/* ============================================================
   QUANTUM COMPUTING NOTES — MAIN STYLES
   Aesthetic: "Deep Space Observatory" — dark, precise, scientific
   ============================================================ */

@import url('https://fonts.googleapis.com/css2?family=DM+Serif+Display:ital@0;1&family=Source+Serif+4:ital,opsz,wght@0,8..60,300;0,8..60,400;0,8..60,600;1,8..60,300;1,8..60,400&family=JetBrains+Mono:ital,wght@0,300;0,400;0,700;1,400&display=swap');

/* === CSS VARIABLES === */
:root {
  --bg: #070b14;
  --bg-2: #0d1424;
  --bg-3: #121b2e;
  --surface: #162035;
  --surface-2: #1e2d47;
  --border: #1f3155;
  --border-2: #2a4070;
  --text: #cdd9f0;
  --text-dim: #7a93b8;
  --text-faint: #3d5278;
  --cyan: #00d4ff;
  --cyan-dim: #0099cc;
  --cyan-glow: rgba(0, 212, 255, 0.15);
  --purple: #9b5de5;
  --purple-dim: #6b3fa0;
  --purple-glow: rgba(155, 93, 229, 0.12);
  --gold: #f4c430;
  --gold-dim: #b8900a;
  --gold-glow: rgba(244, 196, 48, 0.1);
  --green: #00e676;
  --red: #ff4f6e;
  --orange: #ff9f43;
  --w1: #00d4ff;
  --w2: #9b5de5;
  --w3: #00e676;
  --w4: #ff9f43;

  --font-display: 'DM Serif Display', Georgia, serif;
  --font-body: 'Source Serif 4', Georgia, serif;
  --font-mono: 'JetBrains Mono', 'Courier New', monospace;

  --radius: 8px;
  --radius-lg: 16px;
  --transition: 0.25s ease;
  --shadow-glow: 0 0 40px rgba(0, 212, 255, 0.08);
}

/* === RESET === */
*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}
html {
  scroll-behavior: smooth;
  font-size: 17px;
}
body {
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-body);
  font-weight: 300;
  line-height: 1.75;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

@media (max-width: 768px) {
  html {
    font-size: 16px;
  }
}
@media (max-width: 480px) {
  html {
    font-size: 15px;
  }
}

/* === NAVIGATION === */
.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: 60px;
  background: rgba(7, 11, 20, 0.92);
  backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--border);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 2rem;
  z-index: 1000;
}
@media (max-width: 768px) {
  .nav {
    padding: 0 1rem;
  }
  .nav-brand-text {
    display: none;
  }
}
.nav-brand {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  text-decoration: none;
  color: var(--text);
}
.nav-brand-icon {
  width: 32px;
  height: 32px;
  background: linear-gradient(135deg, var(--cyan), var(--purple));
  border-radius: 8px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 16px;
  flex-shrink: 0;
}
.nav-brand-text {
  font-family: var(--font-display);
  font-size: 1.1rem;
  letter-spacing: 0.02em;
}
.nav-links {
  display: flex;
  align-items: center;
  gap: 0.25rem;
  list-style: none;
}
.nav-sidebar-toggle {
  display: none;
  align-items: center;
  justify-content: center;
  width: 42px;
  height: 42px;
  border: 1px solid var(--border);
  border-radius: 12px;
  background: rgba(22, 32, 53, 0.9);
  color: var(--text);
  cursor: pointer;
  transition: var(--transition);
  flex-shrink: 0;
}
.nav-sidebar-toggle:hover {
  border-color: var(--border-2);
  background: var(--surface);
}
.nav-sidebar-toggle svg {
  width: 18px;
  height: 18px;
}
.nav-sidebar-toggle-label {
  display: none;
  font-family: var(--font-mono);
  font-size: 0.68rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--text-dim);
}
.mobile-sidebar-backdrop {
  position: fixed;
  inset: 0;
  background: rgba(3, 7, 16, 0.72);
  backdrop-filter: blur(6px);
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.25s ease;
  z-index: 1080;
}
.mobile-sidebar-backdrop.visible {
  opacity: 1;
  pointer-events: auto;
}
@media (max-width: 600px) {
  .nav-links {
    gap: 0.1rem;
  }
  .nav-links a {
    padding: 0.35rem 0.5rem !important;
  }
}
.nav-links a {
  display: flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.35rem 0.8rem;
  border-radius: var(--radius);
  text-decoration: none;
  color: var(--text-dim);
  font-family: var(--font-mono);
  font-size: 0.78rem;
  transition: var(--transition);
  border: 1px solid transparent;
}
@media (max-width: 480px) {
  .nav-links a span:not(.week-dot) {
    display: none;
  }
}
.nav-links a:hover,
.nav-links a.active {
  color: var(--text);
  background: var(--surface);
  border-color: var(--border);
}
.nav-links a.w1.active,
.nav-links a.w1:hover {
  color: var(--w1);
  border-color: rgba(0, 212, 255, 0.3);
}
.nav-links a.w2.active,
.nav-links a.w2:hover {
  color: var(--w2);
  border-color: rgba(155, 93, 229, 0.3);
}
.nav-links a.w3.active,
.nav-links a.w3:hover {
  color: var(--w3);
  border-color: rgba(0, 230, 118, 0.3);
}
.nav-links a.w4.active,
.nav-links a.w4:hover {
  color: var(--w4);
  border-color: rgba(255, 159, 67, 0.3);
}
.week-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  flex-shrink: 0;
}
.w1 .week-dot {
  background: var(--w1);
}
.w2 .week-dot {
  background: var(--w2);
}
.w3 .week-dot {
  background: var(--w3);
}
.w4 .week-dot {
  background: var(--w4);
}

