/* ==========================================================================
   Carnot Principle & Carnot Cycle Simulator - CSS Design System
   Physics Virtual Laboratory — Thermodynamics
   ========================================================================== */

:root {
  /* Core Dark Palette */
  --bg-dark: #090d16;
  --bg-card: rgba(15, 23, 42, 0.75);
  --bg-card-hover: rgba(30, 41, 59, 0.85);
  --border-color: rgba(51, 65, 85, 0.6);
  --border-glow: rgba(0, 240, 255, 0.35);

  --primary-cyan: #00f0ff;
  --primary-blue: #3b82f6;
  --accent-purple: #a855f7;
  --status-green: #10b981;
  --status-amber: #f59e0b;
  --status-red: #ef4444;

  /* Heat & Reservoir Specific Colors */
  --hot-color: #ff5544;
  --hot-glow: rgba(255, 85, 68, 0.4);
  --cold-color: #3b82f6;
  --cold-glow: rgba(59, 130, 246, 0.4);
  --work-color: #10b981;
  --work-glow: rgba(16, 185, 129, 0.4);
  --adiabatic-color: #a855f7;

  --text-main: #f8fafc;
  --text-muted: #94a3b8;
  --text-dim: #64748b;

  --font-sans: 'Inter', system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-mono: 'Fira Code', monospace;

  --shadow-sm: 0 4px 6px -1px rgba(0, 0, 0, 0.3);
  --shadow-glow: 0 0 20px rgba(0, 240, 255, 0.15);
  --shadow-hot-glow: 0 0 20px rgba(255, 85, 68, 0.25);
  --shadow-cold-glow: 0 0 20px rgba(59, 130, 246, 0.25);

  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 16px;
}

/* Reset & Global Base */
* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html, body {
  width: 100%;
  min-height: 100vh;
  background-color: var(--bg-dark);
  color: var(--text-main);
  font-family: var(--font-sans);
  font-size: 15px;
  line-height: 1.5;
  overflow-x: hidden;
  background-image:
    radial-gradient(circle at 15% 15%, rgba(255, 85, 68, 0.08) 0%, transparent 45%),
    radial-gradient(circle at 85% 85%, rgba(59, 130, 246, 0.08) 0%, transparent 45%),
    linear-gradient(to right, rgba(255, 255, 255, 0.02) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(255, 255, 255, 0.02) 1px, transparent 1px);
  background-size: 100% 100%, 100% 100%, 32px 32px, 32px 32px;
}

.app-container {
  max-width: 1480px;
  margin: 0 auto;
  padding: 1.5rem;
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
}

/* Header */
.app-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 1rem 1.5rem;
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  backdrop-filter: blur(12px);
  box-shadow: var(--shadow-sm);
  flex-wrap: wrap;
  gap: 1rem;
}

.header-branding .lab-badge {
  font-size: 0.72rem;
  font-weight: 700;
  color: var(--primary-cyan);
  letter-spacing: 1.5px;
  text-transform: uppercase;
  margin-bottom: 0.2rem;
}

.header-branding h1 {
  font-size: 1.8rem;
  font-weight: 800;
  color: var(--text-main);
  letter-spacing: -0.5px;
  line-height: 1.2;
}

.header-branding .subtitle {
  font-size: 0.95rem;
  color: var(--text-muted);
}

.status-summary-pill {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  padding: 0.5rem 1rem;
  background: rgba(15, 23, 42, 0.9);
  border: 1px solid var(--border-color);
  border-radius: 30px;
  font-family: var(--font-mono);
  font-size: 0.85rem;
  font-weight: 600;
}

.status-dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background-color: var(--status-green);
  box-shadow: 0 0 10px var(--status-green);
  transition: background-color 0.3s ease, box-shadow 0.3s ease;
}

.status-dot.running {
  background-color: var(--primary-cyan);
  box-shadow: 0 0 12px var(--primary-cyan);
  animation: pulse-dot 1.5s infinite;
}

.status-dot.complete {
  background-color: var(--status-amber);
  box-shadow: 0 0 10px var(--status-amber);
}

@keyframes pulse-dot {
  0%, 100% { opacity: 1; transform: scale(1); }
  50% { opacity: 0.5; transform: scale(1.2); }
}

/* Card General Style */
.card {
  background: var(--bg-card);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 1.25rem;
  box-shadow: var(--shadow-sm);
  transition: border-color 0.2s ease, box-shadow 0.2s ease;
}

