/* Design tokens */
:root {
  --color-ev:        #2e7d32;
  --color-ev-light:  #e8f5e9;
  --color-gas:       #c62828;
  --color-gas-light: #ffebee;
  --color-bg:        #d7dedf;
  --color-surface:   #ffffff;
  --color-border:    #dee2e6;
  --color-text:      #212529;
  --color-muted:     #6c757d;
  --color-accent:    #1565c0;
  --radius:          8px;
  --radius-lg:       12px;
  --shadow:          0 1px 4px rgba(0,0,0,0.10);
  --shadow-lg:       0 4px 16px rgba(0,0,0,0.12);
  --spacing:         8px;
  --font:            system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  --font-mono:       "Courier New", Courier, monospace;
}

/* Reset & base */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

html { font-size: 16px; scroll-behavior: smooth; }

body {
  font-family: var(--font);
  background: var(--color-bg);
  color: var(--color-text);
  line-height: 1.6;
  min-height: 100vh;
}

a { color: var(--color-accent); text-decoration: none; }
a:hover { text-decoration: underline; }

img { max-width: 100%; height: auto; display: block; }

button {
  cursor: pointer;
  font-family: var(--font);
  border: none;
  background: none;
}

input, select {
  font-family: var(--font);
  font-size: 1rem;
  color: var(--color-text);
}

/* Layout */
.container {
  max-width: 1080px;
  margin: 0 auto;
  padding: 0 calc(var(--spacing) * 2);
}

/* Header */
.site-header {
  background: var(--color-surface);
  border-bottom: 1px solid var(--color-border);
  padding: calc(var(--spacing) * 1.25) 0;
  position: sticky;
  top: 0;
  z-index: 100;
  box-shadow: var(--shadow);
}

.site-header .container {
  display: flex;
  align-items: center;
  gap: calc(var(--spacing) * 2);
}

.site-title {
  font-size: 1.3rem;
  font-weight: 700;
  color: var(--color-ev);
}

.site-tagline {
  font-size: 1.25rem;
  color: var(--color-muted);
  flex: 1;
}

.brand-wordmark {
  height: 30px;
  width: auto;
  flex-shrink: 0;
}

.bcit-logo {
  height: 36px;
  width: auto;
  flex-shrink: 0;
}

/* Intro section */
.intro-section {
  padding: calc(var(--spacing) * 3) 0 0;
}
.intro-section .container {
  background: var(--color-surface);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: calc(var(--spacing) * 2.5) calc(var(--spacing) * 2);
}
.intro-section h1 {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--color-text);
  margin-bottom: calc(var(--spacing) * 1.5);
}
.intro-section h2 {
  font-size: 1rem;
  font-weight: 700;
  color: var(--color-text);
  margin: calc(var(--spacing) * 1.5) 0 var(--spacing);
}
.intro-section p {
  color: var(--color-muted);
  margin-bottom: var(--spacing);
  line-height: 1.6;
}
.intro-section ul {
  color: var(--color-muted);
  padding-left: calc(var(--spacing) * 4);
  line-height: 1.8;
  margin-bottom: var(--spacing);
  list-style-type: disc;
}

/* Main content */
main { padding: calc(var(--spacing) * 3) 0; }

/* Cards / Sections */
.card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: calc(var(--spacing) * 3);
  margin-bottom: calc(var(--spacing) * 3);
  box-shadow: var(--shadow);
}

.section-header {
  display: flex;
  align-items: center;
  gap: var(--spacing);
  margin-bottom: calc(var(--spacing) * 2);
}

.step-badge {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 28px;
  height: 28px;
  border-radius: 50%;
  background: var(--color-accent);
  color: #fff;
  font-size: 0.8rem;
  font-weight: 700;
  flex-shrink: 0;
}

.section-title {
  font-size: 1.1rem;
  font-weight: 600;
}

/* Category card grid */
.category-grid {
  display: grid;
  grid-template-columns: repeat(6, 1fr);
  gap: calc(var(--spacing) * 1.5);
}