/* === LAYOUT === */
.page-wrapper {
  padding-top: 60px;
  min-height: 100vh;
}

/* === HERO SECTION === */
.hero {
  position: relative;
  padding: 5rem 2rem 4rem;
  text-align: center;
  overflow: hidden;
}
.hero-bg {
  position: absolute;
  inset: 0;
  background:
    radial-gradient(ellipse 60% 50% at 50% 0%, rgba(0, 212, 255, 0.07) 0%, transparent 70%),
    radial-gradient(ellipse 40% 40% at 20% 80%, rgba(155, 93, 229, 0.05) 0%, transparent 60%);
  pointer-events: none;
}
.hero-week-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.4rem 1rem;
  border-radius: 100px;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  margin-bottom: 1.5rem;
  border: 1px solid;
}
.hero-week-badge.w1 {
  background: rgba(0, 212, 255, 0.08);
  border-color: rgba(0, 212, 255, 0.3);
  color: var(--w1);
}
.hero-week-badge.w2 {
  background: rgba(155, 93, 229, 0.08);
  border-color: rgba(155, 93, 229, 0.3);
  color: var(--w2);
}
.hero-week-badge.w3 {
  background: rgba(0, 230, 118, 0.08);
  border-color: rgba(0, 230, 118, 0.3);
  color: var(--w3);
}
.hero-week-badge.w4 {
  background: rgba(255, 159, 67, 0.08);
  border-color: rgba(255, 159, 67, 0.3);
  color: var(--w4);
}
.hero-title {
  font-family: var(--font-display);
  font-size: clamp(2.2rem, 5vw, 3.8rem);
  line-height: 1.15;
  letter-spacing: -0.01em;
  margin-bottom: 1rem;
  background: linear-gradient(135deg, #ffffff 0%, var(--text) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}
.hero-subtitle {
  font-size: 1.1rem;
  color: var(--text-dim);
  max-width: 650px;
  margin: 0 auto 2.5rem;
  font-weight: 300;
}
.hero-toc-preview {
  display: flex;
  justify-content: center;
  flex-wrap: wrap;
  gap: 0.5rem;
  max-width: 800px;
  margin: 0 auto;
}
.toc-pill {
  padding: 0.3rem 0.85rem;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 100px;
  font-size: 0.8rem;
  color: var(--text-dim);
  font-family: var(--font-mono);
  transition: var(--transition);
  text-decoration: none;
}
.toc-pill:hover {
  color: var(--text);
  border-color: var(--border-2);
  background: var(--surface-2);
}

/* === MAIN CONTENT LAYOUT === */
.content-wrapper {
  display: grid;
  grid-template-columns: 260px 1fr;
  max-width: 1300px;
  margin: 0 auto;
  padding: 2rem;
  gap: 3rem;
  align-items: start;
}
@media (max-width: 1100px) {
  .content-wrapper {
    gap: 2rem;
  }
}
@media (max-width: 900px) {
  .content-wrapper {
    grid-template-columns: 1fr;
    padding: 1.5rem 1rem;
  }
}