.card:hover {
  border-color: rgba(0, 240, 255, 0.25);
}

.card-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 1rem;
  padding-bottom: 0.75rem;
  border-bottom: 1px solid rgba(255, 255, 255, 0.08);
  flex-wrap: wrap;
  gap: 0.5rem;
}

.card-header h2, .card-header h3 {
  font-size: 1.15rem;
  font-weight: 600;
  color: var(--text-main);
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.card-header h2 svg, .card-header h3 svg {
  color: var(--primary-cyan);
  flex-shrink: 0;
}

/* Badges */
.badge {
  font-size: 0.75rem;
  font-weight: 600;
  padding: 0.25rem 0.65rem;
  border-radius: 20px;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  white-space: nowrap;
}

.badge.cyan {
  background: rgba(0, 240, 255, 0.12);
  color: var(--primary-cyan);
  border: 1px solid rgba(0, 240, 255, 0.3);
}

.badge.hot {
  background: rgba(255, 85, 68, 0.12);
  color: var(--hot-color);
  border: 1px solid rgba(255, 85, 68, 0.3);
}

.badge.cold {
  background: rgba(59, 130, 246, 0.12);
  color: var(--cold-color);
  border: 1px solid rgba(59, 130, 246, 0.3);
}

.badge.purple {
  background: rgba(168, 85, 247, 0.12);
  color: var(--accent-purple);
  border: 1px solid rgba(168, 85, 247, 0.3);
}

.badge.green {
  background: rgba(16, 185, 129, 0.12);
  color: var(--status-green);
  border: 1px solid rgba(16, 185, 129, 0.3);
}

/* Monospace Badges */
.mono-badge {
  font-family: var(--font-mono);
  font-size: 0.85rem;
  padding: 0.2rem 0.5rem;
  background: rgba(15, 23, 42, 0.8);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  color: var(--primary-cyan);
}

/* Toolbar & Parameters */
.toolbar-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 1.25rem;
  align-items: center;
}

.control-group {
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
}

.control-label {
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.8px;
  color: var(--text-muted);
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.range-slider {
  width: 100%;
  accent-color: var(--primary-cyan);
  height: 6px;
  background: rgba(255, 255, 255, 0.1);
  border-radius: 4px;
  outline: none;
  cursor: pointer;
}

.range-slider.hot-slider {
  accent-color: var(--hot-color);
}

.range-slider.cold-slider {
  accent-color: var(--cold-color);
}

.button-toolbar {
  display: flex;
  gap: 0.75rem;
  flex-wrap: wrap;
  align-items: center;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.65rem 1.2rem;
  font-family: var(--font-sans);
  font-size: 0.9rem;
  font-weight: 600;
  border-radius: var(--radius-sm);
  border: 1px solid transparent;
  cursor: pointer;
  transition: all 0.2s ease;
}

.btn-primary {
  background: linear-gradient(135deg, rgba(0, 240, 255, 0.2), rgba(59, 130, 246, 0.3));
  border-color: var(--primary-cyan);
  color: #fff;
  box-shadow: 0 0 15px rgba(0, 240, 255, 0.2);
}

.btn-primary:hover {
  background: linear-gradient(135deg, rgba(0, 240, 255, 0.3), rgba(59, 130, 246, 0.4));
  box-shadow: 0 0 20px rgba(0, 240, 255, 0.4);
}

.btn-secondary {
  background: rgba(30, 41, 59, 0.8);
  border-color: var(--border-color);
  color: var(--text-main);
}

.btn-secondary:hover {
  background: rgba(51, 65, 85, 0.8);
  border-color: rgba(255, 255, 255, 0.2);
}

.btn-danger {
  background: rgba(239, 68, 68, 0.15);
  border-color: rgba(239, 68, 68, 0.4);
  color: #fca5a5;
}

.btn-danger:hover {
  background: rgba(239, 68, 68, 0.3);
  color: #fff;
}

.btn:disabled {
  opacity: 0.4;
  cursor: not-allowed;
  box-shadow: none !important;
}

/* Stage Indicator Banner */
.stage-banner {
  background: linear-gradient(135deg, rgba(15, 23, 42, 0.9), rgba(30, 41, 59, 0.7));
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 1rem 1.25rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  position: relative;
  overflow: hidden;
}

