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

:root {
  --color-bg: #1a1612;
  --color-bg-card: #231e18;
  --color-bg-card-alt: #2a241e;
  --color-surface: #332d24;
  --color-border: #4a4035;
  --color-border-light: #3a3228;
  --color-text: #e8e0d4;
  --color-text-muted: #a09484;
  --color-text-dim: #7a6e60;
  --color-accent: #c8a45e;
  --color-accent-hover: #d9b86e;
  --color-accent-dim: #8a6e30;
  --color-success: #6aab6a;
  --color-danger: #c96060;
  --color-focus: #c8a45e;
  --font-body: 'Georgia', 'Times New Roman', serif;
  --font-heading: 'Georgia', 'Times New Roman', serif;
  --font-mono: 'Courier New', Courier, monospace;
  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 12px;
  --shadow-sm: 0 1px 3px rgba(0,0,0,0.3);
  --shadow-md: 0 4px 12px rgba(0,0,0,0.4);
  --shadow-lg: 0 8px 24px rgba(0,0,0,0.5);
  --transition: 0.2s ease;
  --max-width: 1200px;
}

html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

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

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

a:hover {
  color: var(--color-accent-hover);
}

a:focus-visible {
  outline: 2px solid var(--color-focus);
  outline-offset: 2px;
  border-radius: 2px;
}

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

/* ===== Accessibility ===== */
.skip-link {
  position: absolute;
  top: -100%;
  left: 16px;
  background: var(--color-accent);
  color: var(--color-bg);
  padding: 8px 16px;
  border-radius: var(--radius-sm);
  z-index: 1000;
  font-weight: bold;
}

.skip-link:focus {
  top: 16px;
}

/* ===== Layout ===== */
.container {
  width: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 20px;
}

/* ===== Header ===== */
.site-header {
  background: var(--color-bg-card);
  border-bottom: 1px solid var(--color-border);
  padding: 12px 0;
  position: sticky;
  top: 0;
  z-index: 100;
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}

.logo {
  display: flex;
  align-items: center;
  gap: 8px;
  color: var(--color-accent);
  font-weight: bold;
  font-size: 1.25rem;
  font-family: var(--font-heading);
}

.logo:hover {
  color: var(--color-accent-hover);
}

.logo-icon {
  flex-shrink: 0;
}

.main-nav ul {
  display: flex;
  list-style: none;
  gap: 24px;
}

.main-nav a {
  color: var(--color-text-muted);
  font-size: 0.95rem;
  padding: 4px 0;
  border-bottom: 2px solid transparent;
  transition: color var(--transition), border-color var(--transition);
}

.main-nav a:hover,
.main-nav a[aria-current="page"] {
  color: var(--color-accent);
  border-bottom-color: var(--color-accent);
}

/* ===== Hero ===== */
.hero-section {
  padding: 48px 0 32px;
  text-align: center;
}

.hero-content h1 {
  font-family: var(--font-heading);
  font-size: 2.5rem;
  color: var(--color-accent);
  margin-bottom: 12px;
  line-height: 1.2;
}

.hero-subtitle {
  font-size: 1.15rem;
  color: var(--color-text-muted);
  max-width: 600px;
  margin: 0 auto;
}

/* ===== Section Headings ===== */
.section-heading {
  font-family: var(--font-heading);
  font-size: 1.75rem;
  color: var(--color-accent);
  margin-bottom: 8px;
}

.section-intro {
  color: var(--color-text-muted);
  margin-bottom: 24px;
  max-width: 700px;
}

/* ===== Calculator Section ===== */
.calculator-section {
  padding: 24px 0 48px;
}

.calc-layout {
  display: grid;
  grid-template-columns: 1fr 320px;
  gap: 24px;
  align-items: start;
}

.calc-main {
  display: flex;
  flex-direction: column;
  gap: 24px;
}

.calc-card {
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: 24px;
}

/* ===== Mode Toggle ===== */
.mode-toggle {
  display: flex;
  background: var(--color-surface);
  border-radius: var(--radius-md);
  padding: 4px;
  margin-bottom: 24px;
  width: fit-content;
}