.category-card {
  border: 2px solid var(--color-border);
  border-radius: var(--radius);
  padding: var(--spacing);
  text-align: center;
  transition: border-color 0.15s, box-shadow 0.15s, background 0.15s;
  background: var(--color-surface);
  cursor: pointer;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: flex-start;
}

.category-card:hover {
  border-color: var(--color-accent);
  box-shadow: 0 2px 8px rgba(21,101,192,0.15);
}

.category-card.selected {
  border-color: var(--color-ev);
  background: var(--color-ev-light);
  box-shadow: 0 2px 8px rgba(46,125,50,0.2);
}

.category-img-wrap {
  width: 100%;
  aspect-ratio: 4/3;
  background: var(--color-bg);
  border-radius: calc(var(--radius) - 2px);
  overflow: hidden;
  margin-bottom: var(--spacing);
  display: flex;
  align-items: flex-end;
  justify-content: center;
  padding-bottom: 22px;
}

.category-img-wrap img {
  width: 100%;
  height: 100%;
  object-fit: contain;
  object-position: center bottom;
}

.category-name {
  font-weight: 600;
  font-size: 0.85rem;
  margin-bottom: 2px;
}

.category-examples-label {
  font-size: 0.75rem;
  font-weight: 900;
  color: var(--color-muted);
  margin-bottom: 2px;
}

.category-examples {
  font-size: 0.72rem;
  color: var(--color-muted);
  line-height: 1.3;
}

/* Fuel type selects */
.fuel-compare {
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  gap: calc(var(--spacing) * 2);
  align-items: center;
}

.vs-badge {
  font-weight: 700;
  color: var(--color-muted);
  font-size: 1rem;
  text-align: center;
}

.fuel-select-group label {
  display: block;
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--color-muted);
  margin-bottom: 4px;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.fuel-select-group select {
  width: 100%;
  padding: 8px 12px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  font-size: 0.95rem;
  background: var(--color-surface);
}

.fuel-select-group.vehicle-a select { border-color: var(--color-ev); }
.fuel-select-group.vehicle-b select { border-color: var(--color-gas); }

/* Form controls */
.form-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: calc(var(--spacing) * 2);
}

.form-group {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.form-group label {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--color-text);
}

.form-group .hint {
  font-size: 0.75rem;
  color: var(--color-muted);
}

.form-group select,
.form-group input[type="number"],
.form-group input[type="text"] {
  padding: 8px 12px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  font-size: 0.95rem;
  background: var(--color-surface);
  transition: border-color 0.15s;
}

.form-group select:focus,
.form-group input:focus {
  outline: none;
  border-color: var(--color-accent);
  box-shadow: 0 0 0 3px rgba(21,101,192,0.1);
}

/* Slider + number input pair */
.range-group {
  display: flex;
  gap: var(--spacing);
  align-items: center;
}

.range-group input[type="range"] {
  flex: 1;
  accent-color: var(--color-accent);
}

.range-group input[type="number"] {
  width: 80px;
  padding: 6px 10px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  font-size: 0.9rem;
  text-align: center;
}

/* Ownership year radios */
.ownership-radios {
  display: flex;
  gap: var(--spacing);
  flex-wrap: wrap;
}

.ownership-radios input[type="radio"] { display: none; }

.ownership-radios label {
  padding: 6px 14px;
  border: 1px solid var(--color-border);
  border-radius: 20px;
  font-size: 0.85rem;
  cursor: pointer;
  transition: background 0.15s, border-color 0.15s;
}

.ownership-radios input[type="radio"]:checked + label {
  background: var(--color-accent);
  border-color: var(--color-accent);
  color: #fff;
  font-weight: 600;
}

/* Price input with source note */
.price-input-row {
  display: flex;
  align-items: baseline;
  gap: var(--spacing);
}

.price-source {
  font-size: 0.72rem;
  color: var(--color-muted);
}

/* Incentive display grid */
.incentive-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: calc(var(--spacing) * 1.5);
}

