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

:root {
  --color-bg: #f5f2eb;
  --color-surface: #ffffff;
  --color-surface-alt: #ede8df;
  --color-primary: #2d6a4f;
  --color-primary-light: #40916c;
  --color-primary-dark: #1b4332;
  --color-accent: #d4a24e;
  --color-accent-dark: #b8863a;
  --color-text: #2c2c2c;
  --color-text-muted: #5c5c5c;
  --color-text-light: #7a7a7a;
  --color-border: #d6d0c4;
  --color-border-light: #e8e2d6;
  --color-success: #2d6a4f;
  --color-error: #c44536;
  --shadow-sm: 0 1px 3px rgba(0,0,0,0.08);
  --shadow-md: 0 4px 12px rgba(0,0,0,0.1);
  --shadow-lg: 0 8px 24px rgba(0,0,0,0.12);
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 16px;
  --font-sans: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, sans-serif;
  --font-mono: 'SF Mono', 'Fira Code', 'Cascadia Code', monospace;
  --max-width: 1160px;
  --header-height: 64px;
}

html { scroll-behavior: smooth; font-size: 16px; }
body {
  font-family: var(--font-sans);
  color: var(--color-text);
  background: var(--color-bg);
  line-height: 1.6;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

a { color: var(--color-primary); text-decoration: none; }
a:hover, a:focus-visible { color: var(--color-primary-dark); text-decoration: underline; }

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

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

.skip-link {
  position: absolute;
  top: -100%;
  left: 16px;
  background: var(--color-primary);
  color: #fff;
  padding: 8px 16px;
  border-radius: var(--radius-sm);
  z-index: 1000;
  font-weight: 600;
}
.skip-link:focus { top: 8px; color: #fff; }

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

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: var(--header-height);
}

.logo {
  display: flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
  color: var(--color-text);
}
.logo:hover, .logo:focus-visible { text-decoration: none; color: var(--color-text); }

.logo-text {
  font-size: 1.25rem;
  font-weight: 700;
  letter-spacing: -0.02em;
}
.logo-accent { color: var(--color-primary-light); }

.main-nav ul {
  display: flex;
  list-style: none;
  gap: 24px;
}
.main-nav a {
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--color-text-muted);
  padding: 4px 0;
  border-bottom: 2px solid transparent;
  transition: color 0.15s, border-color 0.15s;
}
.main-nav a:hover, .main-nav a:focus-visible {
  color: var(--color-primary);
  border-bottom-color: var(--color-primary);
  text-decoration: none;
}

/* ===== Hero ===== */
.hero-section {
  background: linear-gradient(135deg, var(--color-primary-dark) 0%, var(--color-primary) 60%, var(--color-primary-light) 100%);
  color: #fff;
  padding: 60px 0 56px;
}
.hero-content { max-width: 680px; }
.hero-content h1 {
  font-size: clamp(1.75rem, 4vw, 2.5rem);
  font-weight: 800;
  line-height: 1.2;
  margin-bottom: 16px;
  letter-spacing: -0.02em;
}
.hero-sub {
  font-size: 1.1rem;
  opacity: 0.9;
  line-height: 1.5;
}

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

.calc-layout {
  display: grid;
  grid-template-columns: 1fr 340px;
  gap: 32px;
  align-items: start;
}

.calc-inputs h2,
.calc-results h2 {
  font-size: 1.25rem;
  font-weight: 700;
  margin-bottom: 20px;
  color: var(--color-primary-dark);
}

.input-group {
  margin-bottom: 28px;
}

.input-group label {
  display: block;
  font-weight: 600;
  font-size: 0.95rem;
  margin-bottom: 8px;
  color: var(--color-text);
}

