/* ==========================================================================
   PHOTOBIOLOGICAL DOSIMETRY CALCULATOR - DESIGN SYSTEM & THEME TOKENS
   ========================================================================== */

:root, html[data-theme="light"] {
  /* Theme Palette - Light Mode (Default) */
  --bg-dark: #F8FAFC;
  --bg-card: #FFFFFF;
  --bg-card-subtle: #F1F5F9;
  --bg-card-hover: #E2E8F0;
  --bg-input: #F1F5F9;
  --bg-canvas: #FFFFFF;
  
  --border-color: rgba(0, 0, 0, 0.08);
  --border-highlight: rgba(0, 136, 163, 0.35);
  --border-amber: rgba(217, 119, 6, 0.3);

  --text-primary: #0F172A;
  --text-secondary: #334155;
  --text-muted: #64748B;

  --title-gradient: linear-gradient(135deg, #0F172A 0%, #334155 100%);

  /* Accent Colors */
  --accent-cyan: #0088A3;
  --accent-cyan-glow: rgba(0, 136, 163, 0.1);
  --accent-amber: #D97706;
  --accent-amber-glow: rgba(217, 119, 6, 0.1);
  --accent-red: #DC2626;

  /* Typography */
  --font-sans: 'Inter', system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', 'Roboto Mono', monospace;

  /* Spacing & Radii */
  --radius-sm: 8px;
  --radius-md: 14px;
  --radius-lg: 20px;

  --shadow-glow: 0 0 25px rgba(0, 136, 163, 0.07);
  --shadow-card: 0 4px 20px rgba(0, 0, 0, 0.05);
  --glass-backdrop: blur(16px) saturate(180%);
}

/* Dark Mode Overrides */
html[data-theme="dark"] {
  --bg-dark: #090D16;
  --bg-card: rgba(18, 26, 43, 0.85);
  --bg-card-subtle: rgba(13, 20, 36, 0.6);
  --bg-card-hover: rgba(24, 34, 56, 0.9);
  --bg-input: #121A2B;
  --bg-canvas: rgba(9, 13, 22, 0.6);

  --border-color: rgba(255, 255, 255, 0.08);
  --border-highlight: rgba(0, 240, 255, 0.25);
  --border-amber: rgba(255, 184, 0, 0.25);

  --text-primary: #F0F4F8;
  --text-secondary: #94A3B8;
  --text-muted: #64748B;

  --title-gradient: linear-gradient(135deg, #FFFFFF 0%, #CBD5E1 100%);

  --accent-cyan: #00F0FF;
  --accent-cyan-glow: rgba(0, 240, 255, 0.18);
  --accent-amber: #FFB800;
  --accent-amber-glow: rgba(255, 184, 0, 0.15);
  --accent-red: #F43F5E;

  --shadow-card: 0 10px 30px rgba(0, 0, 0, 0.35);
}

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

body {
  font-family: var(--font-sans);
  background-color: var(--bg-dark);
  color: var(--text-primary);
  line-height: 1.6;
  min-height: 100vh;
  padding: 2rem 1rem;
  background-image: 
    radial-gradient(circle at 15% 15%, var(--accent-cyan-glow) 0%, transparent 40%),
    radial-gradient(circle at 85% 75%, var(--accent-amber-glow) 0%, transparent 40%);
  background-attachment: fixed;
  transition: background-color 0.3s ease, color 0.3s ease;
}

/* Discrete Theme Toggle Button */
.theme-toggle-btn {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  color: var(--text-secondary);
  padding: 0.4rem 0.85rem;
  border-radius: 999px;
  font-size: 0.8rem;
  font-weight: 500;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
  transition: all 0.2s ease;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.04);
}

.theme-toggle-btn:hover {
  background: var(--bg-card-hover);
  color: var(--text-primary);
  border-color: var(--border-highlight);
}

html[data-theme="light"] .moon-icon { display: none; }
html[data-theme="light"] .sun-icon { display: inline-block; color: var(--accent-amber); }

html[data-theme="dark"] .sun-icon { display: none; }
html[data-theme="dark"] .moon-icon { display: inline-block; color: var(--accent-cyan); }

.container {
  max-width: 1200px;
  margin: 0 auto;
}

/* Header Section */
header.app-header {
  margin-bottom: 2.5rem;
  text-align: left;
  border-bottom: 1px solid var(--border-color);
  padding-bottom: 1.5rem;
}

.header-top {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 1rem;
}

.title-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.35rem 0.85rem;
  border-radius: 999px;
  background: var(--accent-cyan-glow);
  border: 1px solid var(--border-highlight);
  color: var(--accent-cyan);
  font-size: 0.8rem;
  font-weight: 600;
  letter-spacing: 0.05em;
  text-transform: uppercase;
}