/* === SIDEBAR === */
.sidebar {
  position: sticky;
  top: 80px;
  max-height: calc(100vh - 100px);
  overflow-y: auto;
  scrollbar-width: none;
}
.sidebar::-webkit-scrollbar {
  display: none;
}
.sidebar-inner {
  background: var(--bg-2);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 1.25rem;
}
.sidebar-title {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--text-faint);
  margin-bottom: 1rem;
  padding-bottom: 0.5rem;
  border-bottom: 1px solid var(--border);
}
.sidebar-nav {
  list-style: none;
}
.sidebar-nav li {
  margin: 0.1rem 0;
}
.sidebar-nav a {
  display: flex;
  align-items: flex-start;
  gap: 0.5rem;
  padding: 0.4rem 0.6rem;
  border-radius: 6px;
  text-decoration: none;
  color: var(--text-dim);
  font-size: 0.82rem;
  line-height: 1.4;
  transition: var(--transition);
  border-left: 2px solid transparent;
}
.sidebar-nav a:hover,
.sidebar-nav a.active {
  color: var(--text);
  background: var(--surface);
  border-left-color: var(--cyan);
}
.sidebar-nav .section-num {
  font-family: var(--font-mono);
  font-size: 0.68rem;
  color: var(--text-faint);
  margin-top: 2px;
  flex-shrink: 0;
}
.sidebar-nav .sub-item a {
  padding-left: 1.5rem;
  font-size: 0.78rem;
}
.sidebar-mobile-header,
.sidebar-week-links,
.sidebar-week-link {
  display: none;
}

/* === ARTICLE === */
.article {
  max-width: 860px;
  min-width: 0;
}

/* === SECTIONS === */
.section {
  margin-bottom: 4rem;
  padding-top: 1rem;
}
.section-header {
  display: flex;
  align-items: center;
  gap: 1rem;
  margin-bottom: 2rem;
  padding-bottom: 1rem;
  border-bottom: 1px solid var(--border);
}
.section-number {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--text-faint);
  flex-shrink: 0;
}
.section-title {
  font-family: var(--font-display);
  font-size: 1.8rem;
  color: #fff;
  line-height: 1.2;
}
.subsection {
  margin: 2.5rem 0;
}
.subsection-title {
  font-family: var(--font-display);
  font-size: 1.25rem;
  color: var(--text);
  margin-bottom: 1rem;
  display: flex;
  align-items: center;
  gap: 0.6rem;
}
.subsection-title::before {
  content: '';
  width: 3px;
  height: 1.2em;
  background: var(--cyan);
  border-radius: 2px;
  flex-shrink: 0;
}
.subsubsection-title {
  font-family: var(--font-body);
  font-size: 1rem;
  font-weight: 600;
  color: var(--text);
  margin: 1.5rem 0 0.75rem;
  letter-spacing: 0.01em;
}

/* === TYPOGRAPHY === */
p {
  margin-bottom: 1rem;
}
p:last-child {
  margin-bottom: 0;
}
strong {
  color: #fff;
  font-weight: 600;
}
em {
  color: var(--text);
  font-style: italic;
}
a {
  color: var(--cyan);
  text-decoration: none;
}
a:hover {
  text-decoration: underline;
}

/* === CALLOUT BOXES === */
.callout {
  background: var(--bg-2);
  border: 1px solid var(--border);
  border-left: 3px solid;
  border-radius: var(--radius);
  padding: 1.25rem 1.5rem;
  margin: 1.5rem 0;
}
.callout-header {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  margin-bottom: 0.75rem;
}
.callout.definition {
  border-left-color: var(--cyan);
}
.callout.definition .callout-header {
  color: var(--cyan);
}
.callout.theorem {
  border-left-color: var(--gold);
}
.callout.theorem .callout-header {
  color: var(--gold);
}
.callout.insight {
  border-left-color: var(--purple);
}
.callout.insight .callout-header {
  color: var(--purple);
}
.callout.warning {
  border-left-color: var(--orange);
}
.callout.warning .callout-header {
  color: var(--orange);
}
.callout.example {
  border-left-color: var(--green);
}
.callout.example .callout-header {
  color: var(--green);
}
.callout.postulate {
  border-left-color: var(--red);
}
.callout.postulate .callout-header {
  color: var(--red);
}