.stage-info {
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
}

.stage-label-sm {
  font-size: 0.72rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 1.2px;
  color: var(--text-muted);
}

.stage-title {
  font-size: 1.25rem;
  font-weight: 800;
  color: var(--primary-cyan);
  letter-spacing: -0.3px;
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.stage-desc {
  font-size: 0.88rem;
  color: var(--text-muted);
}

.stage-progress-bar-container {
  width: 180px;
  height: 8px;
  background: rgba(255, 255, 255, 0.08);
  border-radius: 4px;
  overflow: hidden;
  border: 1px solid var(--border-color);
}

.stage-progress-bar {
  height: 100%;
  width: 0%;
  background: linear-gradient(90deg, var(--primary-cyan), var(--primary-blue));
  transition: width 0.1s linear;
}

/* Cycle Stage Step Indicators */
.stage-steps {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 0.75rem;
}

.stage-step-card {
  background: rgba(15, 23, 42, 0.6);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  padding: 0.75rem;
  text-align: center;
  transition: all 0.3s ease;
  position: relative;
  cursor: pointer;
}

.stage-step-card:hover {
  background: rgba(30, 41, 59, 0.7);
}

.stage-step-card.active {
  background: rgba(0, 240, 255, 0.1);
  border-color: var(--primary-cyan);
  box-shadow: 0 0 15px rgba(0, 240, 255, 0.2);
}

.stage-step-card.active .step-num {
  background: var(--primary-cyan);
  color: var(--bg-dark);
}

.step-num {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 22px;
  height: 22px;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.1);
  color: var(--text-muted);
  font-family: var(--font-mono);
  font-size: 0.75rem;
  font-weight: 700;
  margin-bottom: 0.4rem;
}

.step-title {
  font-size: 0.8rem;
  font-weight: 700;
  color: var(--text-main);
  line-height: 1.2;
}

.step-sub {
  font-size: 0.7rem;
  color: var(--text-muted);
  margin-top: 0.2rem;
}

/* Main Display Grid */
.main-layout-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1.25rem;
}

@media (max-width: 1024px) {
  .main-layout-grid {
    grid-template-columns: 1fr;
  }
}

/* SVG Apparatus Container */
.svg-container {
  width: 100%;
  height: 480px;
  background: rgba(10, 15, 28, 0.9);
  border-radius: var(--radius-sm);
  border: 1px solid rgba(255, 255, 255, 0.05);
  position: relative;
  overflow: hidden;
}

.svg-container svg {
  width: 100%;
  height: 100%;
}

/* Diagrams Grid */
.diagrams-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
}

@media (max-width: 640px) {
  .diagrams-grid {
    grid-template-columns: 1fr;
  }
}

.diagram-card {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.canvas-wrapper {
  position: relative;
  width: 100%;
  height: 260px;
  background: rgba(10, 15, 28, 0.95);
  border-radius: var(--radius-sm);
  border: 1px solid var(--border-color);
  overflow: hidden;
}

.canvas-wrapper canvas {
  width: 100%;
  height: 100%;
  display: block;
}

/* Digital Measurement Metrics */
.metrics-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 1rem;
}

.metric-card {
  background: rgba(15, 23, 42, 0.7);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  padding: 1rem;
  display: flex;
  flex-direction: column;
  gap: 0.3rem;
  position: relative;
}

.metric-card.accent-cyan { border-left: 4px solid var(--primary-cyan); }
.metric-card.accent-hot { border-left: 4px solid var(--hot-color); }
.metric-card.accent-cold { border-left: 4px solid var(--cold-color); }
.metric-card.accent-green { border-left: 4px solid var(--status-green); }
.metric-card.accent-purple { border-left: 4px solid var(--accent-purple); }

.metric-title {
  font-size: 0.72rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.8px;
  color: var(--text-muted);
}

.metric-value {
  font-family: var(--font-mono);
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--text-main);
}

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

/* Observation Table */
.table-responsive {
  width: 100%;
  overflow-x: auto;
}

.obs-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.85rem;
  text-align: left;
}

.obs-table th {
  background: rgba(30, 41, 59, 0.8);
  color: var(--primary-cyan);
  font-weight: 700;
  text-transform: uppercase;
  font-size: 0.72rem;
  letter-spacing: 0.8px;
  padding: 0.75rem 1rem;
  border-bottom: 2px solid var(--border-color);
  white-space: nowrap;
}

