/* ============================================================================
   CSS Custom Properties — Themes
   ============================================================================ */

/* Dark Theme (Default) */
:root,
[data-theme="dark"] {
  --bg-primary: #1a1a2e;
  --bg-secondary: #252545;
  --bg-tertiary: #2a2a4a;
  --bg-input: #252545;
  --text-primary: #e0e0e0;
  --text-secondary: #888;
  --text-muted: #666;
  --accent-blue: #7ec8e3;
  --accent-purple: #c8a8ea;
  --accent-green: #7ce88c;
  --accent-yellow: #e8c87c;
  --accent-red: #e87c7c;
  --border-color: #2a2a4a;
  --border-active: #4a4a7a;
  --input-border: #3a3a5a;
  --focus-ring: rgba(126, 200, 227, 0.6);
  --error-bg: rgba(232, 124, 124, 0.1);
  --error-border: #e87c7c;
  /* Tutorial theme tokens */
  --tutorial-callout-bg: linear-gradient(135deg, #2a2048 0%, #1e1838 100%);
  --tutorial-callout-shadow: rgba(139, 92, 246, 0.25);
  --tutorial-experiment-bg: linear-gradient(135deg, #2a2518 0%, #1e1c12 100%);
  --tutorial-experiment-border: #b8860b;
  --tutorial-experiment-btn: #b8860b;
  --tutorial-experiment-btn-hover: #996f09;
  --tutorial-bar-gradient-end: #6b21a8;
  --tutorial-bar-border: rgba(200, 168, 234, 0.3);
}

/* Light Theme */
[data-theme="light"] {
  --bg-primary: #f5f5f8;
  --bg-secondary: #ffffff;
  --bg-tertiary: #eeeef2;
  --bg-input: #ffffff;
  --text-primary: #1a1a2e;
  --text-secondary: #666;
  --text-muted: #999;
  --accent-blue: #2980b9;
  --accent-purple: #8e44ad;
  --accent-green: #27ae60;
  --accent-yellow: #f39c12;
  --accent-red: #e74c3c;
  --border-color: #ddd;
  --border-active: #aaa;
  --input-border: #ccc;
  --focus-ring: rgba(41, 128, 185, 0.4);
  --error-bg: rgba(231, 76, 60, 0.08);
  --error-border: #e74c3c;
  /* Tutorial theme tokens */
  --tutorial-callout-bg: linear-gradient(135deg, #f3e8ff 0%, #e9d5ff 100%);
  --tutorial-callout-shadow: rgba(139, 92, 246, 0.15);
  --tutorial-experiment-bg: linear-gradient(135deg, #fef3c7 0%, #fde68a 100%);
  --tutorial-experiment-border: #f59e0b;
  --tutorial-experiment-btn: #f59e0b;
  --tutorial-experiment-btn-hover: #d97706;
  --tutorial-bar-gradient-end: #9333ea;
  --tutorial-bar-border: rgba(147, 51, 234, 0.3);
}

/* High Contrast Theme */
[data-theme="high-contrast"] {
  --bg-primary: #000000;
  --bg-secondary: #111111;
  --bg-tertiary: #1a1a1a;
  --bg-input: #111111;
  --text-primary: #ffffff;
  --text-secondary: #cccccc;
  --text-muted: #aaaaaa;
  --accent-blue: #66ccff;
  --accent-purple: #cc99ff;
  --accent-green: #66ff99;
  --accent-yellow: #ffcc66;
  --accent-red: #ff6666;
  --border-color: #555555;
  --border-active: #ffffff;
  --input-border: #777777;
  --focus-ring: rgba(255, 255, 255, 0.8);
  --error-bg: rgba(255, 102, 102, 0.2);
  --error-border: #ff6666;
  /* Tutorial theme tokens */
  --tutorial-callout-bg: linear-gradient(135deg, #1a0033 0%, #0d001a 100%);
  --tutorial-callout-shadow: rgba(204, 153, 255, 0.35);
  --tutorial-experiment-bg: linear-gradient(135deg, #1a1500 0%, #0d0b00 100%);
  --tutorial-experiment-border: #ffcc66;
  --tutorial-experiment-btn: #ffcc66;
  --tutorial-experiment-btn-hover: #e6b84d;
  --tutorial-bar-gradient-end: #9933ff;
  --tutorial-bar-border: rgba(204, 153, 255, 0.5);
  font-size: 1.1em;
}

