@charset "UTF-8";
@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700&family=JetBrains+Mono:wght@400;500&display=swap');

/* ═══════════════════════════════════════
   CSS Custom Properties (Design Tokens)
   ═══════════════════════════════════════ */

:root {
  /* Black and White palette */
  --bg-deep: #000000;
  --bg-surface: #0a0a0a;
  --bg-card: #111111;
  --bg-elevated: #1a1a1a;
  --bg-header: #000000;

  /* Accent colors */
  --aquamarine: #ffffff;
  --aquamarine-dim: #cccccc;
  --aquamarine-glow: rgba(255, 255, 255, 0.15);
  --turquoise: #eeeeee;
  --teal: #bbbbbb;
  --coral: #ff6b6b;
  --coral-dim: #cc5555;
  --amber: #f0c040;

  /* Text */
  --text-primary: #ffffff;
  --text-secondary: #cccccc;
  --text-muted: #888888;
  --text-accent: #ffffff;

  /* Borders */
  --border-subtle: rgba(255, 255, 255, 0.15);
  --border-medium: rgba(255, 255, 255, 0.3);
  --border-strong: rgba(255, 255, 255, 0.6);

  /* Spacing */
  --content-width: 1000px;
  --page-padding: 30px;

  /* Typography */
  --font-body: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', monospace;

  /* Transitions */
  --transition-fast: 0.15s ease;
  --transition-medium: 0.3s ease;
  --transition-slow: 0.6s ease;
}

/* ═══════════════════════════════════════
   Reset & Base
   ═══════════════════════════════════════ */

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

html, body {
  margin: 0;
  padding: 0;
  font-family: var(--font-body);
  font-size: 17px;
  line-height: 1.7;
  color: var(--text-primary);
  background-color: var(--bg-deep);
  display: flex;
  flex-direction: column;
  min-height: 100vh;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* ═══════════════════════════════════════
   Links
   ═══════════════════════════════════════ */

a {
  color: var(--aquamarine);
  text-decoration: none;
  transition: color var(--transition-fast);
}

a:hover {
  color: var(--turquoise);
  text-decoration: underline;
  text-decoration-color: rgba(255, 255, 255, 0.3);
  text-underline-offset: 3px;
}

/* ═══════════════════════════════════════
   Header
   ═══════════════════════════════════════ */

.wrapper {
  display: flex;
  justify-content: center;
  background: linear-gradient(180deg, var(--bg-header) 0%, var(--bg-deep) 100%);
  border-bottom: 1px solid var(--border-subtle);
}

header {
  width: var(--content-width);
  padding: 10px var(--page-padding);
  display: flex;
  justify-content: center;
  align-items: center;
}

.isInternal .wrapper {
  display: none;
}

.homeButton {
  display: inline-block;
  font-size: 28px;
  line-height: 1;
  color: var(--text-muted);
  margin-bottom: 12px;
  transition: all var(--transition-fast);
  text-decoration: none !important;
  opacity: 1 !important; /* Force visibility */
}

#navBar {
  opacity: 1 !important; /* Force visibility */
}

.homeButton:hover {
  color: var(--aquamarine);
  text-shadow: 0 0 10px var(--aquamarine-glow);
  transform: scale(1.1);
}

header .siteTitle {
  font-size: 18px;
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 2px;
  text-decoration: none;
  color: var(--text-muted);
  transition: all var(--transition-fast);
}

header .siteTitle:hover {
  color: var(--aquamarine);
  text-shadow: 0 0 10px var(--aquamarine-glow);
}

/* ═══════════════════════════════════════
   Nav Bar (Breadcrumbs + Dots)
   ═══════════════════════════════════════ */

nav {
  padding-bottom: 8px;
  margin-bottom: 4px;
  display: flex;
  align-items: baseline;
  gap: 12px;
  border-bottom: 1px solid var(--border-subtle);
}

.isInternal nav {
  border-bottom: none;
}

nav h1 {
  font-size: 14px;
  font-weight: 400;
  color: var(--text-muted);
  margin: 0;
}

nav h1 a {
  color: var(--text-muted);
}

nav h1 a:hover {
  color: var(--aquamarine);
  text-decoration: none;
}

.sequenceDots {
  font-size: 24px;
  letter-spacing: 4px;
  margin-left: auto;
}

.sequenceDots a {
  text-decoration: none;
  color: var(--text-muted);
  transition: color var(--transition-fast);
}

.sequenceDots a:hover {
  cursor: default;
}

.sequenceDots .current,
.sequenceDots a.visited:hover {
  position: relative;
  top: -3px;
  cursor: pointer;
  color: var(--aquamarine);
}

.sequenceDots a.visited {
  color: var(--aquamarine-dim);
}

/* ═══════════════════════════════════════
   Body Layout
   ═══════════════════════════════════════ */

