/* ═══════════════════════════════════════════════════════════════════════════
   PHYSICSFORUM.ORG — PHYSICSLAB STYLES
   Mobile-first, simulation browser + simulation pages
   ═══════════════════════════════════════════════════════════════════════════ */

/* ── Lab Index Page (lighter gradient, no black) ── */
.lab-hero {
  position: relative;
  overflow: hidden;
  background:
    radial-gradient(900px 500px at 20% 30%, rgba(124,58,237,0.25), transparent 60%),
    radial-gradient(800px 400px at 80% 70%, rgba(245,158,11,0.18), transparent 60%),
    linear-gradient(135deg, #1B3A6B 0%, #2563EB 50%, #4F46E5 100%);
  min-height: 50vh;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: var(--space-16) var(--space-6);
}

.lab-hero-canvas {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  z-index: 1;
}

.lab-hero-content {
  position: relative;
  z-index: 2;
  max-width: 800px;
}

.lab-hero-badge {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-1) var(--space-4);
  background: rgba(37, 99, 235, 0.15);
  border: 1px solid rgba(37, 99, 235, 0.3);
  border-radius: var(--radius-full);
  color: var(--color-electric);
  font-size: var(--text-sm);
  font-weight: 600;
  font-family: var(--font-display);
  margin-bottom: var(--space-6);
}

.lab-hero-badge svg {
  width: 16px;
  height: 16px;
  animation: atomSpin 3s linear infinite;
}

@keyframes atomSpin {
  from { transform: rotate(0deg); }
  to   { transform: rotate(360deg); }
}

.lab-hero-content h1 {
  font-family: var(--font-display);
  font-weight: 800;
  font-size: var(--text-3xl);
  color: var(--color-photon-white);
  line-height: 1.15;
  letter-spacing: -0.02em;
  margin-bottom: var(--space-4);
}

.lab-hero-content h1 span.gradient-text {
  background: linear-gradient(135deg, var(--color-electric), var(--color-quantum-gold));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.lab-hero-content p {
  font-family: var(--font-body);
  font-size: var(--text-lg);
  color: var(--color-neutron-grey);
  max-width: 580px;
  margin: 0 auto var(--space-8);
  line-height: 1.7;
}

.lab-hero-stats {
  display: flex;
  gap: var(--space-8);
  justify-content: center;
  flex-wrap: wrap;
}

.lab-hero-stat {
  text-align: center;
}

.lab-hero-stat-value {
  font-family: var(--font-display);
  font-size: var(--text-2xl);
  font-weight: 700;
  color: var(--color-quantum-gold);
}

.lab-hero-stat-label {
  font-size: var(--text-xs);
  color: var(--color-neutron-grey);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  margin-top: var(--space-1);
}

/* Filter Bar */
.lab-filter-bar {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-4) var(--space-6);
  background: var(--color-photon-white);
  border-bottom: 1px solid rgba(148, 163, 184, 0.15);
  position: sticky;
  top: 0;
  z-index: var(--z-sticky);
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
  scrollbar-width: none;
}

.lab-filter-bar::-webkit-scrollbar { display: none; }

.lab-filter-label {
  font-family: var(--font-display);
  font-size: var(--text-sm);
  font-weight: 600;
  color: var(--color-dark-grey);
  white-space: nowrap;
  margin-right: var(--space-2);
  flex-shrink: 0;
}

.lab-filter-btn {
  flex-shrink: 0;
  padding: var(--space-2) var(--space-4);
  border: 1.5px solid rgba(148, 163, 184, 0.25);
  border-radius: var(--radius-full);
  background: transparent;
  color: var(--color-dark-grey);
  font-family: var(--font-display);
  font-size: var(--text-sm);
  font-weight: 500;
  cursor: pointer;
  transition: var(--transition-fast);
  white-space: nowrap;
}

.lab-filter-btn:hover {
  border-color: var(--color-electric);
  color: var(--color-electric);
}