/* === MATH DISPLAY === */
.math-block {
  background: var(--bg-2);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.25rem 1.5rem;
  margin: 1.5rem 0;
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
  text-align: center;
  font-size: 1.05rem;
}
/* Prevent mathjax scale issues from making mobile overflow */
mjx-container[display='true'] {
  overflow-x: auto !important;
  overflow-y: hidden !important;
  max-width: 100% !important;
  padding: 0.5rem 0;
}
@media (max-width: 640px) {
  .math-block {
    padding: 1rem;
    font-size: 0.95rem;
  }
}
.math-label {
  float: right;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--text-faint);
  margin-top: 0.25rem;
}
.math-block.highlighted {
  border-color: var(--cyan-dim);
  background: linear-gradient(135deg, var(--bg-2), rgba(0, 212, 255, 0.03));
  box-shadow: var(--shadow-glow);
}

/* === CODE BLOCKS === */
pre {
  background: var(--bg-2);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.25rem 1.5rem;
  overflow-x: auto;
  margin: 1.5rem 0;
}
code {
  font-family: var(--font-mono);
  font-size: 0.85rem;
  color: var(--cyan);
  background: var(--surface);
  padding: 0.1em 0.4em;
  border-radius: 4px;
}
pre code {
  background: none;
  padding: 0;
  color: var(--text);
  font-size: 0.82rem;
  line-height: 1.7;
}
.code-comment {
  color: var(--text-faint);
  font-style: italic;
}
.code-kw {
  color: var(--purple);
}
.code-str {
  color: var(--green);
}
.code-num {
  color: var(--orange);
}
.code-fn {
  color: var(--cyan);
}

/* === TABLES === */
.table-wrapper {
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
  margin: 1.5rem 0;
  border-radius: var(--radius);
  border: 1px solid var(--border);
}
@media (max-width: 640px) {
  .table-wrapper table {
    font-size: 0.82rem;
  }
  .table-wrapper th,
  .table-wrapper td {
    padding: 0.5rem 0.75rem;
  }
}
table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.9rem;
}
th {
  background: var(--surface);
  padding: 0.75rem 1rem;
  text-align: left;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--text-dim);
  border-bottom: 1px solid var(--border);
}
td {
  padding: 0.65rem 1rem;
  border-bottom: 1px solid var(--border);
  vertical-align: middle;
}
tr:last-child td {
  border-bottom: none;
}
tr:hover td {
  background: var(--surface);
}

/* === VISUALIZATIONS CONTAINER === */
.viz-container {
  background: var(--bg-2);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 0;
  margin: 2rem 0;
  overflow: hidden;
}
.viz-container[data-stable-layout='true'] {
  overflow: hidden;
}
.viz-mobile-viewport {
  width: 100%;
  overflow: hidden;
}
.viz-mobile-stage {
  transform-origin: top left;
  will-change: transform;
}
.viz-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0.85rem 1.25rem;
  border-bottom: 1px solid var(--border);
  background: var(--surface);
}
.viz-title {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  color: var(--text-dim);
  display: flex;
  align-items: center;
  gap: 0.5rem;
}
.viz-title::before {
  content: '⬡';
  color: var(--cyan);
  font-size: 0.9rem;
}
.viz-body {
  padding: 1.5rem;
}
.viz-controls {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  padding: 0.85rem 1.25rem;
  background: var(--surface);
  border-top: 1px solid var(--border);
  align-items: center;
}
@media (max-width: 600px) {
  .viz-controls {
    flex-direction: column;
    align-items: stretch;
    gap: 0.75rem;
    padding: 1rem;
  }
  .ctrl-group {
    justify-content: space-between;
  }
  input[type='range'] {
    width: 140px;
  }
}
@media (max-width: 400px) {
  input[type='range'] {
    width: 100px;
  }
}
.ctrl-group {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}
.ctrl-label {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  color: var(--text-faint);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}
input[type='range'] {
  -webkit-appearance: none;
  appearance: none;
  height: 4px;
  background: var(--border);
  border-radius: 2px;
  outline: none;
  cursor: pointer;
  width: 120px;
}
input[type='range']::-webkit-slider-thumb {
  -webkit-appearance: none;
  appearance: none;
  width: 14px;
  height: 14px;
  background: var(--cyan);
  border-radius: 50%;
  cursor: pointer;
  border: 2px solid var(--bg);
}
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.4rem;
  padding: 0.4rem 1rem;
  border-radius: 6px;
  border: 1px solid var(--border);
  background: var(--surface);
  color: var(--text-dim);
  font-family: var(--font-mono);
  font-size: 0.78rem;
  cursor: pointer;
  transition: var(--transition);
}
.btn:hover {
  color: var(--text);
  border-color: var(--border-2);
  background: var(--surface-2);
}
.btn.primary {
  background: var(--cyan-glow);
  border-color: var(--cyan-dim);
  color: var(--cyan);
}
.btn.primary:hover {
  background: rgba(0, 212, 255, 0.2);
}
select {
  background: var(--surface);
  border: 1px solid var(--border);
  color: var(--text);
  padding: 0.3rem 0.6rem;
  border-radius: 6px;
  font-family: var(--font-mono);
  font-size: 0.78rem;
  cursor: pointer;
  outline: none;
}
@media (max-width: 600px) {
  .btn,
  select {
    font-size: 0.75rem;
    padding: 0.4rem 0.75rem;
  }
}
select:hover {
  border-color: var(--border-2);
}

