/* ============================================
   WORLD KNOWLEDGE — Design System
   ============================================ */

:root {
  /* Paper & Ink palette */
  --paper: #f4efe6;
  --paper-2: #ebe4d4;
  --paper-3: #e0d8c4;
  --ink: #1a1d2b;
  --ink-2: #2d3142;
  --ink-3: #5a5d6e;
  --ink-4: #8a8c9a;
  --rule: #c9c0aa;
  --rule-soft: #d9d2bf;

  /* Accents */
  --amber: #c8621a;
  --amber-soft: #e09a5a;
  --moss: #4a5d3a;
  --lapis: #2a4a6a;
  --wine: #6b2a3a;

  /* Subject hues */
  --s-math: #2a4a6a;
  --s-science: #4a5d3a;
  --s-history: #8b6b3a;
  --s-literature: #6b2a3a;
  --s-art: #c8621a;
  --s-geography: #3a6b5a;
  --s-music: #5a3a6b;
  --s-cs: #2d3142;

  /* Type */
  --serif: 'Instrument Serif', 'Playfair Display', Georgia, serif;
  --sans: 'Inter Tight', -apple-system, BlinkMacSystemFont, sans-serif;
  --mono: 'JetBrains Mono', 'SF Mono', Menlo, monospace;

  /* Space */
  --edge: 48px;
}

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

html, body {
  background: var(--paper);
  color: var(--ink);
  font-family: var(--sans);
  font-size: 15px;
  line-height: 1.5;
  -webkit-font-smoothing: antialiased;
  font-feature-settings: "ss01", "cv11";
}

body {
  min-height: 100vh;
  overflow-x: hidden;
}

::selection { background: var(--ink); color: var(--paper); }

/* Paper grain */
body::before {
  content: '';
  position: fixed;
  inset: 0;
  pointer-events: none;
  background-image:
    radial-gradient(circle at 20% 30%, rgba(26,29,43,0.015) 0%, transparent 50%),
    radial-gradient(circle at 80% 70%, rgba(200,98,26,0.02) 0%, transparent 50%);
  z-index: 1;
}

body::after {
  content: '';
  position: fixed;
  inset: 0;
  pointer-events: none;
  background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 200 200' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.9' numOctaves='3'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)' opacity='0.35'/%3E%3C/svg%3E");
  opacity: 0.08;
  mix-blend-mode: multiply;
  z-index: 2;
}

#root { position: relative; z-index: 3; }

/* Typography */
.serif { font-family: var(--serif); font-weight: 400; letter-spacing: -0.01em; }
.mono { font-family: var(--mono); font-size: 11px; letter-spacing: 0.04em; text-transform: uppercase; }
.sans { font-family: var(--sans); }

h1, h2, h3 { font-family: var(--serif); font-weight: 400; letter-spacing: -0.02em; line-height: 1.02; }

.eyebrow {
  font-family: var(--mono);
  font-size: 10px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--ink-3);
}

/* Rule / divider */
.rule { height: 1px; background: var(--rule); border: 0; }
.rule-thick { height: 2px; background: var(--ink); border: 0; }

/* Buttons */
button {
  font: inherit;
  border: none;
  background: none;
  cursor: pointer;
  color: inherit;
}

.btn-primary {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  padding: 10px 18px;
  background: var(--ink);
  color: var(--paper);
  border-radius: 999px;
  font-size: 13px;
  font-weight: 500;
  transition: all 0.2s;
}
.btn-primary:hover { background: var(--amber); transform: translateY(-1px); }

.btn-ghost {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 8px 14px;
  font-size: 13px;
  color: var(--ink-2);
  border-radius: 999px;
  transition: all 0.15s;
}
.btn-ghost:hover { background: var(--paper-3); color: var(--ink); }

/* Inputs */
input, textarea {
  font: inherit;
  color: inherit;
  background: transparent;
  border: none;
  outline: none;
}

/* Scrollbar */
::-webkit-scrollbar { width: 8px; height: 8px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: var(--rule); border-radius: 4px; }
::-webkit-scrollbar-thumb:hover { background: var(--ink-4); }