.lab-filter-btn.active {
  background: var(--color-electric);
  border-color: var(--color-electric);
  color: var(--text-inverse);
}

/* Simulation Cards Grid */
.lab-grid {
  padding: var(--space-8) var(--space-6);
  max-width: 1280px;
  margin: 0 auto;
}

.lab-grid-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: var(--space-6);
  flex-wrap: wrap;
  gap: var(--space-3);
}

.lab-grid-header h2 {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: var(--text-2xl);
  color: var(--color-dark-grey);
}

.lab-grid-count {
  font-size: var(--text-sm);
  color: var(--color-neutron-grey);
  font-weight: 400;
}

.lab-cards {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-6);
}

/* Simulation Card */
.lab-card {
  background: var(--color-photon-white);
  border-radius: var(--radius-xl);
  border: 1px solid rgba(148, 163, 184, 0.15);
  overflow: hidden;
  transition: var(--transition-base);
  position: relative;
}

.lab-card:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-lg);
  border-color: rgba(37, 99, 235, 0.25);
}

.lab-card-preview {
  position: relative;
  height: 180px;
  background: var(--color-code-bg);
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
}

.lab-card-preview canvas,
.lab-card-preview svg {
  width: 100%;
  height: 100%;
}

.lab-card-preview .preview-fallback {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-3);
  color: var(--color-neutron-grey);
}

.lab-card-preview .preview-icon {
  width: 56px;
  height: 56px;
  opacity: 0.4;
}

.lab-card-pro-badge {
  position: absolute;
  top: var(--space-3);
  right: var(--space-3);
  display: flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-1) var(--space-3);
  background: rgba(124, 58, 237, 0.9);
  color: var(--text-inverse);
  font-size: var(--text-xs);
  font-weight: 700;
  font-family: var(--font-display);
  border-radius: var(--radius-full);
  backdrop-filter: blur(4px);
}

.lab-card-body {
  padding: var(--space-5);
}

.lab-card-badges {
  display: flex;
  gap: var(--space-2);
  flex-wrap: wrap;
  margin-bottom: var(--space-3);
}

.lab-card-badges .badge {
  font-size: 0.7rem;
}

.lab-card-title {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: var(--text-lg);
  color: var(--color-dark-grey);
  margin-bottom: var(--space-2);
  line-height: 1.3;
}

.lab-card-desc {
  font-family: var(--font-body);
  font-size: var(--text-sm);
  color: var(--color-neutron-grey);
  line-height: 1.6;
  margin-bottom: var(--space-4);
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.lab-card-tags {
  display: flex;
  gap: var(--space-2);
  flex-wrap: wrap;
  margin-bottom: var(--space-4);
}

.lab-card-tags .tag {
  font-size: 0.7rem;
  padding: 2px 10px;
}

.lab-card-footer {
  padding: var(--space-4) var(--space-5);
  background: rgba(148, 163, 184, 0.03);
  border-top: 1px solid rgba(148, 163, 184, 0.1);
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.lab-card-footer .btn {
  font-size: var(--text-xs);
}

/* ── Simulation Page Template ── */
.sim-page {
  display: flex;
  min-height: calc(100vh - 64px);
}

.sim-canvas-section {
  flex: 1;
  display: flex;
  flex-direction: column;
  background: linear-gradient(180deg, var(--surface-page) 0%, #E0E7FF 100%);
  min-height: calc(100vh - 68px);
}

.sim-canvas-header {
  display: flex;
  align-items: center;
  gap: var(--space-4);
  padding: var(--space-3) var(--space-5);
  background: var(--surface);
  border-bottom: 1px solid rgba(148,163,184,0.18);
  box-shadow: 0 1px 4px rgba(15,23,42,0.04);
}

.sim-canvas-header .sim-title {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: var(--text-base);
  color: var(--color-space-navy);
}