/* === VALUE DISPLAY === */
.val-display {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  color: var(--cyan);
  min-width: 3rem;
  text-align: right;
}

/* === CIRCUIT GATE STYLES === */
.circuit-svg {
  width: 100%;
  overflow: visible;
}
.gate-box {
  rx: 4;
  ry: 4;
}

/* === STEP INDICATORS === */
.step-indicator {
  display: flex;
  gap: 0.5rem;
  margin-bottom: 1rem;
  flex-wrap: wrap;
}
.step-btn {
  padding: 0.3rem 0.75rem;
  border-radius: 100px;
  border: 1px solid var(--border);
  background: var(--surface);
  color: var(--text-dim);
  font-family: var(--font-mono);
  font-size: 0.72rem;
  cursor: pointer;
  transition: var(--transition);
}
.step-btn.active {
  border-color: var(--cyan-dim);
  color: var(--cyan);
  background: var(--cyan-glow);
}

/* === KEY RESULT HIGHLIGHT === */
.key-result {
  background: linear-gradient(135deg, var(--bg-2), rgba(0, 212, 255, 0.04));
  border: 1px solid var(--cyan-dim);
  border-radius: var(--radius-lg);
  padding: 1.5rem;
  margin: 2rem 0;
  position: relative;
}
.key-result::before {
  content: '★';
  position: absolute;
  top: -0.6rem;
  left: 1rem;
  background: var(--bg);
  padding: 0 0.3rem;
  color: var(--cyan);
  font-size: 0.9rem;
}
.key-result-title {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  color: var(--cyan);
  letter-spacing: 0.1em;
  text-transform: uppercase;
  margin-bottom: 0.75rem;
}

/* === COMPLEXITY TABLE === */
.complexity-row {
  display: grid;
  grid-template-columns: 1fr 1fr 1fr;
  gap: 1rem;
  margin: 1.5rem 0;
}
@media (max-width: 600px) {
  .complexity-row {
    grid-template-columns: 1fr;
    gap: 0.75rem;
  }
}
.complexity-card {
  background: var(--bg-2);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1rem;
  text-align: center;
}
.complexity-label {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  color: var(--text-faint);
  text-transform: uppercase;
  letter-spacing: 0.1em;
  margin-bottom: 0.5rem;
}
.complexity-value {
  font-family: var(--font-display);
  font-size: 1.3rem;
  color: var(--text);
}
.complexity-card.quantum .complexity-value {
  color: var(--cyan);
}
.complexity-card.classical .complexity-value {
  color: var(--text-dim);
}
.complexity-card.speedup .complexity-value {
  color: var(--gold);
}

/* === FOOTER === */
.page-footer {
  margin-top: 6rem;
  padding: 2rem;
  border-top: 1px solid var(--border);
  text-align: center;
  color: var(--text-faint);
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.05em;
}

/* === PROGRESS BAR === */
.reading-progress {
  position: fixed;
  top: 60px;
  left: 0;
  right: 0;
  height: 2px;
  background: var(--border);
  z-index: 999;
}
.reading-progress-bar {
  height: 100%;
  background: linear-gradient(90deg, var(--cyan), var(--purple));
  width: 0%;
  transition: width 0.1s linear;
}

/* === ANIMATIONS === */
@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(16px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}
@keyframes pulse-glow {
  0%,
  100% {
    box-shadow: 0 0 20px rgba(0, 212, 255, 0.1);
  }
  50% {
    box-shadow: 0 0 40px rgba(0, 212, 255, 0.2);
  }
}
.fade-in {
  animation: fadeInUp 0.5s ease both;
  will-change: opacity, transform;
}

/* === KETS === */
.ket {
  font-family: var(--font-mono);
  font-size: 0.95em;
  color: var(--cyan);
  background: rgba(0, 212, 255, 0.08);
  padding: 0.05em 0.3em;
  border-radius: 3px;
}