/* ============================================================================
   Global Reset & Base
   ============================================================================ */

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

body {
  font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  background: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.5;
}

#app {
  display: flex;
  flex-direction: column;
  min-block-size: 100vh;
}

/* ============================================================================
   Accessibility — Skip Navigation
   ============================================================================ */

.skip-nav {
  position: absolute;
  inset-block-start: -9999px;
  inset-inline-start: -9999px;
  padding: 8px 16px;
  background: var(--accent-blue);
  color: var(--bg-primary);
  text-decoration: none;
  border-radius: 4px;
  font-weight: 600;
  z-index: 9999;
}

.skip-nav:focus {
  inset-block-start: 8px;
  inset-inline-start: 8px;
}

/* ============================================================================
   Top Bar
   ============================================================================ */

#top-bar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding-block: 12px;
  padding-inline: 20px;
  border-block-end: 1px solid var(--border-color);
  background: var(--bg-secondary);
  flex-wrap: wrap;
  gap: 12px;
}

.top-bar-left {
  display: flex;
  align-items: baseline;
  gap: 12px;
}

.app-title {
  font-weight: 700;
  font-size: 16px;
  color: var(--accent-blue);
}

.app-subtitle {
  font-size: 13px;
  color: var(--text-secondary);
}

.top-bar-center {
  display: flex;
  align-items: center;
  gap: 16px;
}

.scenario-name-input {
  background: var(--bg-input);
  border: 1px solid var(--input-border);
  color: var(--text-primary);
  padding-block: 6px;
  padding-inline: 10px;
  border-radius: 4px;
  font-size: 14px;
  inline-size: 200px;
}

.scenario-name-input:focus-visible {
  outline: 2px solid var(--focus-ring);
  outline-offset: 2px;
}

.btn-save {
  background: var(--accent-blue);
  color: var(--bg-primary);
  font-weight: 600;
  border-color: var(--accent-blue);
  white-space: nowrap;
}

.btn-save:hover {
  opacity: 0.85;
}

.iterations-label {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 14px;
  color: var(--text-secondary);
}

.iterations-label input {
  background: var(--bg-input);
  border: 1px solid var(--input-border);
  color: var(--text-primary);
  padding-block: 6px;
  padding-inline: 8px;
  border-radius: 4px;
  font-size: 14px;
  inline-size: 80px;
}

.iterations-label input:focus-visible {
  outline: 2px solid var(--focus-ring);
  outline-offset: 2px;
}

.top-bar-right {
  display: flex;
  align-items: center;
  gap: 8px;
}

.top-bar-btn {
  background: var(--bg-tertiary);
  border: 1px solid var(--border-color);
  color: var(--text-primary);
  padding-block: 6px;
  padding-inline: 12px;
  border-radius: 4px;
  font-size: 14px;
  cursor: pointer;
  transition: background 0.2s, border-color 0.2s;
}

.top-bar-btn:hover {
  background: var(--bg-input);
  border-color: var(--border-active);
}

.top-bar-btn:focus-visible {
  outline: 2px solid var(--focus-ring);
  outline-offset: 2px;
}

.btn-small {
  background: var(--bg-tertiary);
  border: 1px solid var(--border-color);
  color: var(--text-primary);
  padding-block: 4px;
  padding-inline: 10px;
  border-radius: 4px;
  font-size: 13px;
  cursor: pointer;
  transition: background 0.2s, border-color 0.2s;
}

.btn-small:hover {
  background: var(--bg-input);
  border-color: var(--border-active);
}

.btn-small:focus-visible {
  outline: 2px solid var(--focus-ring);
  outline-offset: 2px;
}

/* ============================================================================
   Scenarios Dropdown
   ============================================================================ */

.scenarios-wrapper {
  position: relative;
}

.scenarios-dropdown {
  position: absolute;
  inset-block-start: calc(100% + 4px);
  inset-inline-end: 0;
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: 4px;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.3);
  z-index: 50;
  min-inline-size: 280px;
  max-block-size: 400px;
  overflow-y: auto;
}

.scenarios-dropdown[hidden] {
  display: none;
}

#scenarios-list {
  padding: 4px;
}

.scenario-item {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding-block: 8px;
  padding-inline: 10px;
  border-radius: 4px;
  cursor: pointer;
  transition: background 0.2s;
}