.obs-table td {
  padding: 0.75rem 1rem;
  border-bottom: 1px solid rgba(255, 255, 255, 0.06);
  color: var(--text-main);
  font-family: var(--font-mono);
  white-space: nowrap;
}

.obs-table tbody tr {
  transition: background 0.2s ease;
}

.obs-table tbody tr.active-row {
  background: rgba(0, 240, 255, 0.12);
}

.obs-table tbody tr.active-row td {
  color: var(--primary-cyan);
  font-weight: 700;
}

/* Comparison Panel */
.comparison-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1.25rem;
}

@media (max-width: 768px) {
  .comparison-grid {
    grid-template-columns: 1fr;
  }
}

.comp-card {
  background: rgba(15, 23, 42, 0.6);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  padding: 1rem;
}

.comp-card.carnot {
  border-top: 3px solid var(--primary-cyan);
}

.comp-card.real {
  border-top: 3px solid var(--status-amber);
}

.comp-title {
  font-size: 1rem;
  font-weight: 700;
  margin-bottom: 0.75rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.comp-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  font-size: 0.85rem;
  color: var(--text-muted);
}

.comp-list li {
  position: relative;
  padding-left: 1.2rem;
  line-height: 1.4;
}

.comp-list li::before {
  content: "•";
  position: absolute;
  left: 0.3rem;
  color: var(--primary-cyan);
  font-weight: bold;
}

.comp-card.real .comp-list li::before {
  color: var(--status-amber);
}

/* Educational Section Tabs / Accordion */
.edu-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 1.25rem;
}

.edu-box {
  background: rgba(15, 23, 42, 0.6);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  padding: 1rem;
}

.edu-box h4 {
  font-size: 0.95rem;
  font-weight: 700;
  color: var(--primary-cyan);
  margin-bottom: 0.5rem;
  display: flex;
  align-items: center;
  gap: 0.4rem;
}

.edu-box p {
  font-size: 0.85rem;
  color: var(--text-muted);
  line-height: 1.5;
  margin-bottom: 0.5rem;
}

.edu-box ul {
  padding-left: 1.2rem;
  font-size: 0.82rem;
  color: var(--text-muted);
}

.edu-box ul li {
  margin-bottom: 0.3rem;
}

.formula-box {
  background: rgba(0, 0, 0, 0.4);
  border: 1px solid rgba(0, 240, 255, 0.2);
  border-radius: var(--radius-sm);
  padding: 0.6rem;
  margin: 0.5rem 0;
  font-family: var(--font-mono);
  font-size: 0.9rem;
  color: var(--primary-cyan);
  text-align: center;
}

/* Footer */
.app-footer {
  text-align: center;
  padding: 1rem;
  font-size: 0.8rem;
  color: var(--text-dim);
  border-top: 1px solid rgba(255, 255, 255, 0.05);
}

/* ==========================================================================
   LIGHT THEME DESIGN SYSTEM OVERRIDES
   ========================================================================== */

html[data-theme="light"],
html:not(.dark):not([data-theme="dark"]) {
  --bg-dark: #f8fafc;
  --bg-card: #ffffff;
  --bg-card-hover: #f1f5f9;
  --border-color: #e2e8f0;
  --border-glow: rgba(2, 132, 199, 0.25);

  --primary-cyan: #0284c7;
  --primary-blue: #2563eb;
  --accent-purple: #9333ea;
  --status-green: #059669;
  --status-amber: #d97706;
  --status-red: #dc2626;

  --hot-color: #ea580c;
  --hot-glow: rgba(234, 88, 12, 0.2);
  --cold-color: #0284c7;
  --cold-glow: rgba(2, 132, 199, 0.2);
  --work-color: #059669;
  --work-glow: rgba(5, 150, 105, 0.2);
  --adiabatic-color: #9333ea;

  --text-main: #0f172a;
  --text-muted: #475569;
  --text-dim: #64748b;