/* === HIGHLIGHT SPANS === */
.hi-cyan {
  color: var(--cyan);
}
.hi-purple {
  color: var(--purple);
}
.hi-gold {
  color: var(--gold);
}
.hi-green {
  color: var(--green);
}
.hi-red {
  color: var(--red);
}
.hi-orange {
  color: var(--orange);
}

/* === CANVAS === */
canvas {
  display: block;
  border-radius: var(--radius);
}

/* === RESPONSIVE UTILITIES === */
@media (max-width: 900px) {
  html {
    font-size: 15px;
  }
  .hero-title {
    font-size: clamp(2rem, 7vw, 2.65rem);
  }
  .nav {
    gap: 0.75rem;
    padding: 0 0.9rem;
  }
  .nav-sidebar-toggle {
    display: inline-flex;
    gap: 0.45rem;
    width: auto;
    padding: 0 0.8rem;
  }
  .nav-sidebar-toggle-label {
    display: inline;
  }
  .nav-links {
    margin-left: auto;
    gap: 0.2rem;
  }
  .nav-links a {
    padding: 0.38rem 0.55rem;
    font-size: 0.72rem;
  }
  .sidebar {
    display: block;
    position: fixed;
    top: 0;
    left: 0;
    bottom: 0;
    width: min(380px, calc(100vw - 1rem));
    max-height: 100vh;
    padding: 0.75rem;
    overflow: hidden;
    z-index: 1090;
    transform: translateX(calc(-100% - 1rem));
    transition: transform 0.28s ease;
  }
  .sidebar.mobile-open {
    transform: translateX(0);
  }
  .sidebar-inner {
    height: 100%;
    overflow-y: auto;
    padding: 0;
    box-shadow: 0 24px 60px rgba(0, 0, 0, 0.38);
    background:
      linear-gradient(180deg, rgba(22, 32, 53, 0.98), rgba(13, 20, 36, 0.98)),
      var(--bg-2);
  }
  body.sidebar-open {
    overflow: hidden;
  }
  .sidebar-mobile-header {
    position: sticky;
    top: 0;
    z-index: 1;
    padding: 1rem 1rem 0.9rem;
    border-bottom: 1px solid var(--border);
    background: rgba(13, 20, 36, 0.96);
    backdrop-filter: blur(14px);
  }
  .sidebar-mobile-kicker {
    display: block;
    margin-bottom: 0.35rem;
    font-family: var(--font-mono);
    font-size: 0.66rem;
    letter-spacing: 0.14em;
    text-transform: uppercase;
    color: var(--text-faint);
  }
  .sidebar-mobile-title {
    font-family: var(--font-display);
    font-size: 1.45rem;
    line-height: 1.1;
    color: #fff;
  }
  .sidebar-mobile-subtitle {
    margin-top: 0.45rem;
    color: var(--text-dim);
    font-size: 0.9rem;
    line-height: 1.45;
  }
  .sidebar-week-links {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 0.6rem;
    padding: 1rem;
    border-bottom: 1px solid var(--border);
  }
  .sidebar-week-link {
    display: flex;
    align-items: center;
    gap: 0.45rem;
    padding: 0.7rem 0.8rem;
    border-radius: 12px;
    border: 1px solid var(--border);
    background: var(--surface);
    text-decoration: none;
    color: var(--text-dim);
    font-family: var(--font-mono);
    font-size: 0.75rem;
  }
  .sidebar-week-link.active {
    color: var(--text);
    border-color: var(--border-2);
    background: var(--surface-2);
  }
  .sidebar-title {
    padding: 1rem 1rem 0.5rem;
    margin: 0;
  }
  .sidebar-nav {
    padding: 0 0.75rem 1.1rem;
  }
  .sidebar-nav a {
    padding: 0.62rem 0.75rem;
    font-size: 0.86rem;
    border-left: none;
    border: 1px solid transparent;
  }
  .sidebar-nav a:hover,
  .sidebar-nav a.active {
    border-color: var(--border);
    background: var(--surface);
  }
  .sidebar-nav .sub-item a {
    padding-left: 1rem;
    font-size: 0.8rem;
  }
  .content-wrapper {
    padding: 1.25rem 1rem 2.5rem;
    gap: 1.25rem;
  }
  .article {
    max-width: 100%;
  }
  .hero {
    padding: 3rem 1rem 2rem;
    text-align: left;
  }
  .hero > *:not(.hero-bg) {
    position: relative;
    z-index: 1;
  }
  .hero::after {
    content: '';
    position: absolute;
    inset: 0.75rem 0.75rem 0;
    border-radius: 24px;
    background: linear-gradient(180deg, rgba(13, 20, 36, 0.95), rgba(10, 15, 27, 0.86));
    border: 1px solid rgba(42, 64, 112, 0.55);
  }
  .hero-bg {
    inset: 0;
  }
  .hero-week-badge {
    margin-bottom: 1rem;
  }
  .hero-title,
  .hero-subtitle,
  .hero-toc-preview {
    max-width: 100%;
    margin-left: 0;
    margin-right: 0;
  }
  .hero-subtitle {
    margin-bottom: 1.25rem;
    font-size: 0.98rem;
  }
  .hero-toc-preview {
    flex-wrap: nowrap;
    overflow-x: auto;
    padding-bottom: 0.2rem;
    justify-content: flex-start;
    scrollbar-width: none;
  }
  .hero-toc-preview::-webkit-scrollbar {
    display: none;
  }
  .toc-pill {
    flex: 0 0 auto;
  }
  .section {
    margin-bottom: 3rem;
  }
  .section-header {
    align-items: flex-start;
    gap: 0.75rem;
    margin-bottom: 1.4rem;
  }
  .section-number {
    margin-top: 0.2rem;
  }
  .viz-container[data-stable-layout='true'] {
    border-radius: 18px;
  }
  .viz-container[data-stable-layout='true'] .viz-mobile-stage {
    min-width: 520px;
  }
}