.scenario-item:hover {
  background: var(--bg-tertiary);
}

.scenario-item:focus-visible {
  outline: 2px solid var(--focus-ring);
  outline-offset: -2px;
}

.scenario-name {
  font-size: 14px;
  color: var(--text-primary);
  font-weight: 500;
}

.example-badge {
  display: inline-block;
  font-size: 10px;
  padding-block: 2px;
  padding-inline: 6px;
  border-radius: 3px;
  background: var(--bg-tertiary);
  color: var(--text-muted);
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.scenario-date {
  font-size: 12px;
  color: var(--text-muted);
  margin-block-start: 2px;
}

.scenario-delete {
  background: transparent;
  border: none;
  color: var(--accent-red);
  cursor: pointer;
  padding-block: 8px;
  padding-inline: 12px;
  border-radius: 4px;
  font-size: 14px;
  opacity: 0.7;
  transition: opacity 0.2s, background 0.2s;
}

.scenario-delete:hover {
  opacity: 1;
  background: var(--error-bg);
}

.scenario-delete:focus-visible {
  outline: 2px solid var(--focus-ring);
  outline-offset: 2px;
}

.scenarios-actions {
  padding: 8px;
  border-block-start: 1px solid var(--border-color);
}

.scenarios-actions button {
  inline-size: 100%;
}

/* ============================================================================
   Panels Layout
   ============================================================================ */

#panels {
  display: flex;
  flex: 1;
}

#input-panel {
  flex: 45;
  min-inline-size: 0;
  border-inline-end: 1px solid var(--border-color);
  padding: 20px;
  overflow-y: auto;
}

#results-panel {
  flex: 55;
  min-inline-size: 0;
  padding: 20px;
  overflow-y: auto;
}

/* ============================================================================
   Factor Tree
   ============================================================================ */

.tree-toolbar {
  display: flex;
  justify-content: flex-end;
  margin-block-end: 12px;
}

.btn-expand-all {
  font-size: 12px;
}

.factor-item {
  margin-block-end: 12px;
  border: 1px solid var(--border-color);
  border-radius: 6px;
  padding: 12px;
  background: var(--bg-secondary);
  margin-inline-start: calc(var(--depth, 0) * 16px);
}

.factor-header {
  display: flex;
  align-items: center;
  gap: 8px;
  margin-block-end: 8px;
}

.expand-toggle {
  background: transparent;
  border: none;
  color: var(--text-secondary);
  cursor: pointer;
  padding: 0;
  font-size: 14px;
  inline-size: 44px;
  block-size: 44px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border-radius: 3px;
  transition: background 0.2s;
}

.expand-toggle:hover {
  background: var(--bg-tertiary);
}

.expand-toggle:focus-visible {
  outline: 2px solid var(--focus-ring);
  outline-offset: 2px;
}

.factor-label {
  font-weight: 600;
  font-size: 15px;
  color: var(--text-primary);
  flex: 1;
}

.factor-unit {
  font-size: 13px;
  color: var(--text-muted);
  font-style: italic;
}

.factor-description {
  font-size: 12px;
  line-height: 1.5;
  color: var(--text-secondary);
  margin-block: 4px 8px;
  padding-inline-start: 28px;
}

.factor-references {
  white-space: nowrap;
}

.factor-references a {
  color: var(--accent);
  text-decoration: none;
  border-bottom: 1px dotted var(--accent);
}

.factor-references a:hover {
  border-bottom-style: solid;
}

.factor-references a:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 1px;
  border-radius: 2px;
}

.factor-children {
  margin-block-start: 8px;
}

.factor-children[hidden] {
  display: none;
}

.ci-input-row {
  display: flex;
  align-items: center;
  gap: 8px;
  margin-block-end: 6px;
}

.ci-label {
  font-size: 13px;
  color: var(--text-secondary);
  inline-size: 80px;
}

.ci-input {
  background: var(--bg-input);
  border: 1px solid var(--input-border);
  color: var(--text-primary);
  padding-block: 4px;
  padding-inline: 8px;
  border-radius: 4px;
  font-size: 14px;
  inline-size: 100px;
}

.ci-input:focus-visible {
  outline: 2px solid var(--focus-ring);
  outline-offset: 2px;
}