.mode-btn {
  background: transparent;
  border: none;
  color: var(--color-text-muted);
  padding: 8px 20px;
  border-radius: var(--radius-sm);
  cursor: pointer;
  font-family: var(--font-body);
  font-size: 0.95rem;
  transition: all var(--transition);
}

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

.mode-btn.active {
  background: var(--color-accent);
  color: var(--color-bg);
  font-weight: bold;
}

/* ===== Form Elements ===== */
.input-group {
  margin-bottom: 20px;
}

.input-label {
  display: block;
  font-weight: bold;
  color: var(--color-text);
  margin-bottom: 6px;
  font-size: 0.95rem;
}

.input-hint {
  font-size: 0.85rem;
  color: var(--color-text-dim);
  margin-top: 4px;
}

.input-row {
  display: flex;
  gap: 8px;
}

.calc-input {
  flex: 1;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  color: var(--color-text);
  padding: 10px 14px;
  border-radius: var(--radius-sm);
  font-family: var(--font-body);
  font-size: 1rem;
  transition: border-color var(--transition);
}

.calc-input:focus {
  outline: none;
  border-color: var(--color-accent);
  box-shadow: 0 0 0 2px rgba(200, 164, 94, 0.2);
}

.calc-select {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  color: var(--color-text);
  padding: 10px 14px;
  border-radius: var(--radius-sm);
  font-family: var(--font-body);
  font-size: 1rem;
  cursor: pointer;
  transition: border-color var(--transition);
}

.calc-select:focus {
  outline: none;
  border-color: var(--color-accent);
  box-shadow: 0 0 0 2px rgba(200, 164, 94, 0.2);
}

.calc-select.full-width {
  width: 100%;
}

.calc-input.full-width {
  width: 100%;
}

/* ===== Custom Scale Panel ===== */
.custom-scale-panel {
  background: var(--color-bg-card-alt);
  border: 1px solid var(--color-border-light);
  border-radius: var(--radius-md);
  padding: 16px;
  margin-bottom: 20px;
}

.custom-scale-panel.hidden {
  display: none;
}

/* ===== Buttons ===== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 10px 20px;
  border: none;
  border-radius: var(--radius-sm);
  font-family: var(--font-body);
  font-size: 0.95rem;
  cursor: pointer;
  transition: all var(--transition);
  font-weight: bold;
}

.btn-primary {
  background: var(--color-accent);
  color: var(--color-bg);
}

.btn-primary:hover {
  background: var(--color-accent-hover);
}

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

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

.btn-small {
  padding: 6px 14px;
  font-size: 0.85rem;
}

.btn-danger {
  background: transparent;
  color: var(--color-danger);
  border: 1px solid var(--color-danger);
}

.btn-danger:hover {
  background: var(--color-danger);
  color: var(--color-bg);
}

/* ===== Results ===== */
.results-panel {
  background: var(--color-bg-card-alt);
  border: 1px solid var(--color-accent-dim);
  border-radius: var(--radius-md);
  padding: 20px;
  margin-top: 8px;
}

.results-heading {
  font-family: var(--font-heading);
  font-size: 1.1rem;
  color: var(--color-accent);
  margin-bottom: 12px;
}

.results-output {
  display: flex;
  flex-direction: column;
  gap: 8px;
  margin-bottom: 16px;
}

.result-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 8px 0;
  border-bottom: 1px solid var(--color-border-light);
}

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

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

.result-value {
  font-weight: bold;
  color: var(--color-text);
  font-size: 1.1rem;
  font-family: var(--font-mono);
}

.result-actions {
  display: flex;
  gap: 8px;
}

/* ===== Travel Card ===== */
.travel-card .card-heading {
  font-family: var(--font-heading);
  font-size: 1.2rem;
  color: var(--color-accent);
  margin-bottom: 8px;
}