#body {
  flex: 1;
  display: flex;
  justify-content: center;
  align-items: stretch;
}

#content {
  width: var(--content-width);
  padding: 0 var(--page-padding);
}

.isInternal #content {
  padding-top: 15px;
}

/* ═══════════════════════════════════════
   Navigation Areas (Left/Right Margins)
   ═══════════════════════════════════════ */

.navigationArea {
  position: fixed;
  top: 50%;
  transform: translateY(-50%);
  width: 80px;
  height: 200px;
  display: flex;
  z-index: 1000;
}

#leftNavigationArea { left: 20px; }
#rightNavigationArea { right: 20px; }

.navigationArea a {
  flex: 1;
  font-size: 50px;
  font-family: var(--font-mono);
  text-decoration: none;
  color: var(--text-muted);
  background: transparent;
  border: none;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all var(--transition-medium);
}

.navigationArea a:hover {
  color: var(--aquamarine);
  text-shadow: 0 0 20px var(--aquamarine-glow);
  transform: scale(1.2);
  text-decoration: none;
}

/* ═══════════════════════════════════════
   Footer
   ═══════════════════════════════════════ */

footer {
  display: none;
}

.chevron {
  font-family: serif;
  margin-left: 8px;
}

/* ═══════════════════════════════════════
   Typography
   ═══════════════════════════════════════ */

h1, h2, h3 {
  color: var(--text-primary);
  font-weight: 600;
}

h1 { font-size: 28px; margin: 0 0 24px 0; }
h2 { font-size: 22px; margin: 32px 0 16px 0; color: var(--aquamarine); }
h3 { font-size: 18px; margin: 24px 0 12px 0; }

p {
  margin: 0 0 16px 0;
  line-height: 1.7;
}

strong {
  color: var(--aquamarine);
  font-weight: 600;
}

em {
  color: var(--text-secondary);
  font-style: italic;
}

li {
  margin-bottom: 8px;
}

/* ═══════════════════════════════════════
   Equation / Data Displays
   ═══════════════════════════════════════ */

.equation {
  font-family: var(--font-mono);
  font-size: 20px;
  color: var(--aquamarine);
  text-align: center;
  padding: 20px;
  margin: 24px 0;
  background: var(--bg-card);
  border: 1px solid var(--border-medium);
  border-radius: 8px;
  letter-spacing: 1px;
}

.readout {
  font-family: var(--font-mono);
  font-size: 14px;
  color: var(--turquoise);
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: 6px;
  padding: 12px 16px;
  margin: 12px 0;
  display: flex;
  flex-wrap: wrap;
  gap: 16px;
}

.readout-item {
  display: flex;
  align-items: baseline;
  gap: 6px;
}

.readout-label {
  color: var(--text-muted);
  font-size: 12px;
  text-transform: uppercase;
  letter-spacing: 1px;
}

.readout-value {
  color: var(--aquamarine);
  font-weight: 500;
  font-size: 16px;
}

/* ═══════════════════════════════════════
   Page Layout (Two-Column)
   ═══════════════════════════════════════ */

.page {
  display: flex;
  justify-content: center;
  gap: 50px;
  align-items: flex-start;
  max-width: var(--content-width);
  margin: 0 auto;
}

.twoColumn {
  width: 480px;
  flex-shrink: 0;
}

/* Make the right column sticky */
.page > .twoColumn:last-child {
  position: sticky;
  top: 0; /* Start at the very top */
  display: flex;
  flex-direction: column;
  gap: 16px;
  padding-top: 10px;
}

.threeColumn {
  width: 270px;
}

.flex {
  display: flex;
  justify-content: space-between;
  gap: 24px;
}

/* ═══════════════════════════════════════
   Simulation Container
   ═══════════════════════════════════════ */

.simulation {
  margin-bottom: 16px;
}

canvas {
  display: block;
  max-width: 100%;
  height: auto !important; /* Allow aspect ratio scaling if inline styles restrict it */
  margin: 0 auto;
  border-radius: 8px;
  border: 1px solid var(--border-medium);
  background: var(--bg-card);
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.3),
              inset 0 0 60px rgba(255, 255, 255, 0.03);
}

canvas:active {
  cursor: default;
  border-color: var(--border-strong);
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.3),
              0 0 15px var(--aquamarine-glow);
}

/* ═══════════════════════════════════════
   Controls (Reset, Toolbar)
   ═══════════════════════════════════════ */

.controls {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 8px 0;
}

.controls button,
.navigationBar .navigationButton {
  font-family: var(--font-body);
  font-size: 13px;
  font-weight: 500;
  padding: 6px 14px;
  border: 1px solid var(--border-medium);
  border-radius: 6px;
  background: var(--bg-card);
  color: var(--text-secondary);
  cursor: pointer;
  transition: all var(--transition-fast);
}