.ci-input.input-error {
  border-color: var(--error-border);
  background: var(--error-bg);
}

/* PERT Input Row (3-field: min/mode/max) */
.pert-input-row {
  display: flex;
  align-items: center;
  gap: 8px;
  margin-block-end: 6px;
}

.pert-label {
  font-size: 13px;
  color: var(--text-secondary);
  inline-size: 60px;
}

.pert-input {
  background: var(--bg-input);
  border: 1px solid var(--input-border);
  color: var(--text-primary);
  padding-block: 4px;
  padding-inline: 8px;
  border-radius: 4px;
  font-size: 14px;
  inline-size: 90px;
}

.pert-input:focus-visible {
  outline: 2px solid var(--focus-ring);
  outline-offset: 2px;
}

.pert-input.input-error {
  border-color: var(--error-border);
  background: var(--error-bg);
}

/* Input Mode Segmented Toggle */
.input-mode-toggle {
  display: flex;
  gap: 0;
  border: 1px solid var(--border-color);
  border-radius: 4px;
  overflow: hidden;
}

.mode-btn {
  background: var(--bg-tertiary);
  border: none;
  color: var(--text-secondary);
  padding-block: 5px;
  padding-inline: 14px;
  font-size: 12px;
  font-weight: 500;
  cursor: pointer;
  transition: background 0.15s, color 0.15s;
}

.mode-btn:not(:last-child) {
  border-inline-end: 1px solid var(--border-color);
}

.mode-btn.active {
  background: var(--accent-blue);
  color: var(--bg-primary);
  font-weight: 600;
}

.mode-btn:focus-visible {
  outline: 2px solid var(--focus-ring);
  outline-offset: -2px;
}

/* ============================================================================
   Results Panel
   ============================================================================ */

.results-section {
  margin-block-end: 32px;
}

.results-section[hidden] {
  display: none;
}

.section-title {
  font-size: 18px;
  font-weight: 600;
  color: var(--text-primary);
  margin-block-end: 12px;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.chart-controls {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-block-end: 8px;
}

.scale-toggle {
  display: flex;
  gap: 0;
  border: 1px solid var(--border-color);
  border-radius: 4px;
  overflow: hidden;
}

.scale-btn {
  background: var(--bg-tertiary);
  border: none;
  color: var(--text-secondary);
  padding-block: 5px;
  padding-inline: 14px;
  font-size: 12px;
  font-weight: 500;
  cursor: pointer;
  transition: background 0.15s, color 0.15s;
}

.scale-btn:not(:last-child) {
  border-inline-end: 1px solid var(--border-color);
}

.scale-btn.active {
  background: var(--accent-blue);
  color: var(--bg-primary);
  font-weight: 600;
}

.scale-btn:focus-visible {
  outline: 2px solid var(--focus-ring);
  outline-offset: -2px;
}

.export-buttons {
  display: flex;
  gap: 8px;
}

.chart-container {
  inline-size: 100%;
  block-size: 280px;
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: 6px;
}

.stats-cards {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(120px, 1fr));
  gap: 12px;
}

.stat-card {
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: 6px;
  padding: 12px;
}

.stat-label {
  font-size: 12px;
  color: var(--text-secondary);
  margin-block-end: 4px;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.stat-value {
  font-size: 18px;
  font-weight: 600;
  color: var(--text-primary);
}

/* ============================================================================
   Breakdown Table
   ============================================================================ */

.breakdown-table {
  inline-size: 100%;
  border-collapse: collapse;
  font-size: 14px;
}

.breakdown-row {
  border-block-end: 1px solid var(--border-color);
}

.breakdown-row:last-child {
  border-block-end: none;
}

.breakdown-name {
  padding-block: 10px;
  padding-inline: 4px 12px;
  white-space: nowrap;
  font-weight: 500;
  color: var(--text-primary);
}

.breakdown-bar-cell {
  padding-block: 10px;
  padding-inline: 4px;
  inline-size: 50%;
}

.breakdown-bar {
  block-size: 18px;
  border-radius: 3px;
  min-inline-size: 4px;
  transition: inline-size 0.3s ease;
}

.breakdown-value {
  padding-block: 10px;
  padding-inline: 8px 4px;
  text-align: end;
  white-space: nowrap;
  font-weight: 600;
  color: var(--text-primary);
}