.incentive-col { display: flex; flex-direction: column; gap: 6px; }
.incentive-col-header {
  font-size: 0.78rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  padding-bottom: 4px;
  border-bottom: 2px solid;
}
.incentive-col-header.col-a { color: var(--color-ev); border-color: var(--color-ev); }
.incentive-col-header.col-b { color: var(--color-gas); border-color: var(--color-gas); }

.incentive-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 0.85rem;
}

.incentive-amount { font-weight: 600; }

/* Advanced section */
.collapsible-trigger {
  width: 100%;
  display: flex;
  align-items: center;
  gap: var(--spacing);
  padding: calc(var(--spacing) * 1.5) 0;
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--color-text);
  cursor: pointer;
  background: none;
  border: none;
  border-top: 1px solid var(--color-border);
}

.collapsible-trigger .chevron {
  transition: transform 0.2s;
  margin-left: auto;
  font-style: normal;
}

.collapsible-trigger[aria-expanded="true"] .chevron { transform: rotate(180deg); }

.collapsible-content {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.3s ease;
}

.collapsible-content.open { max-height: 2000px; }

.advanced-grid {
  display: grid;
  grid-template-columns: 1fr 1fr 1fr;
  gap: calc(var(--spacing) * 2);
  padding: calc(var(--spacing) * 2) 0;
}

.advanced-grid .adv-col-a label { color: var(--color-ev); }
.advanced-grid .adv-col-b label { color: var(--color-gas); }

/* Results section */
#results-section.hidden { display: none; }
#select-prompt.hidden   { display: none; }

.results-header {
  text-align: center;
  margin-bottom: calc(var(--spacing) * 3);
  background: #fff;
  border-radius: var(--radius-lg);
  padding: calc(var(--spacing) * 3);
  box-shadow: var(--shadow);
}

.results-divider {
  display: flex;
  align-items: center;
  gap: calc(var(--spacing) * 2);
  margin-bottom: calc(var(--spacing) * 2);
}

.results-divider::before,
.results-divider::after {
  content: "";
  flex: 1;
  height: 2px;
  background: linear-gradient(90deg, var(--color-border), var(--color-ev), var(--color-gas), var(--color-border));
}

.results-divider span {
  font-weight: 700;
  font-size: 1.8rem !important;
  color: var(--color-muted);
  text-transform: uppercase;
  letter-spacing: 0.1em;
  white-space: nowrap;
}

.results-header p {
  font-size: 1.7rem !important;
  margin: 0 0 calc(var(--spacing) * 0.5) 0;
}

.headline-text {
  font-size: 2.8rem !important;
  font-weight: 700;
  line-height: 1.3;
  margin-top: var(--spacing);
}

.headline-a  { color: var(--color-ev); }
.headline-b  { color: var(--color-gas); }
.headline-neutral { color: var(--color-text); }

/* Result cards grid */
.result-cards {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: calc(var(--spacing) * 2);
  margin-bottom: calc(var(--spacing) * 3);
}

.result-card {
  border: 2px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: calc(var(--spacing) * 2.5);
  background: #fff;
}

.result-card.card-a { border-color: var(--color-ev); }
.result-card.card-b { border-color: var(--color-gas); }

.result-card-header {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  margin-bottom: calc(var(--spacing) * 2);
}

.result-card-fuel-type {
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  padding: 3px 10px;
  border-radius: 12px;
}

.card-a .result-card-fuel-type { background: var(--color-ev-light); color: var(--color-ev); }
.card-b .result-card-fuel-type { background: var(--color-gas-light); color: var(--color-gas); }

.result-total {
  text-align: right;
}

.result-total .label {
  font-size: 0.72rem;
  color: var(--color-muted);
  display: block;
}

.result-total .value {
  font-size: 1.2rem;
  font-weight: 700;
}

.card-a .result-total .value { color: var(--color-ev); }
.card-b .result-total .value { color: var(--color-gas); }