.controls button:hover,
.navigationBar .navigationButton:hover {
  background: var(--bg-elevated);
  color: var(--aquamarine);
  border-color: var(--border-strong);
}

.controls button:active,
.navigationBar .navigationButton:active {
  background: var(--aquamarine);
  color: var(--bg-deep);
}

.toolbar select {
  font-family: var(--font-body);
  font-size: 13px;
  padding: 6px 10px;
  border: 1px solid var(--border-medium);
  border-radius: 6px;
  background: var(--bg-card);
  color: var(--text-secondary);
  cursor: pointer;
  outline: none;
  transition: all var(--transition-fast);
}

.toolbar select:hover {
  border-color: var(--border-strong);
  color: var(--aquamarine);
}

.toolbar select:focus {
  border-color: var(--aquamarine);
  box-shadow: 0 0 0 2px var(--aquamarine-glow);
}

/* ═══════════════════════════════════════
   Increment Control (Buttons)
   ═══════════════════════════════════════ */

.increment-control {
  display: flex;
  align-items: center;
  justify-content: space-between;
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: 8px;
  padding: 8px 16px;
  margin: 16px 0;
  max-width: 300px;
}

.control-label {
  font-size: 14px;
  color: var(--text-secondary);
  font-weight: 500;
}

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

.control-buttons button {
  width: 32px;
  height: 32px;
  border-radius: 6px;
  border: 1px solid var(--border-medium);
  background: var(--bg-elevated);
  color: var(--text-primary);
  font-size: 18px;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: all var(--transition-fast);
  line-height: 1;
  padding: 0;
}

.control-buttons button:hover {
  background: var(--aquamarine);
  color: var(--bg-deep);
  border-color: var(--aquamarine);
  transform: translateY(-1px);
}

.control-buttons button:active {
  transform: translateY(1px);
}

.control-buttons button.minus {
  font-weight: 700;
}

.control-buttons button.plus {
  font-weight: 400;
}

/* ═══════════════════════════════════════
   Slider
   ═══════════════════════════════════════ */

.slider {
  display: flex;
  align-items: center;
  gap: 8px;
  margin: 12px 0;
  font-size: 13px;
  color: var(--text-muted);
}

.slider input[type="range"] {
  -webkit-appearance: none;
  appearance: none;
  flex-grow: 1;
  height: 6px;
  background: var(--bg-elevated);
  border-radius: 3px;
  outline: none;
  cursor: pointer;
}

.slider input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none;
  appearance: none;
  width: 20px;
  height: 20px;
  border-radius: 50%;
  background: var(--aquamarine);
  box-shadow: 0 0 8px rgba(255, 255, 255, 0.4);
  cursor: pointer;
  transition: all var(--transition-fast);
}

.slider input[type="range"]::-webkit-slider-thumb:hover {
  transform: scale(1.2);
  box-shadow: 0 0 14px rgba(255, 255, 255, 0.6);
}

.slider input[type="range"]::-moz-range-thumb {
  width: 20px;
  height: 20px;
  border: none;
  border-radius: 50%;
  background: var(--aquamarine);
  box-shadow: 0 0 8px rgba(255, 255, 255, 0.4);
  cursor: pointer;
}

.slider input[type="range"]::-moz-range-track {
  height: 6px;
  background: var(--bg-elevated);
  border-radius: 3px;
  border: none;
}

/* ═══════════════════════════════════════
   Graphs
   ═══════════════════════════════════════ */

.graph {
  margin: 16px 0;
  border-radius: 8px;
  overflow: hidden;
  border: 1px solid var(--border-subtle);
  display: flex;
  flex-direction: column;
}

.graph-title {
  font-family: var(--font-mono);
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: 1px;
  color: var(--text-muted);
  text-align: center;
  padding: 8px 0;
  background: var(--bg-card);
  border-top: 1px solid var(--border-subtle);
}

/* ═══════════════════════════════════════
   Step Log (Progressive Reveal)
   ═══════════════════════════════════════ */

.stepLog {
  position: relative;
}

.stepLog > * {
  margin-top: 0;
  margin-bottom: 16px;
}

.stepLog > * {
  opacity: 0;
  transition: opacity 0.8s ease;
}

.outsideMargin,
.stepLog .incomplete:before,
.stepLog .complete:before {
  position: absolute;
  left: -1.2em;
  font-size: 1.6em;
}

.stepLog .incomplete:before {
  content: "☐";
  color: var(--text-muted);
}

.stepLog .complete:before {
  content: "☑";
  color: var(--aquamarine);
}

.stepLog.isCompleted:after {
  content: "●";
  font-size: 32px;
  position: absolute;
  left: 50%;
  color: var(--aquamarine);
}