.breakdown-pct {
  padding-block: 10px;
  padding-inline: 4px;
  text-align: end;
  white-space: nowrap;
  color: var(--text-secondary);
  font-size: 13px;
}

.color-dot {
  display: inline-block;
  inline-size: 12px;
  block-size: 12px;
  border-radius: 50%;
  margin-inline-end: 8px;
  vertical-align: middle;
}

.text-end {
  text-align: end;
}

.text-secondary {
  color: var(--text-secondary);
}

/* ============================================================================
   Simulating Indicator
   ============================================================================ */

.simulating {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 16px;
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: 6px;
  margin-block-end: 16px;
  color: var(--text-primary);
  font-size: 14px;
}

.simulating[hidden] {
  display: none;
}

.spinner {
  display: inline-block;
  inline-size: 16px;
  block-size: 16px;
  border: 3px solid var(--border-color);
  border-block-start-color: var(--accent-blue);
  border-radius: 50%;
  animation: spinner-rotate 0.8s linear infinite;
}

@keyframes spinner-rotate {
  to {
    transform: rotate(360deg);
  }
}

.simulation-error {
  padding: 16px;
  background: var(--error-bg);
  border: 1px solid var(--error-border);
  border-radius: 6px;
  color: var(--accent-red);
  font-size: 14px;
  margin-block-end: 16px;
}

.simulation-error[hidden] {
  display: none;
}

/* ============================================================================
   Responsive Toggle (Mobile)
   ============================================================================ */

.responsive-toggle {
  display: none;
  position: fixed;
  inset-block-end: 0;
  inset-inline: 0;
  background: var(--bg-secondary);
  border-block-start: 2px solid var(--border-color);
  padding: 8px 12px;
  gap: 8px;
  justify-content: stretch;
  z-index: 100;
  box-shadow: 0 -4px 12px rgba(0, 0, 0, 0.3);
}

.toggle-btn {
  flex: 1;
  background: var(--bg-tertiary);
  border: 1px solid var(--border-color);
  color: var(--text-primary);
  padding-block: 10px;
  padding-inline: 16px;
  border-radius: 4px;
  font-size: 14px;
  font-weight: 600;
  cursor: pointer;
  transition: background 0.2s, border-color 0.2s, color 0.2s;
}

.toggle-btn:hover {
  background: var(--bg-input);
  border-color: var(--border-active);
}

.toggle-btn.active {
  background: var(--accent-blue);
  border-color: var(--accent-blue);
  color: var(--bg-primary);
}

.toggle-btn:focus-visible {
  outline: 2px solid var(--focus-ring);
  outline-offset: 2px;
}

/* ============================================================================
   Responsive Layout
   ============================================================================ */

@media (max-width: 899px) {
  #top-bar {
    flex-direction: column;
    align-items: stretch;
  }

  .top-bar-left,
  .top-bar-center,
  .top-bar-right {
    justify-content: center;
  }

  .top-bar-center {
    flex-direction: column;
    align-items: stretch;
  }

  .scenario-name-input {
    inline-size: 100%;
  }

  .iterations-label {
    justify-content: space-between;
  }

  .top-bar-right {
    flex-wrap: wrap;
    justify-content: center;
  }

  #panels {
    flex-direction: column;
  }

  #input-panel {
    inline-size: 100%;
    border-inline-end: none;
    border-block-end: 1px solid var(--border-color);
    padding-block-end: 80px; /* space for fixed toggle bar */
  }

  #results-panel {
    inline-size: 100%;
    display: none; /* hidden by default on mobile, toggled by JS */
    padding-block-end: 80px;
  }

  #results-panel.mobile-visible {
    display: block;
  }

  #input-panel.mobile-hidden {
    display: none;
  }

  .responsive-toggle {
    display: flex;
    position: fixed;
    inset-block-end: 0;
    inset-inline: 0;
  }

  .ci-input-row,
  .pert-input-row {
    flex-wrap: wrap;
  }

  .ci-label {
    inline-size: 100%;
  }

  .ci-input,
  .pert-input {
    flex: 1;
    min-inline-size: 0;
    inline-size: auto;
  }

  .chart-container {
    block-size: min(280px, 50dvb);
  }

  .factor-description {
    padding-inline-start: 0;
  }
}

/* ============================================================================
   Accessibility — Reduced Motion
   ============================================================================ */