.number-input {
  display: flex;
  align-items: center;
  background: var(--color-surface);
  border: 2px solid var(--color-border);
  border-radius: var(--radius-sm);
  overflow: hidden;
  width: 160px;
  transition: border-color 0.15s;
}
.number-input:focus-within {
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px rgba(45, 106, 79, 0.15);
}
.number-input input {
  border: none;
  background: transparent;
  font-size: 1.1rem;
  font-weight: 600;
  padding: 10px 12px;
  width: 100%;
  color: var(--color-text);
  -moz-appearance: textfield;
}
.number-input input::-webkit-outer-spin-button,
.number-input input::-webkit-inner-spin-button { -webkit-appearance: none; margin: 0; }
.number-input input:focus { outline: none; }

.unit {
  padding: 10px 12px 10px 0;
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--color-text-muted);
  white-space: nowrap;
}

.presets {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  margin-top: 10px;
}

.preset-btn {
  padding: 6px 14px;
  border: 1.5px solid var(--color-border);
  border-radius: 20px;
  background: var(--color-surface);
  font-size: 0.82rem;
  font-weight: 500;
  color: var(--color-text-muted);
  cursor: pointer;
  transition: all 0.15s;
}
.preset-btn:hover {
  border-color: var(--color-primary-light);
  color: var(--color-primary);
}
.preset-btn.active {
  background: var(--color-primary);
  border-color: var(--color-primary);
  color: #fff;
}

.help-text {
  font-size: 0.82rem;
  color: var(--color-text-light);
  margin-top: 8px;
  line-height: 1.5;
}
.help-text a { text-decoration: underline; }

/* ===== Results Panel ===== */
.calc-results {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: 28px;
  box-shadow: var(--shadow-md);
}

.results-sticky {
  position: sticky;
  top: calc(var(--header-height) + 24px);
}

.result-primary {
  text-align: center;
  padding: 20px 0 24px;
  border-bottom: 1px solid var(--color-border-light);
  margin-bottom: 20px;
}

.result-number {
  display: block;
  font-size: 3rem;
  font-weight: 800;
  color: var(--color-primary);
  line-height: 1;
  letter-spacing: -0.03em;
}

.result-label {
  display: block;
  font-size: 0.9rem;
  color: var(--color-text-muted);
  margin-top: 6px;
  font-weight: 500;
}

.result-secondary {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
  margin-bottom: 20px;
}

.result-item {
  background: var(--color-surface-alt);
  border-radius: var(--radius-sm);
  padding: 12px;
  text-align: center;
}

.result-item-label {
  display: block;
  font-size: 0.72rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--color-text-light);
  margin-bottom: 4px;
}

.result-item-value {
  display: block;
  font-size: 1rem;
  font-weight: 700;
  color: var(--color-text);
}

.result-actions {
  display: flex;
  gap: 8px;
  margin-bottom: 16px;
}

.result-note {
  font-size: 0.78rem;
  color: var(--color-text-light);
  line-height: 1.5;
  padding-top: 12px;
  border-top: 1px solid var(--color-border-light);
}

/* ===== Buttons ===== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 10px 20px;
  border-radius: var(--radius-sm);
  font-size: 0.88rem;
  font-weight: 600;
  cursor: pointer;
  border: none;
  transition: all 0.15s;
  font-family: var(--font-sans);
}

.btn-primary {
  background: var(--color-primary);
  color: #fff;
}
.btn-primary:hover { background: var(--color-primary-dark); color: #fff; text-decoration: none; }

.btn-secondary {
  background: var(--color-surface-alt);
  color: var(--color-text);
  border: 1.5px solid var(--color-border);
  flex: 1;
  padding: 8px 12px;
  font-size: 0.82rem;
}
.btn-secondary:hover {
  background: var(--color-border-light);
  border-color: var(--color-primary-light);
  text-decoration: none;
}

.btn-small {
  padding: 8px 16px;
  font-size: 0.82rem;
  background: var(--color-primary);
  color: #fff;
  margin-top: 12px;
}
.btn-small:hover { background: var(--color-primary-dark); color: #fff; text-decoration: none; }