.result-metrics {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--spacing);
}

.metric {
  background: var(--color-bg);
  border-radius: var(--radius);
  padding: var(--spacing) calc(var(--spacing) * 1.5);
}

.metric .metric-label {
  font-size: 0.72rem;
  color: var(--color-muted);
  display: block;
  margin-bottom: 2px;
}

.metric .metric-value {
  font-size: 0.95rem;
  font-weight: 600;
}

/* Breakdown table */
.breakdown-table-wrap {
  overflow-x: auto;
  margin-bottom: calc(var(--spacing) * 3);
}

.breakdown-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.9rem;
}

.breakdown-table th,
.breakdown-table td {
  padding: 10px 14px;
  text-align: right;
  border-bottom: 1px solid var(--color-border);
}

.breakdown-table th:first-child,
.breakdown-table td:first-child { text-align: left; }

.breakdown-table thead th {
  background: var(--color-bg);
  font-weight: 600;
  font-size: 0.82rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.breakdown-table .col-header-a { color: var(--color-ev); }
.breakdown-table .col-header-b { color: var(--color-gas); }

.breakdown-table .total-row td {
  font-weight: 700;
  background: var(--color-bg);
  border-top: 2px solid var(--color-border);
}

.highlight-a { color: var(--color-ev); }
.highlight-b { color: var(--color-gas); }

.diff { font-size: 0.82rem; }
.better-a { color: var(--color-ev); }
.better-b { color: var(--color-gas); }

/* Charts */
.chart-section {
  margin-bottom: calc(var(--spacing) * 3);
}

.chart-title {
  font-size: 0.95rem;
  font-weight: 600;
  margin-bottom: var(--spacing);
  color: var(--color-text);
}

.chart-container {
  position: relative;
  height: 300px;
}

/* Action buttons */
.action-buttons {
  display: flex;
  gap: var(--spacing);
  justify-content: flex-end;
  margin-top: calc(var(--spacing) * 2);
}

.btn {
  padding: 8px 18px;
  border-radius: var(--radius);
  font-size: 0.9rem;
  font-weight: 600;
  cursor: pointer;
  transition: background 0.15s, transform 0.1s;
  border: none;
}

.btn:active { transform: scale(0.97); }

.btn-primary   { background: var(--color-accent); color: #fff; }
.btn-primary:hover { background: #1251a0; }

.btn-secondary {
  background: var(--color-bg);
  color: var(--color-text);
  border: 1px solid var(--color-border);
}
.btn-secondary:hover { background: #e9ecef; }

.btn-outline {
  background: transparent;
  color: var(--color-muted);
  border: 1px solid var(--color-border);
}
.btn-outline:hover { background: var(--color-bg); color: var(--color-text); }

.btn.copied { background: var(--color-ev); color: #fff; }

/* Methodology / FAQ */
.methodology-section {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  margin-bottom: calc(var(--spacing) * 3);
  overflow: hidden;
}

.methodology-body {
  padding: 0 calc(var(--spacing) * 3) calc(var(--spacing) * 3);
}

.methodology-body h3 {
  font-size: 1rem;
  margin: calc(var(--spacing) * 2) 0 var(--spacing);
  color: var(--color-text);
}

.methodology-body p,
.methodology-body li {
  font-size: 0.87rem;
  color: var(--color-muted);
  margin-bottom: 6px;
}

.methodology-body ul {
  padding-left: calc(var(--spacing) * 2);
}

.faq-item { margin-bottom: calc(var(--spacing) * 2); }

/* Yearly cost table */
.yearly-tables {
  padding: calc(var(--spacing) * 2) calc(var(--spacing) * 3) calc(var(--spacing) * 3);
  display: flex;
  flex-direction: column;
  gap: calc(var(--spacing) * 4);
}

.yearly-table-title {
  font-size: 1rem;
  font-weight: 600;
  margin-bottom: var(--spacing);
  color: var(--color-text);
}