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}

/* ============================================================================
   Focus Visible (Accessibility)
   ============================================================================ */

:focus-visible {
  outline: 2px solid var(--focus-ring);
  outline-offset: 2px;
}

button:focus:not(:focus-visible) {
  outline: none;
}

input:focus:not(:focus-visible) {
  outline: none;
}

/* ============================================================================
   Settings Modal
   ============================================================================ */

.modal {
  border: none;
  border-radius: 8px;
  padding: 0;
  max-inline-size: 500px;
  inline-size: 90%;
  background: var(--bg-secondary);
  color: var(--text-primary);
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.3);
}

.modal::backdrop {
  background: rgba(0, 0, 0, 0.5);
  backdrop-filter: blur(4px);
}

.modal-content {
  display: flex;
  flex-direction: column;
}

.modal-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 20px;
  border-block-end: 1px solid var(--border-color);
}

.modal-header h2 {
  margin: 0;
  font-size: 20px;
  font-weight: 600;
}

.btn-close {
  background: transparent;
  border: none;
  color: var(--text-secondary);
  font-size: 28px;
  line-height: 1;
  cursor: pointer;
  padding: 0;
  inline-size: 32px;
  block-size: 32px;
  display: flex;
  align-items: center;
  justify-content: center;
}

.btn-close:hover {
  color: var(--text-primary);
}

.modal-body {
  padding: 20px;
}

.setting-item {
  margin-block-end: 20px;
}

.setting-label {
  display: block;
  font-weight: 600;
  margin-block-end: 8px;
  font-size: 14px;
}

.setting-help {
  display: block;
  font-weight: normal;
  font-size: 13px;
  color: var(--text-secondary);
  margin-block-start: 4px;
}

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

#lambda-slider {
  flex: 1;
  min-inline-size: 200px;
}

#lambda-input {
  inline-size: 80px;
  background: var(--bg-input);
  border: 1px solid var(--input-border);
  color: var(--text-primary);
  padding-block: 6px;
  padding-inline: 10px;
  border-radius: 4px;
  font-size: 14px;
  text-align: center;
}

#lambda-input:focus-visible {
  outline: 2px solid var(--focus-ring);
  outline-offset: 2px;
}

/* ========================================
   Tutorial System Styles
   ======================================== */

.tutorial-mode {
  padding-top: 36px; /* space for fixed chapter bar */
}

.tutorial-mode .tutorial-chapter-bar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  background: linear-gradient(135deg, var(--accent-purple) 0%, var(--tutorial-bar-gradient-end) 100%);
  color: white;
  border-block-end: 2px solid var(--tutorial-bar-border);
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.2);
}

.tutorial-mode .tutorial-chapter-bar-content {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 6px 12px;
}

.tutorial-mode .tutorial-chapter-header {
  display: flex;
  align-items: baseline;
  gap: 8px;
  min-width: 0;
  flex-shrink: 1;
  overflow: hidden;
}

.tutorial-mode .tutorial-title {
  font-weight: 600;
  font-size: 13px;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.tutorial-mode .tutorial-subtitle {
  font-size: 12px;
  opacity: 0.85;
  white-space: nowrap;
}

.tutorial-mode .tutorial-chapter-progress {
  display: flex;
  align-items: center;
  gap: 6px;
  flex-shrink: 0;
}

.tutorial-mode .tutorial-nav-btn {
  background: rgba(255, 255, 255, 0.2);
  border: 1px solid rgba(255, 255, 255, 0.3);
  color: white;
  padding: 2px 8px;
  border-radius: 3px;
  cursor: pointer;
  font-size: 13px;
  line-height: 1;
  transition: background 0.2s;
}

.tutorial-mode .tutorial-nav-btn:hover {
  background: rgba(255, 255, 255, 0.35);
}

.tutorial-mode .tutorial-step-counter {
  font-size: 12px;
  font-weight: 500;
  opacity: 0.9;
  white-space: nowrap;
}

.tutorial-mode .tutorial-chapter-dots {
  display: flex;
  gap: 6px;
  align-items: center;
  margin-inline-start: auto;
  flex-shrink: 0;
}

.tutorial-mode .tutorial-chapter-dot {
  inline-size: 8px;
  block-size: 8px;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.3);
  cursor: pointer;
  transition: all 0.2s;
  border: none;
  padding: 0;
}