.title-badge svg {
  width: 14px;
  height: 14px;
  fill: currentColor;
}

h1.app-title {
  font-size: clamp(1.75rem, 4vw, 2.5rem);
  font-weight: 700;
  letter-spacing: -0.02em;
  margin-top: 0.5rem;
  background: var(--title-gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

p.app-subtitle {
  color: var(--text-secondary);
  font-size: 0.95rem;
  max-width: 750px;
  margin-top: 0.5rem;
}

/* Main Dashboard Grid (Desktop Horizontal Split Layout) */
.dashboard-grid {
  display: grid;
  grid-template-columns: 380px 1fr;
  gap: 1.75rem;
  align-items: start;
}

.sidebar-column {
  position: sticky;
  top: 1.5rem;
  z-index: 10;
}

.content-column {
  display: flex;
  flex-direction: column;
  gap: 1.75rem;
  min-width: 0;
}

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

  .sidebar-column {
    position: static;
  }
}

/* Card Styling */
.card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 1.75rem;
  box-shadow: var(--shadow-card);
  backdrop-filter: var(--glass-backdrop);
  position: relative;
  overflow: hidden;
  transition: background-color 0.3s ease, border-color 0.3s ease, box-shadow 0.3s ease;
}

.card-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 1.5rem;
  padding-bottom: 1rem;
  border-bottom: 1px solid var(--border-color);
  flex-wrap: wrap;
  gap: 0.75rem;
}

.card-title {
  font-size: 1.05rem;
  font-weight: 600;
  color: var(--text-primary);
  display: flex;
  align-items: center;
  gap: 0.6rem;
  flex: 1 1 auto;
  min-width: 180px;
}

.card-title svg {
  color: var(--accent-cyan);
}

/* Controls Form */
.input-group {
  margin-bottom: 1.75rem;
}

.input-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 0.6rem;
}

.input-label {
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--text-primary);
  display: flex;
  align-items: center;
  gap: 0.4rem;
}

.input-value-badge {
  font-family: var(--font-mono);
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--accent-cyan);
  background: var(--accent-cyan-glow);
  padding: 0.2rem 0.6rem;
  border-radius: 6px;
  border: 1px solid var(--border-highlight);
}

.input-subtext {
  font-size: 0.78rem;
  color: var(--text-muted);
  margin-top: 0.4rem;
}

/* Custom Range Slider Styling */
.slider-container {
  position: relative;
  display: flex;
  align-items: center;
}

input[type="range"] {
  -webkit-appearance: none;
  appearance: none;
  width: 100%;
  height: 8px;
  background: var(--bg-input);
  border-radius: 999px;
  outline: none;
  border: 1px solid var(--border-color);
  cursor: pointer;
  transition: border-color 0.2s ease;
}

input[type="range"]:focus {
  border-color: var(--accent-cyan);
}

input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none;
  appearance: none;
  width: 22px;
  height: 22px;
  border-radius: 50%;
  background: var(--accent-cyan);
  box-shadow: 0 0 12px var(--accent-cyan-glow);
  cursor: pointer;
  transition: transform 0.15s ease, background 0.15s ease;
}

input[type="range"]::-webkit-slider-thumb:hover {
  transform: scale(1.15);
}

input[type="range"]::-moz-range-thumb {
  width: 22px;
  height: 22px;
  border-radius: 50%;
  background: var(--accent-cyan);
  box-shadow: 0 0 12px var(--accent-cyan-glow);
  border: none;
  cursor: pointer;
  transition: transform 0.15s ease;
}

/* Select Dropdown */
select.custom-select {
  width: 100%;
  appearance: none;
  -webkit-appearance: none;
  -moz-appearance: none;
  background-color: var(--bg-input);
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='16' height='16' viewBox='0 0 24 24' fill='none' stroke='%2364748B' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpolyline points='6 9 12 15 18 9'%3E%3C/polyline%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 0.85rem center;
  background-size: 1rem;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  color: var(--text-primary);
  padding: 0.7rem 2.5rem 0.7rem 0.9rem;
  font-size: 0.88rem;
  font-family: var(--font-sans);
  font-weight: 500;
  outline: none;
  cursor: pointer;
  text-overflow: ellipsis;
  white-space: nowrap;
  overflow: hidden;
  transition: border-color 0.2s ease, box-shadow 0.2s ease;
}