.yearly-table-scroll {
  overflow-x: auto;
}

.yearly-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.85rem;
  min-width: 560px;
}

.yearly-table th {
  background: var(--color-bg);
  padding: 7px 12px;
  text-align: right;
  font-weight: 600;
  border-bottom: 2px solid var(--color-border);
  white-space: nowrap;
}

.yearly-table th:first-child { text-align: left; }

.yearly-table td {
  padding: 6px 12px;
  text-align: right;
  border-bottom: 1px solid var(--color-border);
}

.yearly-table td.yr-year { text-align: left; font-weight: 500; white-space: nowrap; }
.yearly-table td.yr-zero { color: var(--color-muted); }
.yearly-table td.yr-credit { color: var(--color-ev); }
.yearly-table td.yr-total { font-weight: 600; }
.yearly-table tr.yr-last td { border-top: 2px solid var(--color-border); background: var(--color-bg); }
.faq-question { font-weight: 600; font-size: 0.9rem; margin-bottom: 4px; }
.faq-answer { font-size: 0.85rem; color: var(--color-muted); }

/* Footer */
.site-footer {
  border-top: 1px solid var(--color-border);
  padding: calc(var(--spacing) * 3) 0;
  margin-top: calc(var(--spacing) * 2);
  background: var(--color-surface);
}

.footer-logos {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-top: 1em;
}

.footer-logo {
  height: 60px;
  width: auto;
}

/* Loading / Error */
#app-loading {
  text-align: center;
  padding: calc(var(--spacing) * 10) 0;
  color: var(--color-muted);
}

#app-loading.hidden { display: none; }
#app-content.hidden { display: none; }

#loading-error {
  background: #fff3cd;
  border: 1px solid #ffc107;
  border-radius: var(--radius);
  padding: calc(var(--spacing) * 2);
  text-align: center;
  color: #856404;
}

#loading-error.hidden { display: none; }

/* Select prompt */
#select-prompt {
  text-align: center;
  padding: calc(var(--spacing) * 4) calc(var(--spacing) * 2);
  color: var(--color-muted);
  font-size: 1rem;
  background: var(--color-surface);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

.select-prompt-icon { font-size: 3rem; margin-bottom: var(--spacing); }

/* Footer */
.site-footer {
  background: var(--color-surface);
  border-top: 1px solid var(--color-border);
  padding: calc(var(--spacing) * 3) 0;
  margin-top: calc(var(--spacing) * 4);
}

.footer-content {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: calc(var(--spacing) * 2);
  font-size: 0.82rem;
  color: var(--color-muted);
}

/* Responsive — mobile (<640px) */
@media (max-width: 640px) {
  .container { padding: 0 var(--spacing); }

  .site-header { padding: var(--spacing) 0; }
  .site-header .container { flex-wrap: nowrap; gap: var(--spacing); }
  .site-tagline { display: none; }
  .brand-wordmark { height: 30px; }
  #btn-reset { margin-left: auto; }
  .site-header .btn { padding: 5px 8px; font-size: 0.72rem; }

  .fuel-compare {
    grid-template-columns: 1fr;
  }
  .vs-badge { display: none; }

  .form-grid { grid-template-columns: 1fr; }
  .incentive-grid { grid-template-columns: 1fr; }
  .result-cards  { grid-template-columns: 1fr; }
  .advanced-grid { grid-template-columns: 1fr 1fr; }

  .category-grid { grid-template-columns: repeat(auto-fill, minmax(120px, 1fr)); }

  .action-buttons { flex-wrap: wrap; }

  .footer-content { flex-direction: column; text-align: center; }
}

/* Print styles */
@media print {
  .site-header,
  #btn-share, #btn-export-pdf, #btn-reset,
  .action-buttons,
  .collapsible-trigger,
  .site-footer { display: none; }

  body { background: white; }
  .card, .result-card { box-shadow: none; border: 1px solid #ccc; }
  .collapsible-content { max-height: none !important; }
}