/* ============================================
   LAYOUT
   ============================================ */

.app {
  display: grid;
  grid-template-rows: auto 1fr;
  min-height: 100vh;
}

/* Header */
.topbar {
  display: grid;
  grid-template-columns: auto 1fr auto;
  align-items: center;
  gap: 32px;
  padding: 20px var(--edge);
  border-bottom: 1px solid var(--rule);
  background: var(--paper);
  position: sticky;
  top: 0;
  z-index: 20;
  backdrop-filter: blur(6px);
  background: rgba(244, 239, 230, 0.92);
}

.brand {
  display: flex;
  align-items: center;
  gap: 12px;
  cursor: pointer;
}
.brand-mark {
  width: 34px; height: 34px;
  display: block;
  flex-shrink: 0;
}
.brand-name { font-family: var(--serif); font-size: 20px; letter-spacing: -0.01em; }
.brand-sub { font-family: var(--mono); font-size: 9px; letter-spacing: 0.2em; color: var(--ink-3); text-transform: uppercase; }

.nav-crumb {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 13px;
  color: var(--ink-3);
}
.nav-crumb a { color: var(--ink-3); cursor: pointer; }
.nav-crumb a:hover { color: var(--ink); }
.nav-crumb .current { color: var(--ink); font-weight: 500; }
.nav-crumb .sep { color: var(--ink-4); }

.topbar-actions {
  display: flex;
  align-items: center;
  gap: 8px;
}

.search {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 8px 14px;
  background: var(--paper-2);
  border-radius: 999px;
  border: 1px solid transparent;
  transition: border-color 0.15s;
  min-width: 280px;
}
.search:focus-within { border-color: var(--ink-3); }
.search input { flex: 1; font-size: 13px; }
.search input::placeholder { color: var(--ink-4); }
.search kbd {
  font-family: var(--mono);
  font-size: 10px;
  padding: 2px 6px;
  background: var(--paper);
  border: 1px solid var(--rule);
  border-radius: 4px;
  color: var(--ink-3);
}

/* Main */
.main {
  position: relative;
}

/* ============================================
   PAGE: HOME / ATLAS
   ============================================ */

.atlas {
  padding: var(--edge);
  max-width: 1600px;
  margin: 0 auto;
}

.atlas-hero {
  display: grid;
  grid-template-columns: 1.3fr 1fr;
  gap: 80px;
  align-items: end;
  padding: 40px 0 60px;
  border-bottom: 1px solid var(--rule);
}

.atlas-hero h1 {
  font-size: clamp(56px, 8vw, 112px);
  line-height: 0.92;
  letter-spacing: -0.035em;
}
.atlas-hero h1 em {
  font-style: italic;
  color: var(--amber);
}

.atlas-hero-meta {
  padding-bottom: 12px;
  color: var(--ink-3);
  font-size: 14px;
  line-height: 1.6;
  max-width: 380px;
}
.atlas-hero-meta p + p { margin-top: 16px; }

.atlas-stats {
  display: flex;
  gap: 28px;
  margin-top: 20px;
  padding-top: 20px;
  border-top: 1px solid var(--rule);
}
.atlas-stats .stat-num {
  font-family: var(--serif);
  font-size: 34px;
  line-height: 1;
  color: var(--ink);
}
.atlas-stats .stat-lbl {
  font-family: var(--mono);
  font-size: 9px;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  color: var(--ink-3);
  margin-top: 6px;
}

/* Section header */
.section-header {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 24px;
  margin: 64px 0 32px;
}
.section-header h2 {
  font-size: 36px;
}
.section-header .eyebrow { margin-bottom: 10px; }
.section-header-right { display: flex; gap: 8px; }

/* Subject grid */
.subject-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 1px;
  background: var(--rule);
  border: 1px solid var(--rule);
}

.subject-card {
  position: relative;
  background: var(--paper);
  padding: 28px 28px 24px;
  cursor: pointer;
  transition: background 0.25s;
  min-height: 260px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  overflow: hidden;
}
.subject-card:hover { background: var(--paper-2); }
.subject-card:hover .sc-viz { transform: scale(1.04); }

.sc-head {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 12px;
}
.sc-num {
  font-family: var(--mono);
  font-size: 10px;
  color: var(--ink-3);
  letter-spacing: 0.15em;
}
.sc-count {
  font-family: var(--mono);
  font-size: 10px;
  color: var(--ink-3);
  letter-spacing: 0.1em;
}