.sim-canvas-header .sim-actions {
  display: flex;
  gap: var(--space-2);
  margin-left: auto;
}

.sim-canvas-header .btn {
  padding: var(--space-1) var(--space-3);
  font-size: var(--text-xs);
}

.sim-canvas-container {
  flex: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 24px;
  position: relative;
  min-height: 480px;
  background: var(--surface);
  margin: 16px;
  border-radius: 12px;
  border: 1px solid rgba(148,163,184,0.18);
  box-shadow: 0 2px 10px rgba(15,23,42,0.04);
}

.sim-canvas-container canvas {
  border-radius: var(--radius-md);
  max-width: 100%;
  max-height: 100%;
  display: block;
}

#fps-display {
  position: absolute;
  top: 24px;
  right: 24px;
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  color: var(--text-body);
  background: rgba(255,255,255,0.9);
  border: 1px solid rgba(148,163,184,0.2);
  padding: 3px 10px;
  border-radius: var(--radius-full);
  pointer-events: none;
}

.sim-placeholder {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-6);
  color: var(--color-neutron-grey);
}

.sim-placeholder svg {
  width: 100px;
  height: 100px;
  opacity: 0.3;
}

.sim-placeholder h3 {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: var(--text-2xl);
  color: var(--color-photon-white);
}

.sim-placeholder p {
  font-size: var(--text-base);
  max-width: 400px;
  text-align: center;
  line-height: 1.7;
}

/* ── Sidebar Controls ── */
.sim-sidebar {
  width: 320px;
  max-width: 100%;
  background: var(--color-photon-white);
  border-left: 1px solid rgba(148, 163, 184, 0.15);
  display: flex;
  flex-direction: column;
  overflow-y: auto;
  flex-shrink: 0;
}

.sim-sidebar-section {
  padding: var(--space-5);
  border-bottom: 1px solid rgba(148, 163, 184, 0.1);
}

.sim-sidebar-section:last-child {
  border-bottom: none;
}

.sim-sidebar-section h4 {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: var(--text-sm);
  color: var(--color-dark-grey);
  text-transform: uppercase;
  letter-spacing: 0.06em;
  margin-bottom: var(--space-4);
}

.sim-control-group {
  margin-bottom: var(--space-4);
}

.sim-control-group:last-child {
  margin-bottom: 0;
}

.sim-control-label {
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-family: var(--font-display);
  font-size: var(--text-xs);
  font-weight: 500;
  color: var(--color-dark-grey);
  margin-bottom: var(--space-1);
}

.sim-control-value {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  color: var(--color-electric);
  font-weight: 600;
}

.sim-slider {
  -webkit-appearance: none;
  appearance: none;
  width: 100%;
  height: 6px;
  background: rgba(148, 163, 184, 0.2);
  border-radius: var(--radius-full);
  outline: none;
}

.sim-slider::-webkit-slider-thumb {
  -webkit-appearance: none;
  appearance: none;
  width: 18px;
  height: 18px;
  border-radius: 50%;
  background: var(--color-electric);
  cursor: pointer;
  border: 2px solid #fff;
  box-shadow: var(--shadow-sm);
  transition: var(--transition-fast);
}

.sim-slider::-webkit-slider-thumb:hover {
  transform: scale(1.15);
  box-shadow: var(--shadow-glow);
}

.sim-slider::-moz-range-thumb {
  width: 18px;
  height: 18px;
  border-radius: 50%;
  background: var(--color-electric);
  cursor: pointer;
  border: 2px solid #fff;
  box-shadow: var(--shadow-sm);
}

.sim-color-picker {
  display: flex;
  align-items: center;
  gap: var(--space-3);
}

.sim-color-picker input[type="color"] {
  -webkit-appearance: none;
  appearance: none;
  width: 36px;
  height: 36px;
  border: 2px solid rgba(148, 163, 184, 0.3);
  border-radius: var(--radius-md);
  cursor: pointer;
  padding: 2px;
}

