:root {
  --bg-primary: #0b0f17;
  --bg-secondary: #111827;
  --bg-card: #1f2937;
  --bg-card-hover: #283548;
  --bg-input: #0f172a;
  --border-color: #374151;
  --border-focus: #f59e0b;
  --text-primary: #f9fafb;
  --text-secondary: #9ca3af;
  --text-muted: #6b7280;
  --accent: #f59e0b;
  --accent-hover: #d97706;
  --accent-light: rgba(245, 158, 11, 0.12);
  --cyan: #38bdf8;
  --cyan-light: rgba(56, 189, 248, 0.12);
  --success: #10b981;
  --shadow: 0 10px 25px -5px rgba(0, 0, 0, 0.5), 0 8px 10px -6px rgba(0, 0, 0, 0.4);
  --radius: 12px;
  --radius-sm: 8px;
  --font: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}

[data-theme="light"] {
  --bg-primary: #f8fafc;
  --bg-secondary: #ffffff;
  --bg-card: #ffffff;
  --bg-card-hover: #f1f5f9;
  --bg-input: #f8fafc;
  --border-color: #e2e8f0;
  --border-focus: #d97706;
  --text-primary: #0f172a;
  --text-secondary: #475569;
  --text-muted: #94a3b8;
  --accent: #d97706;
  --accent-hover: #b45309;
  --accent-light: rgba(217, 119, 6, 0.1);
  --cyan: #0284c7;
  --cyan-light: rgba(2, 132, 199, 0.1);
  --shadow: 0 10px 25px -5px rgba(0, 0, 0, 0.08), 0 8px 10px -6px rgba(0, 0, 0, 0.04);
}

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  font-family: var(--font);
  background-color: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.6;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  transition: background-color 0.2s, color 0.2s;
}

.container {
  max-width: 1024px;
  margin: 0 auto;
  padding: 0 16px;
  width: 100%;
}

/* Header */
header {
  padding: 18px 0 14px;
  border-bottom: 1px solid var(--border-color);
  background: var(--bg-secondary);
}

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

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

.brand-icon {
  width: 42px;
  height: 42px;
  border-radius: 10px;
}

.brand-title {
  font-size: 1.35rem;
  font-weight: 800;
  color: var(--text-primary);
  line-height: 1.2;
}

.brand-badge {
  font-size: 0.7rem;
  background: var(--accent-light);
  color: var(--accent);
  padding: 2px 8px;
  border-radius: 20px;
  font-weight: 700;
  vertical-align: middle;
  margin-left: 6px;
}

.back-link {
  color: var(--text-muted);
  text-decoration: none;
  font-size: 0.85rem;
  transition: color 0.2s;
}
.back-link:hover {
  color: var(--accent);
}

.theme-toggle-btn {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  color: var(--text-secondary);
  width: 38px;
  height: 38px;
  border-radius: 50%;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.1rem;
  transition: all 0.2s;
}
.theme-toggle-btn:hover {
  border-color: var(--accent);
  color: var(--accent);
}

/* Presets Bar */
.presets-bar {
  margin: 20px 0;
  display: flex;
  align-items: center;
  gap: 10px;
  flex-wrap: wrap;
}

.presets-label {
  font-size: 0.85rem;
  color: var(--text-muted);
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.preset-chip {
  padding: 8px 14px;
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  color: var(--text-secondary);
  border-radius: 24px;
  font-size: 0.85rem;
  font-weight: 600;
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 6px;
  transition: all 0.2s;
}
.preset-chip:hover {
  border-color: var(--accent);
  color: var(--accent);
  background: var(--accent-light);
}

/* Main Grid */
.calc-grid {
  display: grid;
  grid-template-columns: 1.1fr 0.9fr;
  gap: 24px;
  margin-bottom: 32px;
}

@media (max-width: 860px) {
  .calc-grid {
    grid-template-columns: 1fr;
  }
}

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

.card-title {
  font-size: 1.15rem;
  font-weight: 800;
  margin-bottom: 18px;
  display: flex;
  align-items: center;
  gap: 8px;
  color: var(--text-primary);
}

/* Appliance List */
.appliances-list {
  display: flex;
  flex-direction: column;
  gap: 12px;
  margin-bottom: 24px;
}

.appliance-item {
  background: var(--bg-input);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  padding: 12px 14px;
  display: flex;
  flex-direction: column;
  gap: 10px;
  transition: border-color 0.2s;
}
.appliance-item.active {
  border-color: rgba(245, 158, 11, 0.4);
}

.appliance-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.appliance-check-label {
  display: flex;
  align-items: center;
  gap: 10px;
  cursor: pointer;
  font-weight: 600;
  font-size: 0.95rem;
}
.appliance-check-label input[type="checkbox"] {
  width: 18px;
  height: 18px;
  accent-color: var(--accent);
  cursor: pointer;
}