.travel-card .card-note {
  color: var(--color-text-muted);
  font-size: 0.9rem;
  margin-bottom: 16px;
}

.travel-grid {
  display: grid;
  grid-template-columns: 1fr auto auto;
  gap: 0;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  overflow: hidden;
}

.travel-header {
  display: contents;
}

.travel-header span {
  background: var(--color-surface);
  padding: 10px 14px;
  font-weight: bold;
  font-size: 0.85rem;
  color: var(--color-text-muted);
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.travel-row {
  display: contents;
}

.travel-row .travel-mode {
  padding: 10px 14px;
  border-top: 1px solid var(--color-border-light);
}

.travel-row span {
  padding: 10px 14px;
  border-top: 1px solid var(--color-border-light);
  font-size: 0.95rem;
}

.travel-footnote {
  font-size: 0.85rem;
  color: var(--color-text-dim);
  margin-top: 12px;
  font-style: italic;
}

/* ===== Sidebar ===== */
.calc-sidebar {
  display: flex;
  flex-direction: column;
  gap: 20px;
  position: sticky;
  top: 80px;
}

.sidebar-card {
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: 20px;
}

.sidebar-heading {
  font-family: var(--font-heading);
  font-size: 1.1rem;
  color: var(--color-accent);
  margin-bottom: 12px;
}

.presets-list,
.history-list {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.preset-item,
.history-item {
  background: var(--color-surface);
  border: 1px solid var(--color-border-light);
  border-radius: var(--radius-sm);
  padding: 10px 12px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 8px;
}

.preset-name {
  font-weight: bold;
  font-size: 0.9rem;
  color: var(--color-text);
}

.preset-detail {
  font-size: 0.8rem;
  color: var(--color-text-dim);
}

.preset-use {
  background: transparent;
  border: 1px solid var(--color-accent-dim);
  color: var(--color-accent);
  padding: 4px 10px;
  border-radius: var(--radius-sm);
  cursor: pointer;
  font-size: 0.8rem;
  font-family: var(--font-body);
  transition: all var(--transition);
}

.preset-use:hover {
  background: var(--color-accent);
  color: var(--color-bg);
}

.preset-delete {
  background: transparent;
  border: none;
  color: var(--color-danger);
  cursor: pointer;
  font-size: 1.1rem;
  padding: 2px 6px;
  border-radius: var(--radius-sm);
  line-height: 1;
}

.preset-delete:hover {
  background: rgba(201, 96, 96, 0.15);
}

.history-item {
  font-size: 0.85rem;
}

.history-from {
  color: var(--color-text);
}

.history-to {
  color: var(--color-accent);
  font-weight: bold;
}

.history-time {
  color: var(--color-text-dim);
  font-size: 0.75rem;
}

.empty-state {
  color: var(--color-text-dim);
  font-size: 0.9rem;
  font-style: italic;
  text-align: center;
  padding: 12px 0;
}

/* ===== Reference Section ===== */
.reference-section {
  padding: 48px 0;
  background: var(--color-bg-card);
  border-top: 1px solid var(--color-border);
}

.table-wrapper {
  overflow-x: auto;
  border-radius: var(--radius-md);
  border: 1px solid var(--color-border);
}

.reference-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.95rem;
}

.reference-table th {
  background: var(--color-surface);
  color: var(--color-accent);
  padding: 12px 16px;
  text-align: left;
  font-weight: bold;
  font-family: var(--font-heading);
  white-space: nowrap;
}

.reference-table td {
  padding: 12px 16px;
  border-top: 1px solid var(--color-border-light);
  color: var(--color-text);
}

.reference-table tr:hover td {
  background: var(--color-bg-card-alt);
}

/* ===== Guide Section ===== */
.guide-section {
  padding: 48px 0;
}

.guide-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 20px;
}

.guide-card {
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: 24px;
}

.guide-card h3 {
  font-family: var(--font-heading);
  color: var(--color-accent);
  font-size: 1.1rem;
  margin-bottom: 10px;
}