[data-theme="dark"] select.custom-select {
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='16' height='16' viewBox='0 0 24 24' fill='none' stroke='%2394A3B8' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpolyline points='6 9 12 15 18 9'%3E%3C/polyline%3E%3C/svg%3E");
}

select.custom-select:focus {
  border-color: var(--accent-cyan);
  box-shadow: 0 0 0 3px var(--accent-cyan-glow);
}

select.custom-select option {
  background: var(--bg-card);
  color: var(--text-primary);
  padding: 0.5rem;
}

/* Metrics Grid Output */
.metrics-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1rem;
  margin-bottom: 1.5rem;
}

@media (max-width: 600px) {
  .metrics-grid {
    grid-template-columns: 1fr;
  }
}

.metric-card {
  background: var(--bg-card-subtle);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 1.25rem;
  transition: all 0.2s ease;
}

.metric-card:hover {
  border-color: var(--border-highlight);
  background: var(--bg-card-hover);
}

.metric-card.highlight {
  border-color: var(--border-highlight);
  background: var(--accent-cyan-glow);
}

.metric-title {
  font-size: 0.8rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--text-secondary);
  margin-bottom: 0.5rem;
}

.metric-value-container {
  display: flex;
  align-items: baseline;
  gap: 0.4rem;
}

.metric-value {
  font-family: var(--font-mono);
  font-size: 1.75rem;
  font-weight: 700;
  color: var(--text-primary);
  line-height: 1.2;
}

.metric-unit {
  font-size: 0.85rem;
  color: var(--text-muted);
  font-weight: 500;
}

.metric-footer {
  font-size: 0.78rem;
  color: var(--text-muted);
  margin-top: 0.5rem;
}

.metric-footer strong {
  color: var(--text-primary);
}

/* Photobiological Milestone Timeline Card */
.timeline-card {
  background: var(--bg-card-subtle);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 1.5rem;
  margin-top: 1.5rem;
}

.timeline-header {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin-bottom: 1.25rem;
}

.timeline-title {
  font-size: 1.05rem;
  font-weight: 600;
  color: var(--text-primary);
}

.timeline-subtitle {
  font-size: 0.8rem;
  color: var(--text-muted);
  margin-top: 0.2rem;
}

.timeline-status-badge {
  font-size: 0.78rem;
  font-family: var(--font-mono);
  font-weight: 600;
  color: var(--accent-amber);
  background: var(--accent-amber-glow);
  padding: 0.25rem 0.75rem;
  border-radius: 999px;
  border: 1px solid var(--border-amber);
}

/* Multi-stage Segmented Bar */
.segmented-timeline-bar {
  display: flex;
  height: 28px;
  background: var(--bg-input);
  border-radius: 8px;
  overflow: hidden;
  border: 1px solid var(--border-color);
  margin-bottom: 1.25rem;
}

.segment-fill {
  display: flex;
  align-items: center;
  justify-content: center;
  height: 100%;
  font-size: 0.72rem;
  font-weight: 600;
  font-family: var(--font-mono);
  white-space: nowrap;
  padding: 0 0.5rem;
  transition: width 0.3s ease;
  overflow: hidden;
}

.segment-fill.safe {
  background: rgba(16, 185, 129, 0.22);
  color: #059669;
  border-right: 2px solid #10B981;
}

html[data-theme="dark"] .segment-fill.safe {
  color: #34D399;
}

.segment-fill.caution {
  background: var(--accent-amber-glow);
  color: var(--accent-amber);
  border-right: 2px solid var(--accent-amber);
}

.segment-fill.plateau {
  background: var(--accent-cyan-glow);
  color: var(--accent-cyan);
}

/* 3 Milestone Metric Boxes Grid */
.milestones-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1rem;
}

@media (max-width: 700px) {
  .milestones-grid {
    grid-template-columns: 1fr;
  }
}

.milestone-box {
  display: flex;
  align-items: center;
  gap: 0.85rem;
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  padding: 0.85rem 1rem;
}

.milestone-box.amber {
  border-color: var(--border-amber);
}

.milestone-box.emerald {
  border-color: rgba(16, 185, 129, 0.3);
}

.milestone-box.cyan {
  border-color: var(--border-highlight);
}

.milestone-icon {
  width: 32px;
  height: 32px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}

.milestone-box.amber .milestone-icon {
  background: var(--accent-amber-glow);
  color: var(--accent-amber);
}

.milestone-box.emerald .milestone-icon {
  background: rgba(16, 185, 129, 0.12);
  color: var(--accent-emerald);
}

.milestone-box.cyan .milestone-icon {
  background: var(--accent-cyan-glow);
  color: var(--accent-cyan);
}

.milestone-label {
  font-size: 0.72rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  color: var(--text-secondary);
}