.appliance-power {
  font-size: 0.8rem;
  color: var(--text-muted);
  font-weight: 600;
  background: var(--bg-card);
  padding: 2px 8px;
  border-radius: 12px;
  border: 1px solid var(--border-color);
}

.appliance-controls {
  display: flex;
  align-items: center;
  gap: 12px;
  padding-left: 28px;
}

.appliance-slider {
  flex: 1;
  height: 6px;
  accent-color: var(--accent);
  cursor: pointer;
}

.appliance-hours-val {
  font-size: 0.88rem;
  font-weight: 700;
  color: var(--text-primary);
  min-width: 60px;
  text-align: right;
}

.appliance-subtotal {
  font-size: 0.8rem;
  color: var(--accent);
  font-weight: 700;
  min-width: 65px;
  text-align: right;
}

/* Global Config Selectors */
.config-group {
  margin-top: 20px;
  padding-top: 18px;
  border-top: 1px solid var(--border-color);
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 14px;
}

@media (max-width: 500px) {
  .config-group {
    grid-template-columns: 1fr;
  }
}

.field-label {
  font-size: 0.82rem;
  font-weight: 700;
  color: var(--text-secondary);
  margin-bottom: 6px;
  display: block;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.field-select {
  width: 100%;
  padding: 10px 12px;
  background: var(--bg-input);
  border: 1px solid var(--border-color);
  color: var(--text-primary);
  font-size: 0.92rem;
  border-radius: var(--radius-sm);
  cursor: pointer;
}
.field-select:focus {
  outline: none;
  border-color: var(--border-focus);
}

/* Results Section */
.results-hero {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
  margin-bottom: 20px;
}

.hero-box {
  background: var(--bg-input);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  padding: 16px 12px;
  text-align: center;
}

.hero-num {
  font-size: 1.6rem;
  font-weight: 800;
  color: var(--accent);
  line-height: 1.1;
}
.hero-num.cyan {
  color: var(--cyan);
}

.hero-desc {
  font-size: 0.75rem;
  color: var(--text-muted);
  text-transform: uppercase;
  font-weight: 700;
  margin-top: 4px;
}

/* Specs Details */
.specs-list {
  display: flex;
  flex-direction: column;
  gap: 10px;
  margin-bottom: 24px;
}

.spec-item {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 12px 14px;
  background: var(--bg-input);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
}

.spec-left {
  display: flex;
  align-items: center;
  gap: 10px;
}

.spec-icon {
  font-size: 1.3rem;
}

.spec-title {
  font-size: 0.92rem;
  font-weight: 700;
  color: var(--text-primary);
}

.spec-sub {
  font-size: 0.75rem;
  color: var(--text-muted);
}

.spec-right {
  text-align: right;
}

.spec-val {
  font-size: 1.2rem;
  font-weight: 800;
  color: var(--text-primary);
}

.spec-unit {
  font-size: 0.75rem;
  color: var(--text-muted);
}

/* Action Toolbar */
.action-toolbar {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
}

.btn-primary {
  flex: 1;
  padding: 12px 16px;
  background: var(--accent);
  color: #000;
  border: none;
  font-weight: 700;
  font-size: 0.95rem;
  border-radius: var(--radius-sm);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  transition: all 0.2s;
  box-shadow: 0 4px 12px rgba(245, 158, 11, 0.25);
}
.btn-primary:hover {
  background: var(--accent-hover);
  color: #fff;
}

.btn-secondary {
  padding: 12px 16px;
  background: var(--bg-input);
  color: var(--text-secondary);
  border: 1px solid var(--border-color);
  font-weight: 600;
  font-size: 0.92rem;
  border-radius: var(--radius-sm);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  transition: all 0.2s;
}
.btn-secondary:hover {
  border-color: var(--accent);
  color: var(--text-primary);
}

/* Sticky Mobile Bottom Bar */
.sticky-mobile-bar {
  display: none;
  position: fixed;
  bottom: 0;
  left: 0;
  right: 0;
  background: var(--bg-secondary);
  border-top: 1px solid var(--border-color);
  padding: 10px 16px;
  box-shadow: 0 -4px 16px rgba(0, 0, 0, 0.4);
  z-index: 900;
  justify-content: space-between;
  align-items: center;
}

@media (max-width: 768px) {
  .sticky-mobile-bar {
    display: flex;
  }
}

.sticky-metric {
  display: flex;
  flex-direction: column;
}
.sticky-label {
  font-size: 0.7rem;
  color: var(--text-muted);
  text-transform: uppercase;
}
.sticky-val {
  font-size: 1.15rem;
  font-weight: 800;
  color: var(--accent);
}