.sc-viz {
  flex: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 16px 0;
  transition: transform 0.4s cubic-bezier(.2,.8,.2,1);
}
.sc-viz svg { width: 100%; height: 100px; }

.sc-name {
  font-family: var(--serif);
  font-size: 30px;
  line-height: 1;
  letter-spacing: -0.02em;
}
.sc-tag {
  font-family: var(--mono);
  font-size: 10px;
  letter-spacing: 0.1em;
  color: var(--ink-3);
  margin-top: 8px;
  text-transform: uppercase;
}

.sc-accent {
  position: absolute;
  top: 0; left: 0;
  width: 3px;
  height: 0;
  background: var(--accent);
  transition: height 0.3s;
}
.subject-card:hover .sc-accent { height: 100%; }

/* Featured strip */
.featured {
  margin-top: 80px;
  padding: 48px;
  background: var(--ink);
  color: var(--paper);
  display: grid;
  grid-template-columns: 1fr 1.2fr;
  gap: 60px;
  align-items: center;
  position: relative;
  overflow: hidden;
}
.featured::before {
  content: '';
  position: absolute;
  right: -120px; top: -120px;
  width: 400px; height: 400px;
  border-radius: 50%;
  background: radial-gradient(circle at 30% 30%, var(--amber) 0%, transparent 60%);
  opacity: 0.4;
}
.featured-body { position: relative; z-index: 1; }
.featured .eyebrow { color: var(--amber-soft); }
.featured h2 {
  font-size: 48px;
  margin: 14px 0 16px;
  line-height: 1;
}
.featured p {
  color: rgba(244,239,230,0.75);
  font-size: 15px;
  line-height: 1.6;
  max-width: 440px;
  margin-bottom: 24px;
}
.featured-visual {
  position: relative;
  z-index: 1;
  height: 280px;
  background: rgba(244,239,230,0.04);
  border: 1px solid rgba(244,239,230,0.12);
  display: flex;
  align-items: center;
  justify-content: center;
}

/* Pathways */
.pathways {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
  margin-top: 32px;
}
.pathway {
  padding: 24px;
  background: var(--paper-2);
  border: 1px solid var(--rule);
  cursor: pointer;
  transition: all 0.2s;
}
.pathway:hover { background: var(--paper); border-color: var(--ink-3); }
.pathway-num {
  font-family: var(--serif);
  font-size: 44px;
  color: var(--amber);
  line-height: 1;
}
.pathway h3 { font-size: 22px; margin: 12px 0 8px; }
.pathway-desc { font-size: 13px; color: var(--ink-3); line-height: 1.55; }
.pathway-meta {
  display: flex;
  gap: 12px;
  margin-top: 16px;
  padding-top: 16px;
  border-top: 1px solid var(--rule);
  font-family: var(--mono);
  font-size: 10px;
  color: var(--ink-3);
  letter-spacing: 0.1em;
  text-transform: uppercase;
}

/* Footer */
.footer {
  margin-top: 100px;
  padding: 40px var(--edge);
  border-top: 1px solid var(--rule);
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 24px;
  align-items: center;
  font-size: 12px;
  color: var(--ink-3);
}

/* ============================================
   PAGE: SUBJECT
   ============================================ */

.subject-page {
  max-width: 1600px;
  margin: 0 auto;
  padding: var(--edge);
}

.subject-hero {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 60px;
  padding: 32px 0 56px;
  border-bottom: 1px solid var(--rule);
  align-items: end;
}
.subject-hero h1 {
  font-size: clamp(64px, 9vw, 128px);
  line-height: 0.9;
  letter-spacing: -0.04em;
}
.subject-hero-num {
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 0.2em;
  color: var(--ink-3);
  margin-bottom: 16px;
}
.subject-hero-desc {
  font-size: 16px;
  line-height: 1.6;
  color: var(--ink-2);
  max-width: 460px;
  padding-bottom: 12px;
}
.subject-hero-desc p + p { margin-top: 14px; }