@media (max-width: 768px) {
  .hero {
    padding: 2.7rem 0.85rem 1.8rem;
  }
  .hero-subtitle {
    font-size: 0.95rem;
  }
  .section-title {
    font-size: 1.45rem;
  }
  .subsection-title {
    font-size: 1.08rem;
  }

  /* Stack grid layouts often used inline */
  [style*='grid-template-columns'] {
    grid-template-columns: 1fr !important;
  }
  .viz-container[data-stable-layout='true'] [style*='grid-template-columns'] {
    grid-template-columns: unset !important;
  }
}

@media (max-width: 640px) {
  html {
    font-size: 14px;
  }
  .nav {
    height: 58px;
  }
  .page-wrapper {
    padding-top: 58px;
  }
  .reading-progress {
    top: 58px;
  }
  .nav-brand {
    gap: 0.55rem;
  }
  .nav-brand-icon {
    width: 30px;
    height: 30px;
  }
  .nav-sidebar-toggle {
    padding: 0 0.72rem;
  }
  .nav-sidebar-toggle-label {
    font-size: 0.62rem;
  }
  .section-title {
    font-size: 1.34rem;
  }

  .viz-container {
    margin: 1.5rem 0;
  }
  .viz-body {
    padding: 0.9rem;
  }
  .viz-header,
  .viz-controls {
    padding-left: 0.9rem;
    padding-right: 0.9rem;
  }

  .callout {
    padding: 1rem;
    margin: 1rem 0;
  }
  .content-wrapper {
    padding: 1rem 0.75rem 2.2rem;
  }
  .hero::after {
    inset: 0.55rem 0.55rem 0;
    border-radius: 20px;
  }
  .sidebar {
    width: calc(100vw - 0.5rem);
    padding: 0.25rem 0.25rem 0.5rem;
  }
  .sidebar-week-links {
    grid-template-columns: 1fr;
  }
  .viz-container[data-stable-layout='true'] .viz-mobile-stage {
    min-width: 480px;
  }

  /* Interactive grids stacking */
  .gen-grid,
  .noise-grid,
  .oracle-grid,
  .complexity-grid {
    grid-template-columns: 1fr !important;
  }
  .viz-container[data-stable-layout='true'] .gen-grid,
  .viz-container[data-stable-layout='true'] .noise-grid,
  .viz-container[data-stable-layout='true'] .oracle-grid,
  .viz-container[data-stable-layout='true'] .complexity-grid {
    grid-template-columns: unset !important;
  }
}