  --shadow-sm: 0 4px 20px -2px rgba(0, 0, 0, 0.05);
  --shadow-glow: 0 0 20px rgba(2, 132, 199, 0.15);
  --shadow-hot-glow: 0 0 20px rgba(234, 88, 12, 0.15);
  --shadow-cold-glow: 0 0 20px rgba(2, 132, 199, 0.15);
}

html[data-theme="light"] body,
html:not(.dark):not([data-theme="dark"]) body {
  background-color: #f8fafc;
  color: #0f172a;
  background-image:
    radial-gradient(circle at 15% 15%, rgba(234, 88, 12, 0.04) 0%, transparent 45%),
    radial-gradient(circle at 85% 85%, rgba(2, 132, 199, 0.04) 0%, transparent 45%),
    linear-gradient(to right, rgba(0, 0, 0, 0.03) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(0, 0, 0, 0.03) 1px, transparent 1px);
}

/* Header */
html[data-theme="light"] .app-header,
html:not(.dark):not([data-theme="dark"]) .app-header {
  background: #ffffff;
  border-color: #e2e8f0;
  box-shadow: 0 4px 20px -2px rgba(0, 0, 0, 0.05);
}

html[data-theme="light"] .header-branding h1,
html:not(.dark):not([data-theme="dark"]) .header-branding h1 {
  background: linear-gradient(90deg, #0f172a, #0284c7);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

html[data-theme="light"] .header-branding .lab-badge,
html:not(.dark):not([data-theme="dark"]) .header-branding .lab-badge {
  color: #0284c7;
}

html[data-theme="light"] .header-branding .subtitle,
html:not(.dark):not([data-theme="dark"]) .header-branding .subtitle {
  color: #64748b;
}

/* Status Pill */
html[data-theme="light"] .status-summary-pill,
html:not(.dark):not([data-theme="dark"]) .status-summary-pill {
  background: #f1f5f9;
  border-color: #cbd5e1;
  color: #0f172a;
}

/* Cards & Layout */
html[data-theme="light"] .card,
html:not(.dark):not([data-theme="dark"]) .card {
  background: #ffffff;
  border-color: #e2e8f0;
  box-shadow: 0 4px 20px -2px rgba(0, 0, 0, 0.05);
}

html[data-theme="light"] .card:hover,
html:not(.dark):not([data-theme="dark"]) .card:hover {
  border-color: #bae6fd;
}

html[data-theme="light"] .card-header,
html:not(.dark):not([data-theme="dark"]) .card-header {
  border-bottom-color: #f1f5f9;
}

html[data-theme="light"] .card-header h2,
html[data-theme="light"] .card-header h3,
html:not(.dark):not([data-theme="dark"]) .card-header h2,
html:not(.dark):not([data-theme="dark"]) .card-header h3 {
  color: #0f172a;
}

html[data-theme="light"] .card-header h2 svg,
html[data-theme="light"] .card-header h3 svg,
html:not(.dark):not([data-theme="dark"]) .card-header h2 svg,
html:not(.dark):not([data-theme="dark"]) .card-header h3 svg {
  color: #0284c7;
}

/* Badges */
html[data-theme="light"] .badge.cyan,
html:not(.dark):not([data-theme="dark"]) .badge.cyan {
  background: #f0f9ff;
  color: #0284c7;
  border-color: #bae6fd;
}

html[data-theme="light"] .badge.hot,
html:not(.dark):not([data-theme="dark"]) .badge.hot {
  background: #fff7ed;
  color: #ea580c;
  border-color: #fed7aa;
}

html[data-theme="light"] .badge.cold,
html:not(.dark):not([data-theme="dark"]) .badge.cold {
  background: #eff6ff;
  color: #2563eb;
  border-color: #bfdbfe;
}

html[data-theme="light"] .badge.purple,
html:not(.dark):not([data-theme="dark"]) .badge.purple {
  background: #faf5ff;
  color: #9333ea;
  border-color: #e9d5ff;
}

html[data-theme="light"] .badge.green,
html:not(.dark):not([data-theme="dark"]) .badge.green {
  background: #ecfdf5;
  color: #059669;
  border-color: #a7f3d0;
}

html[data-theme="light"] .mono-badge,
html:not(.dark):not([data-theme="dark"]) .mono-badge {
  background: #f1f5f9;
  border-color: #cbd5e1;
  color: #0284c7;
}

/* Sliders & Controls */
html[data-theme="light"] .control-label,
html:not(.dark):not([data-theme="dark"]) .control-label {
  color: #475569;
}

html[data-theme="light"] .range-slider,
html:not(.dark):not([data-theme="dark"]) .range-slider {
  background: #e2e8f0;
  accent-color: #0284c7;
}

html[data-theme="light"] .range-slider.hot-slider,
html:not(.dark):not([data-theme="dark"]) .range-slider.hot-slider {
  accent-color: #ea580c;
}

html[data-theme="light"] .range-slider.cold-slider,
html:not(.dark):not([data-theme="dark"]) .range-slider.cold-slider {
  accent-color: #0284c7;
}