.subject-nav {
  display: flex;
  gap: 2px;
  margin: 32px 0;
  padding: 4px;
  background: var(--paper-2);
  border-radius: 999px;
  width: fit-content;
}
.subject-nav-item {
  padding: 8px 16px;
  border-radius: 999px;
  font-size: 13px;
  color: var(--ink-3);
  cursor: pointer;
  transition: all 0.15s;
}
.subject-nav-item:hover { color: var(--ink); }
.subject-nav-item.active { background: var(--ink); color: var(--paper); }

/* Topic tree */
.topic-map {
  display: grid;
  grid-template-columns: 280px 1fr;
  gap: 48px;
  margin-top: 40px;
}

.topic-outline {
  position: sticky;
  top: 100px;
  align-self: start;
}
.topic-outline-title {
  font-family: var(--mono);
  font-size: 10px;
  letter-spacing: 0.2em;
  color: var(--ink-3);
  text-transform: uppercase;
  margin-bottom: 16px;
  padding-bottom: 12px;
  border-bottom: 1px solid var(--rule);
}
.topic-outline-group {
  margin-bottom: 24px;
}
.topic-outline-group-name {
  font-family: var(--serif);
  font-size: 18px;
  margin-bottom: 8px;
}
.topic-outline-item {
  display: block;
  font-size: 13px;
  color: var(--ink-3);
  padding: 4px 0;
  cursor: pointer;
  transition: color 0.15s;
}
.topic-outline-item:hover { color: var(--ink); }
.topic-outline-item.visited::before {
  content: '✓ ';
  color: var(--moss);
}

.topic-content {
  min-height: 800px;
}

.topic-group-section {
  margin-bottom: 64px;
}
.topic-group-section:last-child { margin-bottom: 0; }

.topic-group-header {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  padding-bottom: 16px;
  border-bottom: 1px solid var(--rule);
  margin-bottom: 24px;
}
.topic-group-header h2 { font-size: 32px; }

.topic-list {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1px;
  background: var(--rule-soft);
  border: 1px solid var(--rule-soft);
}

.topic-card {
  background: var(--paper);
  padding: 24px 24px 20px;
  cursor: pointer;
  transition: background 0.2s;
  display: flex;
  flex-direction: column;
  gap: 12px;
  min-height: 160px;
}
.topic-card:hover { background: var(--paper-2); }

.topic-card-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 8px;
}
.topic-card-num {
  font-family: var(--mono);
  font-size: 10px;
  color: var(--ink-3);
  letter-spacing: 0.15em;
}
.topic-card-level {
  font-family: var(--mono);
  font-size: 9px;
  padding: 3px 7px;
  border: 1px solid var(--rule);
  border-radius: 3px;
  color: var(--ink-3);
  letter-spacing: 0.1em;
  text-transform: uppercase;
}
.topic-card h3 {
  font-size: 22px;
  line-height: 1.1;
}
.topic-card-desc {
  font-size: 13px;
  color: var(--ink-3);
  line-height: 1.5;
  flex: 1;
}
.topic-card-foot {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-top: 12px;
  border-top: 1px solid var(--rule-soft);
  font-family: var(--mono);
  font-size: 10px;
  color: var(--ink-3);
  letter-spacing: 0.1em;
  text-transform: uppercase;
}

/* ============================================
   PAGE: LESSON
   ============================================ */

.lesson {
  max-width: 900px;
  margin: 0 auto;
  padding: var(--edge);
}

.lesson-meta {
  display: flex;
  gap: 24px;
  padding: 24px 0;
  font-family: var(--mono);
  font-size: 10px;
  color: var(--ink-3);
  letter-spacing: 0.15em;
  text-transform: uppercase;
  border-bottom: 1px solid var(--rule);
}

.lesson-header {
  padding: 40px 0 32px;
  border-bottom: 1px solid var(--rule);
}
.lesson-header h1 {
  font-size: 64px;
  line-height: 0.95;
  margin-bottom: 16px;
}
.lesson-header .dek {
  font-size: 18px;
  line-height: 1.55;
  color: var(--ink-2);
  max-width: 640px;
}

.lesson-progress {
  display: flex;
  gap: 4px;
  margin-top: 24px;
}
.lesson-progress-seg {
  flex: 1;
  height: 3px;
  background: var(--rule);
  transition: background 0.3s;
}
.lesson-progress-seg.done { background: var(--ink); }
.lesson-progress-seg.current { background: var(--amber); }