/* ═══════════════════════════════════════
   Sequence Link (Chapter Thumbnails)
   ═══════════════════════════════════════ */

.sequenceLink {
  display: flex;
  flex-direction: column;
  align-items: center;
  margin-bottom: 24px;
  padding: 20px;
  border-radius: 12px;
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  transition: all var(--transition-medium);
}

.sequenceLink:hover {
  border-color: var(--border-medium);
  box-shadow: 0 4px 20px rgba(255, 255, 255, 0.08);
  transform: translateY(-2px);
}

.sequenceLink a {
  text-decoration: none;
}

/* ═══════════════════════════════════════
   Utility Classes
   ═══════════════════════════════════════ */

.hidden {
  display: none;
}

.disabled {
  opacity: 0.4;
  pointer-events: none;
}

.centerContent {
  display: flex;
  align-items: center;
  justify-content: center;
}

input {
  font-size: 16px;
  font-family: var(--font-body);
}

/* ═══════════════════════════════════════
   Pulsing Animation (Reset Reminder)
   ═══════════════════════════════════════ */

.pulsing {
  position: relative;
}

.pulsing:after {
  content: "";
  position: absolute;
  display: block;
  z-index: -1;
  width: 120%;
  height: 120%;
  border-radius: 8px;
  left: -10%;
  top: -10%;
  animation-duration: 2s;
  animation-name: pulse;
  animation-iteration-count: infinite;
  animation-timing-function: ease-in-out;
  animation-direction: alternate;
}

@keyframes pulse {
  from { background-color: transparent; }
  to { background-color: rgba(255, 255, 255, 0.2); }
}

/* ═══════════════════════════════════════
   Landing Page Hero
   ═══════════════════════════════════════ */

.hero-section {
  text-align: center;
  padding: 40px 0 20px;
}

.hero-section h1 {
  font-size: 42px;
  font-weight: 700;
  color: var(--aquamarine);
  margin-bottom: 8px;
  letter-spacing: -1px;
}

.hero-section .tagline {
  font-size: 18px;
  color: var(--text-secondary);
  font-weight: 300;
  margin-bottom: 32px;
}

.concept-card {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: 12px;
  padding: 20px;
  text-align: center;
  transition: all var(--transition-medium);
}

.concept-card:hover {
  border-color: var(--border-medium);
  transform: translateY(-3px);
  box-shadow: 0 8px 30px rgba(0, 0, 0, 0.3);
}

.concept-card h3 {
  color: var(--aquamarine);
  margin-top: 8px;
  font-size: 16px;
}

.concept-card p {
  color: var(--text-secondary);
  font-size: 14px;
  margin-bottom: 0;
}

/* ═══════════════════════════════════════
   Chapter Navigation Cards
   ═══════════════════════════════════════ */

.chapter-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 20px;
  margin: 32px 0;
}

.chapter-card {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: 12px;
  padding: 24px;
  transition: all var(--transition-medium);
  cursor: pointer;
  text-decoration: none;
  display: block;
}

.chapter-card:hover {
  border-color: var(--aquamarine);
  box-shadow: 0 0 20px var(--aquamarine-glow);
  transform: translateY(-2px);
  text-decoration: none;
}

.chapter-card .chapter-number {
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 2px;
  margin-bottom: 8px;
}

.chapter-card h3 {
  color: var(--aquamarine);
  margin: 0 0 8px 0;
  font-size: 18px;
}

.chapter-card p {
  color: var(--text-secondary);
  font-size: 14px;
  margin: 0;
  line-height: 1.5;
}

/* ═══════════════════════════════════════
   Responsive
   ═══════════════════════════════════════ */

@media (max-width: 1000px) {
  :root {
    --content-width: 100%;
    --page-padding: 24px;
  }

  .page {
    flex-direction: column;
  }

  .twoColumn {
    width: 100%;
  }

  .threeColumn {
    width: 100%;
  }

  .flex {
    flex-direction: column;
  }

  .chapter-grid {
    grid-template-columns: 1fr;
  }

  .navigationArea {
    display: none;
  }

  header .siteTitle {
    font-size: 22px;
  }
}

/* Simulation Note */
.simulation-note {
  font-size: 14px;
  color: var(--text-muted);
  border-left: 2px solid var(--border-medium);
  padding-left: 16px;
  margin: 24px 0;
  opacity: 1 !important; /* Ensure visibility in progressive reveal */
}

.next-page-prompt {
  margin-top: 40px !important;
  padding-top: 20px;
  border-top: 1px solid var(--border-subtle);
  color: var(--text-secondary);
  font-style: italic;
  opacity: 1 !important;
}