/* Buttons */
html[data-theme="light"] .btn-primary,
html:not(.dark):not([data-theme="dark"]) .btn-primary {
  background: linear-gradient(135deg, #0284c7, #2563eb);
  border-color: #0284c7;
  color: #ffffff;
  box-shadow: 0 4px 14px rgba(2, 132, 199, 0.3);
}

html[data-theme="light"] .btn-primary:hover,
html:not(.dark):not([data-theme="dark"]) .btn-primary:hover {
  background: linear-gradient(135deg, #0369a1, #1d4ed8);
  box-shadow: 0 4px 18px rgba(2, 132, 199, 0.45);
}

html[data-theme="light"] .btn-secondary,
html:not(.dark):not([data-theme="dark"]) .btn-secondary {
  background: #f1f5f9;
  border-color: #cbd5e1;
  color: #334155;
}

html[data-theme="light"] .btn-secondary:hover,
html:not(.dark):not([data-theme="dark"]) .btn-secondary:hover {
  background: #e2e8f0;
  border-color: #94a3b8;
}

html[data-theme="light"] .btn-danger,
html:not(.dark):not([data-theme="dark"]) .btn-danger {
  background: #fef2f2;
  border-color: #fecaca;
  color: #dc2626;
}

html[data-theme="light"] .btn-danger:hover,
html:not(.dark):not([data-theme="dark"]) .btn-danger:hover {
  background: #fee2e2;
  color: #b91c1c;
}

/* Stage Banner */
html[data-theme="light"] .stage-banner,
html:not(.dark):not([data-theme="dark"]) .stage-banner {
  background: #f0f9ff;
  border-color: #bae6fd;
  box-shadow: 0 2px 10px rgba(2, 132, 199, 0.08);
}

html[data-theme="light"] .stage-label-sm,
html:not(.dark):not([data-theme="dark"]) .stage-label-sm {
  color: #0369a1;
}

html[data-theme="light"] .stage-title,
html:not(.dark):not([data-theme="dark"]) .stage-title {
  color: #0284c7;
}

html[data-theme="light"] .stage-desc,
html:not(.dark):not([data-theme="dark"]) .stage-desc {
  color: #475569;
}

html[data-theme="light"] .stage-progress-bar-container,
html:not(.dark):not([data-theme="dark"]) .stage-progress-bar-container {
  background: #e0f2fe;
  border-color: #bae6fd;
}

/* 4-Step Cards */
html[data-theme="light"] .stage-step-card,
html:not(.dark):not([data-theme="dark"]) .stage-step-card {
  background: #f8fafc;
  border-color: #e2e8f0;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.04);
}

html[data-theme="light"] .stage-step-card:hover,
html:not(.dark):not([data-theme="dark"]) .stage-step-card:hover {
  background: #f1f5f9;
  border-color: #cbd5e1;
}

html[data-theme="light"] .stage-step-card.active,
html:not(.dark):not([data-theme="dark"]) .stage-step-card.active {
  background: #f0f9ff;
  border-color: #0284c7;
  box-shadow: 0 0 15px rgba(2, 132, 199, 0.15);
}

html[data-theme="light"] .step-num,
html:not(.dark):not([data-theme="dark"]) .step-num {
  background: #e2e8f0;
  color: #475569;
}

html[data-theme="light"] .stage-step-card.active .step-num,
html:not(.dark):not([data-theme="dark"]) .stage-step-card.active .step-num {
  background: #0284c7;
  color: #ffffff;
}

html[data-theme="light"] .step-title,
html:not(.dark):not([data-theme="dark"]) .step-title {
  color: #0f172a;
}

html[data-theme="light"] .step-sub,
html:not(.dark):not([data-theme="dark"]) .step-sub {
  color: #64748b;
}