.lesson-body {
  padding: 40px 0;
  font-size: 17px;
  line-height: 1.7;
  color: var(--ink-2);
}
.lesson-body h2 {
  font-size: 32px;
  margin: 40px 0 16px;
  color: var(--ink);
}
.lesson-body h3 {
  font-size: 22px;
  margin: 32px 0 12px;
  color: var(--ink);
  font-family: var(--sans);
  font-weight: 600;
  letter-spacing: 0;
}
.lesson-body p { margin-bottom: 18px; }
.lesson-body p + p { margin-top: -4px; }
.lesson-body strong { color: var(--ink); font-weight: 600; }
.lesson-body .lead {
  font-family: var(--serif);
  font-size: 24px;
  line-height: 1.4;
  color: var(--ink);
  margin-bottom: 28px;
}
.lesson-body .lead::first-letter {
  font-size: 5em;
  float: left;
  line-height: 0.85;
  margin: 0.05em 0.1em 0 -0.02em;
  color: var(--amber);
}

.pull-quote {
  margin: 40px 0;
  padding: 20px 32px;
  border-left: 3px solid var(--amber);
  font-family: var(--serif);
  font-size: 26px;
  line-height: 1.3;
  color: var(--ink);
}
.pull-quote cite {
  display: block;
  font-family: var(--mono);
  font-size: 11px;
  font-style: normal;
  letter-spacing: 0.15em;
  color: var(--ink-3);
  margin-top: 12px;
  text-transform: uppercase;
}

/* Interactive embeds */
.interactive {
  margin: 40px 0;
  background: var(--paper-2);
  border: 1px solid var(--rule);
  overflow: hidden;
}
.interactive-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 14px 20px;
  border-bottom: 1px solid var(--rule);
  background: var(--paper);
}
.interactive-title {
  font-family: var(--mono);
  font-size: 10px;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--ink-3);
}
.interactive-dot {
  width: 6px; height: 6px;
  border-radius: 50%;
  background: var(--moss);
  animation: pulse 2s infinite;
  margin-right: 8px;
  display: inline-block;
}
@keyframes pulse {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.4; }
}
.interactive-body {
  padding: 32px;
  min-height: 320px;
}
.interactive-foot {
  padding: 14px 20px;
  border-top: 1px solid var(--rule);
  font-size: 12px;
  color: var(--ink-3);
  display: flex;
  justify-content: space-between;
  align-items: center;
}

/* Lesson footer nav */
.lesson-nav {
  margin-top: 60px;
  padding-top: 32px;
  border-top: 2px solid var(--ink);
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 24px;
}
.lesson-nav-item {
  padding: 20px;
  background: var(--paper-2);
  cursor: pointer;
  transition: background 0.2s;
}
.lesson-nav-item:hover { background: var(--paper-3); }
.lesson-nav-item.next { text-align: right; }
.lesson-nav-dir {
  font-family: var(--mono);
  font-size: 10px;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--ink-3);
  margin-bottom: 6px;
}
.lesson-nav-title {
  font-family: var(--serif);
  font-size: 22px;
  line-height: 1.2;
}

/* ============================================
   CLAUDE TUTOR DOCK
   ============================================ */

.tutor-fab {
  position: fixed;
  right: 24px;
  bottom: 24px;
  z-index: 40;
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 12px 18px 12px 14px;
  background: var(--ink);
  color: var(--paper);
  border-radius: 999px;
  cursor: pointer;
  box-shadow: 0 12px 32px rgba(26,29,43,0.25);
  transition: all 0.25s cubic-bezier(.2,.8,.2,1);
}
.tutor-fab:hover { transform: translateY(-2px); background: var(--amber); }

.tutor-fab-orb {
  width: 26px; height: 26px;
  border-radius: 50%;
  background: radial-gradient(circle at 30% 30%, var(--amber-soft), var(--amber) 60%, #8a3d0a);
  box-shadow: inset 0 0 0 1px rgba(255,255,255,0.15);
  position: relative;
  overflow: hidden;
}
.tutor-fab-orb::after {
  content: '';
  position: absolute;
  inset: 2px;
  border-radius: 50%;
  background: conic-gradient(from 0deg, transparent, rgba(255,255,255,0.25), transparent);
  animation: spin 4s linear infinite;
}
@keyframes spin { to { transform: rotate(360deg); } }