.sticky-btn {
  padding: 8px 16px;
  background: var(--accent);
  color: #000;
  border: none;
  border-radius: var(--radius-sm);
  font-weight: 700;
  font-size: 0.85rem;
  cursor: pointer;
}

/* Ad Slot Container */
.ad-slot-container {
  margin: 32px 0 24px;
  padding: 16px;
  background: var(--bg-card);
  border: 1px dashed var(--border-color);
  border-radius: var(--radius);
  text-align: center;
  min-height: 100px;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
}
.ad-disclaimer {
  font-size: 0.7rem;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.5px;
  margin-bottom: 8px;
}

/* SEO Educational Section */
.seo-section {
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius);
  padding: 36px 32px;
  margin-top: 32px;
}

.seo-section h2 {
  font-size: 1.5rem;
  font-weight: 800;
  color: var(--text-primary);
  margin-bottom: 16px;
}

.seo-section h3 {
  font-size: 1.2rem;
  font-weight: 700;
  color: var(--text-primary);
  margin: 28px 0 12px;
}

.seo-section p {
  color: var(--text-secondary);
  margin-bottom: 16px;
  font-size: 0.95rem;
}

.seo-table-wrapper {
  overflow-x: auto;
  margin: 20px 0;
}

.seo-table {
  width: 100%;
  border-collapse: collapse;
  text-align: left;
  font-size: 0.9rem;
}

.seo-table th, .seo-table td {
  padding: 12px 14px;
  border: 1px solid var(--border-color);
}

.seo-table th {
  background: var(--bg-card);
  color: var(--accent);
  font-weight: 700;
}

.seo-table tr:nth-child(even) {
  background: var(--bg-input);
}

/* Related Apps Cluster */
.related-cluster {
  margin-top: 32px;
  padding: 24px;
  background: var(--bg-card);
  border-radius: var(--radius);
  border: 1px solid var(--border-color);
}

.related-title {
  font-size: 1rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 14px;
  display: flex;
  align-items: center;
  gap: 8px;
}

.related-links-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 12px;
}

.related-app-card {
  padding: 12px 14px;
  background: var(--bg-input);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  text-decoration: none;
  color: var(--text-primary);
  display: flex;
  align-items: center;
  gap: 10px;
  transition: all 0.2s;
}
.related-app-card:hover {
  border-color: var(--accent);
  color: var(--accent);
  transform: translateY(-2px);
}

/* FAQ Accordion */
.faq-accordion {
  margin-top: 20px;
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.faq-item {
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  background: var(--bg-card);
  overflow: hidden;
}

.faq-question {
  width: 100%;
  padding: 16px 20px;
  text-align: left;
  background: transparent;
  border: none;
  font-size: 1rem;
  font-weight: 700;
  color: var(--text-primary);
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
}
.faq-question:hover {
  color: var(--accent);
}

.faq-chevron {
  transition: transform 0.2s;
  font-size: 0.8rem;
}
.faq-item.active .faq-chevron {
  transform: rotate(180deg);
}

.faq-answer {
  padding: 0 20px 16px;
  color: var(--text-secondary);
  font-size: 0.92rem;
  line-height: 1.6;
  display: none;
}
.faq-item.active .faq-answer {
  display: block;
}

/* Footer */
footer {
  border-top: 1px solid var(--border-color);
  padding: 24px 0 60px; /* padding for mobile sticky */
  text-align: center;
  color: var(--text-muted);
  font-size: 0.85rem;
  background: var(--bg-secondary);
}

footer a {
  color: var(--text-secondary);
  text-decoration: none;
  transition: color 0.2s;
}
footer a:hover {
  color: var(--accent);
}

/* Toast */
.toast {
  position: fixed;
  bottom: 80px;
  right: 24px;
  background: var(--accent);
  color: #000;
  padding: 12px 20px;
  border-radius: var(--radius-sm);
  font-weight: 700;
  font-size: 0.95rem;
  box-shadow: 0 10px 25px rgba(0, 0, 0, 0.4);
  transform: translateY(100px);
  opacity: 0;
  transition: all 0.3s cubic-bezier(0.16, 1, 0.3, 1);
  z-index: 1000;
}
.toast.show {
  transform: translateY(0);
  opacity: 1;
}

/* Print */
@media print {
  body {
    background: #fff !important;
    color: #000 !important;
  }
  header, .presets-bar, .action-toolbar, .sticky-mobile-bar, .ad-slot-container, .seo-section, .related-cluster, footer, .toast, .appliance-slider {
    display: none !important;
  }
  .card {
    border: 1px solid #ccc !important;
    box-shadow: none !important;
    background: #fff !important;
  }
  .hero-box, .spec-item {
    border: 1px solid #eee !important;
    background: #fafafa !important;
  }
  .hero-num, .spec-val {
    color: #000 !important;
  }
}