.milestone-value {
  font-family: var(--font-mono);
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--text-primary);
}

.milestone-subtext {
  font-size: 0.72rem;
  color: var(--text-muted);
}

.timeline-pin.pin-cyan .pin-badge {
  color: var(--accent-cyan);
  border-color: var(--border-highlight);
}

.timeline-scale {
  display: flex;
  justify-content: space-between;
  font-size: 0.72rem;
  font-family: var(--font-mono);
  color: var(--text-muted);
  margin-top: 0.5rem;
}

/* Comparative Ratio Badges Stack */
.ratio-badges-stack {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 0.25rem;
  white-space: nowrap;
}

.ratio-badge-item {
  font-family: var(--font-mono);
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--accent-amber);
  display: flex;
  align-items: center;
  gap: 0.35rem;
}

.ratio-badge-item.purple {
  color: #8B5CF6;
}

[data-theme="dark"] .ratio-badge-item.purple {
  color: #C084FC;
}

.ratio-time-badge {
  font-size: 0.82rem;
  font-weight: 600;
  color: var(--accent-amber);
  opacity: 0.85;
  font-family: var(--font-mono);
  white-space: nowrap;
}

.ratio-time-badge.purple {
  color: #8B5CF6;
}

[data-theme="dark"] .ratio-time-badge.purple {
  color: #C084FC;
}

/* Photobiological Kinetic & Dose Curves Section */
.charts-section {
  margin-top: 0;
}

.section-title {
  font-size: 1.15rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 1.25rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.charts-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.75rem;
}

.chart-card {
  padding: 1.25rem;
}

.chart-legend {
  display: flex;
  align-items: center;
  gap: 0.85rem;
  font-size: 0.78rem;
  white-space: nowrap;
  flex-wrap: nowrap;
  margin-left: auto;
}

.legend-item {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  color: var(--text-muted);
  font-weight: 500;
  white-space: nowrap;
}

.legend-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  display: inline-block;
}

.legend-item.cyan .legend-dot { background: var(--accent-cyan); box-shadow: 0 0 6px var(--accent-cyan-glow); }
.legend-item.amber .legend-dot { background: var(--accent-amber); box-shadow: 0 0 6px var(--accent-amber-glow); }
.legend-item.red .legend-dot { background: var(--accent-red); box-shadow: 0 0 6px rgba(220, 38, 38, 0.3); }
.legend-item.purple .legend-dot { background: #8B5CF6; box-shadow: 0 0 6px rgba(139, 92, 246, 0.4); }

.input-value-badge.purple,
.metric-value.purple {
  color: #8B5CF6;
}

[data-theme="dark"] .input-value-badge.purple,
[data-theme="dark"] .metric-value.purple {
  color: #C084FC;
}

.metric-value.red {
  color: #F43F5E;
}

[data-theme="dark"] .metric-value.red {
  color: #FB7185;
}

.metric-card.purple-card {
  border-color: rgba(139, 92, 246, 0.3);
  background: linear-gradient(135deg, var(--bg-card) 0%, rgba(139, 92, 246, 0.05) 100%);
}

.metric-card.exceeded-card {
  border-color: rgba(244, 63, 94, 0.4);
  background: linear-gradient(135deg, var(--bg-card) 0%, rgba(244, 63, 94, 0.08) 100%);
}

.chart-card canvas {
  width: 100%;
  height: 320px;
  display: block;
  background: var(--bg-canvas);
  border-radius: var(--radius-sm);
  border: 1px solid var(--border-color);
  margin-top: 0.75rem;
}

.timeline-card canvas {
  width: 100%;
  height: 160px;
  display: block;
  background: var(--bg-canvas);
  border-radius: var(--radius-sm);
  border: 1px solid var(--border-color);
  margin-top: 0.75rem;
}

.chart-caption {
  font-size: 0.78rem;
  color: var(--text-muted);
  margin-top: 0.75rem;
  line-height: 1.4;
}

/* Photobiological Reference Section */
.info-section {
  margin-top: 3rem;
  border-top: 1px solid var(--border-color);
  padding-top: 2rem;
}

.info-title {
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 1rem;
}

.info-cards-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 1rem;
}

.info-item {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 1.25rem;
  font-size: 0.85rem;
  color: var(--text-secondary);
}

.info-item-header {
  font-weight: 600;
  color: var(--accent-cyan);
  margin-bottom: 0.4rem;
  font-size: 0.9rem;
}

footer.app-footer {
  margin-top: 3rem;
  text-align: center;
  font-size: 0.8rem;
  color: var(--text-muted);
  border-top: 1px solid var(--border-color);
  padding-top: 1.5rem;
}