.sim-color-picker input[type="color"]::-webkit-color-swatch-wrapper {
  padding: 0;
}

.sim-color-picker input[type="color"]::-webkit-color-swatch {
  border: none;
  border-radius: 3px;
}

.sim-color-picker span {
  font-size: var(--text-xs);
  color: var(--color-neutron-grey);
}

.sim-toggle-row {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  margin-bottom: var(--space-3);
}

.sim-toggle-row:last-child { margin-bottom: 0; }

.sim-toggle-row label {
  font-family: var(--font-display);
  font-size: var(--text-sm);
  font-weight: 500;
  color: var(--color-dark-grey);
  cursor: pointer;
}

.sim-btn-row {
  display: flex;
  gap: var(--space-2);
  flex-wrap: wrap;
}

.sim-btn-row .btn {
  flex: 1;
  min-width: 0;
  font-size: var(--text-xs);
  padding: var(--space-2) var(--space-3);
}

/* ── Info Panel ── */
.sim-info-panel {
  padding: var(--space-5);
  border-top: 1px solid rgba(148, 163, 184, 0.1);
}

.sim-info-grid {
  display: grid;
  grid-template-columns: 1fr 1fr 1fr;
  gap: var(--space-3);
  margin-bottom: var(--space-5);
}

.sim-info-item {
  text-align: center;
}

.sim-info-value {
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  font-weight: 700;
  color: var(--color-electric);
}

.sim-info-label {
  font-size: var(--text-xs);
  color: var(--color-neutron-grey);
  margin-top: var(--space-1);
}

/* Phase space plot */
.sim-phase-plot {
  margin-top: var(--space-4);
}

.sim-phase-plot h5 {
  font-family: var(--font-display);
  font-weight: 600;
  font-size: var(--text-xs);
  color: var(--color-dark-grey);
  text-transform: uppercase;
  letter-spacing: 0.06em;
  margin-bottom: var(--space-3);
}

.sim-phase-plot canvas {
  width: 100%;
  border-radius: var(--radius-md);
  border: 1px solid rgba(148, 163, 184, 0.15);
}

/* ── Explain the Physics ── */
.explain-section {
  margin-top: var(--space-6);
}

.explain-section details {
  border: 1px solid rgba(148, 163, 184, 0.15);
  border-radius: var(--radius-lg);
  overflow: hidden;
}

.explain-section summary {
  padding: var(--space-4) var(--space-5);
  font-family: var(--font-display);
  font-weight: 600;
  font-size: var(--text-sm);
  color: var(--color-dark-grey);
  cursor: pointer;
  background: rgba(148, 163, 184, 0.04);
  list-style: none;
  display: flex;
  align-items: center;
  gap: var(--space-3);
}

.explain-section summary::-webkit-details-marker { display: none; }

.explain-section summary::before {
  content: '▸';
  display: inline-block;
  transition: transform 0.2s;
  font-size: var(--text-xs);
  color: var(--color-electric);
}

.explain-section details[open] summary::before {
  transform: rotate(90deg);
}

.explain-section .explain-body {
  padding: var(--space-5);
  font-family: var(--font-body);
  font-size: var(--text-base);
  color: var(--color-dark-grey);
  line-height: 1.75;
}

.explain-section .explain-body p {
  margin-bottom: var(--space-4);
}

.explain-section .explain-body p:last-child {
  margin-bottom: 0;
}

.explain-section .equation-block {
  background: var(--color-ice-blue);
  margin: var(--space-4) 0;
}

/* ── Quantum Box Specific ── */
.quantum-info-row {
  display: flex;
  align-items: center;
  gap: var(--space-6);
  padding: var(--space-4) var(--space-5);
  background: rgba(148, 163, 184, 0.04);
  border-radius: var(--radius-lg);
  margin-bottom: var(--space-5);
  flex-wrap: wrap;
}