.guide-card p {
  color: var(--color-text-muted);
  font-size: 0.95rem;
  line-height: 1.7;
}

/* ===== Why Section ===== */
.why-section {
  padding: 48px 0;
  background: var(--color-bg-card);
  border-top: 1px solid var(--color-border);
}

.why-content {
  max-width: 800px;
}

.why-content p {
  color: var(--color-text-muted);
  font-size: 1.05rem;
  line-height: 1.8;
  margin-bottom: 16px;
}

.why-content p:last-child {
  margin-bottom: 0;
}

/* ===== Footer ===== */
.site-footer {
  margin-top: auto;
  background: var(--color-bg-card);
  border-top: 1px solid var(--color-border);
  padding: 24px 0;
}

.footer-inner {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 16px;
}

.footer-brand {
  display: flex;
  align-items: center;
  gap: 12px;
}

.footer-logo {
  font-weight: bold;
  color: var(--color-accent);
  font-family: var(--font-heading);
}

.footer-version {
  color: var(--color-text-dim);
  font-size: 0.85rem;
}

.footer-nav ul {
  display: flex;
  list-style: none;
  gap: 20px;
}

.footer-nav a {
  color: var(--color-text-muted);
  font-size: 0.9rem;
}

.footer-nav a:hover {
  color: var(--color-accent);
}

/* ===== Utility ===== */
.hidden {
  display: none !important;
}

/* ===== Responsive ===== */
@media (max-width: 900px) {
  .calc-layout {
    grid-template-columns: 1fr;
  }

  .calc-sidebar {
    position: static;
    flex-direction: row;
    flex-wrap: wrap;
  }

  .sidebar-card {
    flex: 1;
    min-width: 250px;
  }

  .hero-content h1 {
    font-size: 2rem;
  }
}

@media (max-width: 600px) {
  .container {
    padding: 0 16px;
  }

  .hero-section {
    padding: 32px 0 24px;
  }

  .hero-content h1 {
    font-size: 1.6rem;
  }

  .hero-subtitle {
    font-size: 1rem;
  }

  .calc-card {
    padding: 16px;
  }

  .input-row {
    flex-direction: column;
  }

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

  .travel-header span {
    display: none;
  }

  .travel-row {
    display: flex;
    flex-direction: column;
    padding: 10px 14px;
    border-top: 1px solid var(--color-border-light);
  }

  .travel-row span {
    border-top: none;
    padding: 2px 0;
  }

  .travel-row .travel-mode {
    font-weight: bold;
    padding-bottom: 6px;
  }

  .sidebar-card {
    min-width: 100%;
  }

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

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

  .footer-nav ul {
    flex-wrap: wrap;
    justify-content: center;
  }

  .main-nav ul {
    gap: 16px;
  }
}

/* ===== Print Styles ===== */
@media print {
  .site-header,
  .site-footer,
  .calc-sidebar,
  .result-actions,
  .mode-toggle,
  .btn {
    display: none !important;
  }

  body {
    background: white;
    color: black;
  }

  .calc-card,
  .results-panel {
    border: 1px solid #ccc;
    background: white;
  }

  .result-value {
    color: black;
  }
}



/* Factory-injected deployment helpers. The AI owns the site design above this block. */
.ad-unit {
  width: min(100%, 720px);
  min-height: 120px;
  margin: 24px auto;
  display: block;
}

.legal-page {
  width: min(900px, calc(100% - 32px));
  margin: 40px auto;
}

.factory-fallback-nav {
  width: min(900px, calc(100% - 32px));
  margin: 24px auto 0;
  display: flex;
  flex-wrap: wrap;
  gap: 10px 16px;
  align-items: center;
  font-size: 0.95rem;
}

.factory-fallback-nav a {
  color: inherit;
  text-decoration: none;
  border-bottom: 1px solid currentColor;
}