/* Apparatus SVG Container */
html[data-theme="light"] .svg-container,
html:not(.dark):not([data-theme="dark"]) .svg-container {
  background: #f8fafc;
  border-color: #e2e8f0;
}

html[data-theme="light"] #svgGrid path,
html:not(.dark):not([data-theme="dark"]) #svgGrid path {
  stroke: rgba(0, 0, 0, 0.04);
}

html[data-theme="light"] #workOutputGroup circle:first-child,
html:not(.dark):not([data-theme="dark"]) #workOutputGroup circle:first-child {
  fill: #f1f5f9;
  stroke: #059669;
}

html[data-theme="light"] #workOutputGroup rect,
html:not(.dark):not([data-theme="dark"]) #workOutputGroup rect {
  fill: #ecfdf5;
  stroke: #10b981;
}

html[data-theme="light"] #svgTextW,
html:not(.dark):not([data-theme="dark"]) #svgTextW {
  fill: #065f46;
}

html[data-theme="light"] #svgGasTemp,
html:not(.dark):not([data-theme="dark"]) #svgGasTemp {
  fill: #0f172a;
}

html[data-theme="light"] #svgGasPV,
html:not(.dark):not([data-theme="dark"]) #svgGasPV {
  fill: #0284c7;
}

/* Diagrams Canvas Wrapper */
html[data-theme="light"] .canvas-wrapper,
html:not(.dark):not([data-theme="dark"]) .canvas-wrapper {
  background: #ffffff;
  border-color: #e2e8f0;
}

/* Metric Cards */
html[data-theme="light"] .metric-card,
html:not(.dark):not([data-theme="dark"]) .metric-card {
  background: #f8fafc;
  border-color: #e2e8f0;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.03);
}

html[data-theme="light"] .metric-title,
html:not(.dark):not([data-theme="dark"]) .metric-title {
  color: #64748b;
}

html[data-theme="light"] .metric-value,
html:not(.dark):not([data-theme="dark"]) .metric-value {
  color: #0f172a;
}

html[data-theme="light"] .metric-sub,
html:not(.dark):not([data-theme="dark"]) .metric-sub {
  color: #64748b;
}

/* Observation Table */
html[data-theme="light"] .obs-table th,
html:not(.dark):not([data-theme="dark"]) .obs-table th {
  background: #f1f5f9;
  color: #0369a1;
  border-bottom-color: #cbd5e1;
}

html[data-theme="light"] .obs-table td,
html:not(.dark):not([data-theme="dark"]) .obs-table td {
  border-bottom-color: #e2e8f0;
  color: #334155;
}

html[data-theme="light"] .obs-table tbody tr:hover,
html:not(.dark):not([data-theme="dark"]) .obs-table tbody tr:hover {
  background: #f8fafc;
}

html[data-theme="light"] .obs-table tbody tr.active-row,
html:not(.dark):not([data-theme="dark"]) .obs-table tbody tr.active-row {
  background: #f0f9ff;
}

html[data-theme="light"] .obs-table tbody tr.active-row td,
html:not(.dark):not([data-theme="dark"]) .obs-table tbody tr.active-row td {
  color: #0284c7;
}

/* Comparison Panel */
html[data-theme="light"] .comp-card,
html:not(.dark):not([data-theme="dark"]) .comp-card {
  background: #f8fafc;
  border-color: #e2e8f0;
}

html[data-theme="light"] .comp-title,
html:not(.dark):not([data-theme="dark"]) .comp-title {
  color: #0f172a;
}

html[data-theme="light"] .comp-list,
html:not(.dark):not([data-theme="dark"]) .comp-list {
  color: #475569;
}

/* Educational Section */
html[data-theme="light"] .edu-box,
html:not(.dark):not([data-theme="dark"]) .edu-box {
  background: #f8fafc;
  border-color: #e2e8f0;
}

html[data-theme="light"] .edu-box h4,
html:not(.dark):not([data-theme="dark"]) .edu-box h4 {
  color: #0284c7;
}

html[data-theme="light"] .edu-box p,
html[data-theme="light"] .edu-box ul,
html:not(.dark):not([data-theme="dark"]) .edu-box p,
html:not(.dark):not([data-theme="dark"]) .edu-box ul {
  color: #475569;
}

html[data-theme="light"] .formula-box,
html:not(.dark):not([data-theme="dark"]) .formula-box {
  background: #f0f9ff;
  border-color: #bae6fd;
  color: #0369a1;
}

/* Footer */
html[data-theme="light"] .app-footer,
html:not(.dark):not([data-theme="dark"]) .app-footer {
  border-top-color: #e2e8f0;
  color: #64748b;
}