.tutorial-mode .tutorial-chapter-dot:hover {
  background: rgba(255, 255, 255, 0.5);
  transform: scale(1.2);
}

.tutorial-mode .tutorial-chapter-dot.active {
  background: white;
  inline-size: 10px;
  block-size: 10px;
}

.tutorial-mode .tutorial-exit-btn {
  background: rgba(239, 68, 68, 0.7);
  border: 1px solid rgba(239, 68, 68, 1);
  color: white;
  padding: 2px 8px;
  border-radius: 3px;
  cursor: pointer;
  font-size: 13px;
  line-height: 1;
  flex-shrink: 0;
  transition: background 0.2s;
}

.tutorial-mode .tutorial-exit-btn:hover {
  background: rgba(239, 68, 68, 0.9);
}

.tutorial-mode .tutorial-chapter-bar .exit-tutorial:hover {
  background: rgba(239, 68, 68, 1);
}

.tutorial-mode .tutorial-callout {
  background: var(--tutorial-callout-bg);
  border: 2px solid var(--accent-purple);
  border-radius: 8px;
  padding: 16px;
  margin-block: 12px;
  box-shadow: 0 4px 12px var(--tutorial-callout-shadow);
  position: relative;
}

.tutorial-mode .tutorial-callout::before {
  content: '';
  position: absolute;
  inset-inline-start: 0;
  inset-block-start: 0;
  inline-size: 4px;
  block-size: 100%;
  background: var(--accent-purple);
  border-start-start-radius: 6px;
  border-end-start-radius: 6px;
}

.tutorial-mode .tutorial-callout-header {
  font-weight: 600;
  color: var(--accent-purple);
  margin-block-end: 8px;
  font-size: 15px;
}

.tutorial-mode .tutorial-callout-content {
  color: var(--text-primary);
  line-height: 1.6;
  font-size: 14px;
}

.tutorial-mode .tutorial-callout-content p {
  margin-block: 8px;
}

.tutorial-mode .tutorial-callout-content p:first-child {
  margin-block-start: 0;
}

.tutorial-mode .tutorial-callout-content p:last-child {
  margin-block-end: 0;
}

.tutorial-mode .tutorial-experiment {
  background: var(--tutorial-experiment-bg);
  border: 2px solid var(--tutorial-experiment-border);
  border-radius: 8px;
  padding: 12px 16px;
  margin-block-start: 12px;
  display: flex;
  align-items: center;
  gap: 12px;
}

.tutorial-mode .tutorial-experiment-icon {
  font-size: 20px;
}

.tutorial-mode .tutorial-experiment-text {
  flex: 1;
  color: var(--text-primary);
  font-size: 14px;
  line-height: 1.5;
}

.tutorial-mode .tutorial-experiment button {
  background: var(--tutorial-experiment-btn);
  border: none;
  color: white;
  padding: 6px 16px;
  border-radius: 4px;
  cursor: pointer;
  font-size: 13px;
  font-weight: 500;
  transition: background 0.2s;
  white-space: nowrap;
}

.tutorial-mode .tutorial-experiment button:hover {
  background: var(--tutorial-experiment-btn-hover);
}

.tutorial-mode .tutorial-active {
  animation: tutorialPulse 2s ease-in-out infinite;
  box-shadow: 0 0 0 3px rgba(139, 92, 246, 0.3);
  border-radius: 4px;
}

@keyframes tutorialPulse {
  0%, 100% {
    box-shadow: 0 0 0 3px rgba(139, 92, 246, 0.3);
  }
  50% {
    box-shadow: 0 0 0 6px rgba(139, 92, 246, 0.5);
  }
}

/* Mobile responsive adjustments */
@media (max-width: 899px) {
  .tutorial-mode .tutorial-chapter-bar {
    flex-wrap: wrap;
    gap: 8px;
  }

  .tutorial-mode .tutorial-chapter-bar .chapter-dots {
    margin-inline-start: 0;
    order: 3;
    flex-basis: 100%;
    justify-content: center;
  }

  .tutorial-mode .tutorial-callout {
    padding: 12px;
  }

  .tutorial-mode .tutorial-experiment {
    flex-direction: column;
    align-items: flex-start;
  }

  .tutorial-mode .tutorial-experiment button {
    align-self: stretch;
  }
}