/* ===== Saved Configs ===== */
.saved-configs {
  margin-top: 32px;
  padding-top: 24px;
  border-top: 1px solid var(--color-border-light);
}
.saved-configs h3 {
  font-size: 0.95rem;
  font-weight: 600;
  margin-bottom: 12px;
}
.saved-list {
  margin-bottom: 12px;
}
.saved-item {
  display: flex;
  align-items: center;
  justify-content: space-between;
  background: var(--color-surface-alt);
  border-radius: var(--radius-sm);
  padding: 10px 14px;
  margin-bottom: 8px;
  font-size: 0.85rem;
}
.saved-item-info { flex: 1; }
.saved-item-name { font-weight: 600; color: var(--color-text); }
.saved-item-detail { color: var(--color-text-light); font-size: 0.78rem; }
.saved-item-kwh {
  font-weight: 700;
  color: var(--color-primary);
  margin: 0 12px;
  white-space: nowrap;
}
.saved-item-actions { display: flex; gap: 4px; }
.saved-item-actions button {
  background: none;
  border: 1px solid var(--color-border);
  border-radius: 4px;
  padding: 4px 8px;
  font-size: 0.75rem;
  cursor: pointer;
  color: var(--color-text-muted);
  font-family: var(--font-sans);
}
.saved-item-actions button:hover {
  background: var(--color-border-light);
  color: var(--color-text);
}
.empty-state {
  color: var(--color-text-light);
  font-size: 0.85rem;
  font-style: italic;
}

/* ===== Comparison Table ===== */
.comparison-section {
  padding: 48px 0;
  background: var(--color-surface);
  border-top: 1px solid var(--color-border);
}

.comparison-section h2,
.scenarios-section h2,
.info-section h2,
.why-section h2 {
  font-size: 1.4rem;
  font-weight: 700;
  color: var(--color-primary-dark);
  margin-bottom: 12px;
}

.section-intro {
  color: var(--color-text-muted);
  font-size: 0.95rem;
  margin-bottom: 24px;
  max-width: 640px;
}

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

.comparison-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.88rem;
}

.comparison-table thead {
  background: var(--color-primary-dark);
  color: #fff;
}

.comparison-table th {
  padding: 12px 16px;
  text-align: left;
  font-weight: 600;
  font-size: 0.82rem;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  white-space: nowrap;
}

.comparison-table td {
  padding: 11px 16px;
  border-bottom: 1px solid var(--color-border-light);
  color: var(--color-text);
}

.comparison-table tbody tr:nth-child(even) {
  background: var(--color-surface-alt);
}

.comparison-table tbody tr:hover {
  background: #e8f0ec;
}

.comparison-table td:last-child {
  font-weight: 600;
  color: var(--color-primary);
}

.comparison-note {
  margin-top: 12px;
  font-size: 0.82rem;
  color: var(--color-text-light);
}

/* ===== Scenarios ===== */
.scenarios-section {
  padding: 48px 0;
}

.scenario-cards {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
}

.scenario-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 24px;
  box-shadow: var(--shadow-sm);
  transition: box-shadow 0.15s;
}
.scenario-card:hover { box-shadow: var(--shadow-md); }

.scenario-card h3 {
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--color-primary-dark);
  margin-bottom: 12px;
}

.scenario-card dl {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 4px 12px;
  font-size: 0.85rem;
  margin-bottom: 12px;
}
.scenario-card dt { color: var(--color-text-light); }
.scenario-card dd { font-weight: 600; color: var(--color-text); }

.scenario-output {
  font-size: 1.3rem;
  font-weight: 800;
  color: var(--color-primary);
  margin-bottom: 8px;
}

.scenario-desc {
  font-size: 0.85rem;
  color: var(--color-text-muted);
  line-height: 1.5;
}

/* ===== Info Section ===== */
.info-section {
  padding: 48px 0;
  background: var(--color-surface);
  border-top: 1px solid var(--color-border);
}

.info-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 32px;
}

.info-block {
  margin-bottom: 32px;
}

.info-block p {
  font-size: 0.9rem;
  color: var(--color-text-muted);
  line-height: 1.65;
  margin-bottom: 12px;
}

.formula {
  background: var(--color-surface-alt);
  border-left: 4px solid var(--color-primary);
  padding: 16px 20px;
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  margin: 16px 0;
  font-size: 0.9rem;
}