/* === PEDAGOGICAL TOOLS === */

/* Details/Math Accordions */
.math-details {
  background: var(--bg-3);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  margin: 1.5rem 0;
  overflow: hidden;
}
.math-details summary {
  padding: 1rem 1.5rem;
  font-family: var(--font-mono);
  font-size: 0.85rem;
  color: var(--cyan);
  cursor: pointer;
  list-style: none;
  display: flex;
  align-items: center;
  gap: 0.75rem;
  user-select: none;
  background: var(--surface);
  border-bottom: 1px solid transparent;
  transition: var(--transition);
}
.math-details summary::-webkit-details-marker {
  display: none;
}
.math-details summary::before {
  content: '▶';
  font-size: 0.75rem;
  transition: transform 0.2s;
  color: var(--text-faint);
}
.math-details[open] summary {
  border-bottom: 1px solid var(--border);
  background: var(--bg-2);
}
.math-details[open] summary::before {
  transform: rotate(90deg);
}
.math-details-content {
  padding: 1.5rem;
}

/* Tooltips */
.has-tooltip {
  position: relative;
  cursor: help;
  border-bottom: 1px dotted var(--text-dim);
  transition: border-color var(--transition);
}
.has-tooltip:hover {
  border-bottom-color: var(--cyan);
}
.ui-tooltip {
  position: absolute;
  background: var(--surface-2);
  color: var(--text);
  padding: 0.75rem 1rem;
  border-radius: var(--radius);
  border: 1px solid var(--border-2);
  font-family: var(--font-body);
  font-size: 0.85rem;
  line-height: 1.5;
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.5);
  z-index: 10000;
  max-width: 300px;
  pointer-events: none;
  opacity: 0;
  transform: translateY(10px);
  transition:
    opacity 0.2s,
    transform 0.2s;
}
.ui-tooltip.visible {
  opacity: 1;
  transform: translateY(0);
}

/* Micro-Quizzes */
.micro-quiz {
  background: var(--bg-2);
  border: 1px solid var(--border);
  border-left: 3px solid var(--purple);
  border-radius: var(--radius);
  margin: 2rem 0;
  overflow: hidden;
}
.mq-header {
  background: var(--surface);
  padding: 1rem 1.5rem;
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--purple);
  display: flex;
  align-items: center;
  gap: 0.5rem;
  border-bottom: 1px solid var(--border);
}
.mq-body {
  padding: 1.5rem;
}
.mq-question {
  font-weight: 500;
  margin-bottom: 1.25rem;
}
.mq-options {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}
.mq-option {
  padding: 0.75rem 1rem;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 6px;
  cursor: pointer;
  transition: var(--transition);
  display: flex;
  align-items: center;
  gap: 0.75rem;
}
.mq-option:hover {
  border-color: var(--purple-dim);
  background: var(--surface);
}
.mq-option.correct {
  border-color: var(--green);
  background: rgba(0, 230, 118, 0.1);
}
.mq-option.incorrect {
  border-color: var(--red);
  background: rgba(255, 79, 110, 0.1);
}
.mq-feedback {
  margin-top: 1.25rem;
  padding: 1rem;
  border-radius: 6px;
  background: var(--surface);
  font-size: 0.9rem;
  display: none;
}
.mq-feedback.visible {
  display: block;
  animation: fadeInUp 0.3s ease;
}

/* Derivation Container */
.derivation-container {
  margin: 2.5rem 0;
}
.derivation-container .subsubsection-title {
  margin-top: 2rem;
  margin-bottom: 0.75rem;
  color: var(--cyan);
}
.derivation-container p {
  margin-bottom: 1rem;
}


/* Scrollytelling (Legacy/Other) */
.scrolly-container {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 3rem;
  margin: 3rem 0;
  align-items: start;
}
@media (max-width: 900px) {
  .scrolly-container {
    grid-template-columns: 1fr;
  }
}
.scrolly-graphic {
  position: sticky;
  top: 100px;
  background: var(--bg-2);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 2rem;
  min-height: 200px;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
}
.scrolly-text {
  display: flex;
  flex-direction: column;
}
.scrolly-step {
  min-height: 50vh;
  padding: 2rem 0;
  opacity: 0.3;
  transition: opacity 0.3s;
}
@media (max-width: 900px) {
  .scrolly-step {
    min-height: auto;
    padding: 1.5rem 0;
  }
  .scrolly-graphic {
    position: relative;
    top: 0;
    margin-bottom: 2rem;
  }
}
.scrolly-step.active {
  opacity: 1;
}

/* Math Coloring Variables */
:root {
  --color-alice: #4facf7;
  --color-bob: #f7a04f;
  --color-eve: #4ff7a0;
}
.color-alice {
  color: var(--color-alice);
}
.color-bob {
  color: var(--color-bob);
}
.color-eve {
  color: var(--color-eve);
}