.quantum-info-stat {
  display: flex;
  flex-direction: column;
  gap: var(--space-1);
}

.quantum-info-stat .stat-label {
  font-size: var(--text-xs);
  color: var(--color-neutron-grey);
  text-transform: uppercase;
  letter-spacing: 0.06em;
  font-weight: 600;
}

.quantum-info-stat .stat-value {
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  font-weight: 700;
  color: var(--color-dark-grey);
}

.quantum-info-stat .stat-value.energy {
  color: var(--color-electric);
  font-size: var(--text-base);
}

.quantum-explanation-text {
  font-family: var(--font-body);
  font-size: var(--text-sm);
  color: var(--color-dark-grey);
  line-height: 1.75;
  padding: var(--space-4) var(--space-5);
  background: var(--color-ice-blue);
  border-radius: var(--radius-lg);
  border-left: 4px solid var(--color-electric);
}

/* ── Responsive ── */
/* Tablet */
@media (min-width: 640px) {
  .lab-hero-content h1 {
    font-size: var(--text-4xl);
  }

  .lab-cards {
    grid-template-columns: repeat(2, 1fr);
  }
}

/* Desktop */
@media (min-width: 1024px) {
  .lab-hero {
    min-height: 70vh;
  }

  .lab-hero-content h1 {
    font-size: var(--text-5xl);
  }

  .lab-cards {
    grid-template-columns: repeat(3, 1fr);
  }

  .sim-page {
    flex-direction: row;
  }

  .sim-sidebar {
    width: 340px;
  }
}

/* Wide */
@media (min-width: 1280px) {
  .sim-sidebar {
    width: 360px;
  }
}

/* ── Mobile: simulation page stacks ── */
@media (max-width: 1023px) {
  .sim-page {
    flex-direction: column;
  }

  .sim-sidebar {
    width: 100%;
    border-left: none;
    border-top: 1px solid rgba(148, 163, 184, 0.15);
    max-height: 50vh;
  }

  .sim-canvas-section {
    min-height: 50vh;
  }

  .sim-info-grid {
    grid-template-columns: 1fr 1fr 1fr;
  }
}

@media (max-width: 639px) {
  .lab-hero {
    min-height: 50vh;
    padding: var(--space-10) var(--space-4);
  }

  .lab-hero-content h1 {
    font-size: var(--text-2xl);
  }

  .lab-hero-stats {
    gap: var(--space-4);
  }

  .lab-hero-stat-value {
    font-size: var(--text-xl);
  }

  .lab-cards {
    grid-template-columns: 1fr;
  }

  .lab-grid {
    padding: var(--space-6) var(--space-4);
  }

  .lab-filter-bar {
    padding: var(--space-3) var(--space-4);
  }

  .sim-info-grid {
    grid-template-columns: 1fr 1fr;
  }
}

/* ── Dark Mode ── */
[data-theme="dark"] .lab-filter-bar {
  background: var(--color-photon-white);
  border-color: rgba(148, 163, 184, 0.08);
}

[data-theme="dark"] .lab-card {
  background: var(--color-slate);
}

[data-theme="dark"] .lab-card:hover {
  border-color: rgba(37, 99, 235, 0.3);
}

[data-theme="dark"] .sim-sidebar {
  background: var(--color-slate);
}

[data-theme="dark"] .sim-sidebar-section {
  border-color: rgba(148, 163, 184, 0.06);
}

[data-theme="dark"] .sim-control-label {
  color: var(--color-dark-grey);
}

[data-theme="dark"] .lab-card-title {
  color: var(--color-dark-grey);
}

[data-theme="dark"] .lab-hero {
  background: #060F1E;
}

[data-theme="dark"] .quantum-info-row {
  background: rgba(255, 255, 255, 0.03);
}

[data-theme="dark"] .quantum-explanation-text {
  background: rgba(37, 99, 235, 0.08);
}