.formula p { margin-bottom: 4px; }

.mistake-list {
  list-style: none;
  padding: 0;
}
.mistake-list li {
  padding: 10px 0 10px 28px;
  position: relative;
  font-size: 0.9rem;
  color: var(--color-text-muted);
  line-height: 1.6;
  border-bottom: 1px solid var(--color-border-light);
}
.mistake-list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 14px;
  width: 16px;
  height: 16px;
  background: var(--color-error);
  border-radius: 50%;
  opacity: 0.85;
}
.mistake-list li::after {
  content: "!";
  position: absolute;
  left: 5px;
  top: 10px;
  color: #fff;
  font-size: 0.7rem;
  font-weight: 800;
}

.faq-list dt {
  font-weight: 600;
  font-size: 0.92rem;
  color: var(--color-text);
  margin-top: 16px;
  margin-bottom: 4px;
}
.faq-list dd {
  font-size: 0.88rem;
  color: var(--color-text-muted);
  line-height: 1.6;
  padding-left: 0;
}

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

.why-content {
  max-width: 720px;
}
.why-content p {
  font-size: 0.92rem;
  color: var(--color-text-muted);
  line-height: 1.65;
  margin-bottom: 12px;
}

.version-note {
  font-size: 0.78rem;
  color: var(--color-text-light);
  margin-top: 16px;
  padding-top: 12px;
  border-top: 1px solid var(--color-border-light);
}

/* ===== Footer ===== */
.site-footer {
  margin-top: auto;
  background: var(--color-primary-dark);
  color: rgba(255,255,255,0.7);
  padding: 24px 0;
  font-size: 0.82rem;
}

.footer-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 12px;
}

.footer-links {
  display: flex;
  gap: 20px;
}
.footer-links a {
  color: rgba(255,255,255,0.7);
  text-decoration: none;
}
.footer-links a:hover { color: #fff; text-decoration: underline; }

.footer-note a {
  color: rgba(255,255,255,0.85);
  text-decoration: underline;
}
.footer-note a:hover { color: #fff; }

/* ===== Toast ===== */
.toast {
  position: fixed;
  bottom: 24px;
  right: 24px;
  background: var(--color-primary-dark);
  color: #fff;
  padding: 12px 20px;
  border-radius: var(--radius-sm);
  font-size: 0.85rem;
  font-weight: 500;
  box-shadow: var(--shadow-lg);
  z-index: 1000;
  opacity: 0;
  transform: translateY(8px);
  transition: opacity 0.2s, transform 0.2s;
  pointer-events: none;
}
.toast.show {
  opacity: 1;
  transform: translateY(0);
}

/* ===== Print ===== */
@media print {
  .site-header, .site-footer, .result-actions, .saved-configs, .presets, .btn, .skip-link { display: none !important; }
  .calc-layout { display: block; }
  .calc-results { border: none; box-shadow: none; padding: 0; }
  .results-sticky { position: static; }
  body { background: #fff; }
}

/* ===== Responsive ===== */
@media (max-width: 900px) {
  .calc-layout { grid-template-columns: 1fr; }
  .results-sticky { position: static; }
  .scenario-cards { grid-template-columns: 1fr; }
  .info-grid { grid-template-columns: 1fr; }
}

@media (max-width: 600px) {
  .hero-section { padding: 40px 0 36px; }
  .hero-content h1 { font-size: 1.5rem; }
  .result-number { font-size: 2.4rem; }
  .result-secondary { grid-template-columns: 1fr 1fr; }
  .comparison-table { font-size: 0.8rem; }
  .comparison-table th, .comparison-table td { padding: 8px 10px; }
  .footer-inner { flex-direction: column; align-items: flex-start; }
  .main-nav ul { gap: 14px; }
  .main-nav a { font-size: 0.82rem; }
}

@media (max-width: 400px) {
  .number-input { width: 100%; }
  .result-secondary { grid-template-columns: 1fr; }
  .result-actions { flex-direction: column; }
}



/* 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;
}