
  font-variant-numeric: tabular-nums;
  color: var(--text-secondary);
}

.breakdown-table tr:last-child td {
  border-bottom: none;
}

.breakdown-table td.text-right, .breakdown-table th.text-right {
  text-align: right;
}

.tax-row {
  color: var(--text-muted);
}

.total-row {
  font-weight: 700;
  font-size: 0.875rem;
  color: var(--text-primary);
}

/* FAQ Page Styles */
.faq-header {
  text-align: center;
  margin: 16px 0 28px;
}

.faq-title {
  font-size: 1.65rem;
  font-weight: 700;
  color: var(--text-primary);
  letter-spacing: -0.025em;
}

.accordion-list {
  display: flex;
  flex-direction: column;
  gap: 10px;
  max-width: 680px;
  margin: 0 auto;
}

.accordion-item {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-sm);
  overflow: hidden;
  transition: border-color 0.15s ease;
}

.accordion-trigger {
  width: 100%;
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 16px 18px;
  background: none;
  border: none;
  text-align: left;
  cursor: pointer;
  gap: 16px;
}

.accordion-question {
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--text-primary);
  line-height: 1.35;
}

.accordion-icon {
  font-size: 1.1rem;
  font-weight: 400;
  color: var(--text-muted);
  line-height: 1;
}

.accordion-content {
  padding: 0 18px 18px;
  font-size: 0.8125rem;
  line-height: 1.6;
  color: var(--text-secondary);
  display: none;
}

.accordion-item.open .accordion-content {
  display: block;
}

.accordion-item.open .accordion-icon {
  transform: rotate(45deg);
  color: var(--text-primary);
}

/* Forms in Settings Page */
.form-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 20px;
  box-shadow: var(--shadow-sm);
  margin-bottom: 16px;
}

.form-group {
  margin-bottom: 16px;
}

.form-group:last-child {
  margin-bottom: 0;
}

.form-label {
  display: block;
  font-size: 0.8125rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 6px;
}

.form-hint {
  font-size: 0.75rem;
  color: var(--text-muted);
  margin-top: 4px;
}

.form-input {
  width: 100%;
  padding: 8px 12px;
  font-size: 0.875rem;
  border: 1px solid var(--border-dark);
  border-radius: var(--radius-sm);
  background-color: var(--surface);
  color: var(--text-primary);
  min-height: 40px;
  font-variant-numeric: tabular-nums;
}

.form-input:focus {
  outline: none;
  border-color: var(--primary-dark);
  box-shadow: 0 0 0 2px rgba(15, 23, 42, 0.08);
}

.btn-group {
  display: flex;
  flex-direction: column;
  gap: 10px;
  margin-top: 20px;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-size: 0.875rem;
  font-weight: 600;
  padding: 10px 16px;
  border-radius: var(--radius-sm);
  border: none;
  cursor: pointer;
  min-height: 40px;
  transition: all 0.15s ease;
}

.btn-primary {
  background-color: #0F172A;
  color: #FFFFFF;
}

.btn-primary:hover, .btn-primary:active {
  background-color: #1E293B;
}

.btn-secondary {
  background-color: var(--surface);
  color: var(--text-secondary);
  border: 1px solid var(--border-dark);
}

.btn-secondary:hover, .btn-secondary:active {
  background-color: var(--surface-alt);
}

/* Toast message */
.toast {
  position: fixed;
  bottom: 20px;
  left: 50%;
  transform: translateX(-50%) translateY(100px);
  background-color: #0F172A;
  color: #FFFFFF;
  padding: 8px 16px;
  border-radius: 9999px;
  font-size: 0.8125rem;
  font-weight: 500;
  box-shadow: var(--shadow-md);
  opacity: 0;
  transition: all 0.25s ease;
  z-index: 1000;
  pointer-events: none;
}

.toast.show {
  transform: translateX(-50%) translateY(0);
  opacity: 1;
}