.tutor-fab-label { font-size: 13px; font-weight: 500; }
.tutor-fab-kbd {
  font-family: var(--mono);
  font-size: 9px;
  padding: 2px 6px;
  background: rgba(244,239,230,0.12);
  border-radius: 4px;
  letter-spacing: 0.1em;
}

/* Dock panel */
.tutor-dock {
  position: fixed;
  right: 24px;
  bottom: 24px;
  width: 420px;
  height: min(640px, 80vh);
  background: var(--paper);
  border: 1px solid var(--ink);
  box-shadow: 0 20px 60px rgba(26,29,43,0.3);
  display: flex;
  flex-direction: column;
  z-index: 50;
  animation: dockIn 0.3s cubic-bezier(.2,.8,.2,1);
}
@keyframes dockIn {
  from { opacity: 0; transform: translateY(16px); }
  to { opacity: 1; transform: translateY(0); }
}

.tutor-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 14px 16px;
  border-bottom: 1px solid var(--rule);
  background: var(--paper-2);
}
.tutor-head-left { display: flex; align-items: center; gap: 10px; }
.tutor-head-name {
  font-family: var(--serif);
  font-size: 18px;
}
.tutor-head-sub {
  font-family: var(--mono);
  font-size: 9px;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  color: var(--ink-3);
}
.tutor-close {
  width: 28px; height: 28px;
  display: grid; place-items: center;
  border-radius: 50%;
  color: var(--ink-3);
}
.tutor-close:hover { background: var(--paper-3); color: var(--ink); }

.tutor-tabs {
  display: flex;
  gap: 2px;
  padding: 8px;
  border-bottom: 1px solid var(--rule);
}
.tutor-tab {
  flex: 1;
  padding: 6px 10px;
  font-size: 11px;
  font-family: var(--mono);
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--ink-3);
  border-radius: 4px;
  text-align: center;
}
.tutor-tab:hover { background: var(--paper-2); color: var(--ink); }
.tutor-tab.active { background: var(--ink); color: var(--paper); }

.tutor-body {
  flex: 1;
  overflow-y: auto;
  padding: 16px;
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.tutor-msg {
  padding: 12px 14px;
  font-size: 14px;
  line-height: 1.55;
  border-radius: 2px;
  max-width: 86%;
  animation: fadeUp 0.25s ease-out;
}
@keyframes fadeUp {
  from { opacity: 0; transform: translateY(4px); }
  to { opacity: 1; transform: translateY(0); }
}
.tutor-msg.user {
  background: var(--ink);
  color: var(--paper);
  align-self: flex-end;
}
.tutor-msg.claude {
  background: var(--paper-2);
  color: var(--ink);
  align-self: flex-start;
  border-left: 3px solid var(--amber);
}
.tutor-msg.claude strong { color: var(--amber); }

.tutor-welcome {
  padding: 12px;
  font-family: var(--serif);
  font-size: 22px;
  line-height: 1.25;
  color: var(--ink);
}
.tutor-welcome span { color: var(--amber); font-style: italic; }

.tutor-suggest-title {
  font-family: var(--mono);
  font-size: 9px;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--ink-3);
  margin: 8px 4px 4px;
}
.tutor-suggest {
  display: flex;
  flex-direction: column;
  gap: 4px;
}
.tutor-suggest-item {
  padding: 10px 12px;
  background: var(--paper-2);
  border: 1px solid var(--rule);
  font-size: 13px;
  cursor: pointer;
  transition: all 0.15s;
  display: flex;
  align-items: center;
  gap: 10px;
  text-align: left;
}
.tutor-suggest-item:hover { background: var(--paper-3); border-color: var(--ink-3); }
.tutor-suggest-item .sym {
  font-family: var(--serif);
  font-size: 18px;
  color: var(--amber);
  width: 20px;
  text-align: center;
}

.tutor-input-row {
  padding: 12px;
  border-top: 1px solid var(--rule);
  display: flex;
  gap: 8px;
  align-items: flex-end;
  background: var(--paper-2);
}
.tutor-input {
  flex: 1;
  padding: 10px 12px;
  background: var(--paper);
  border: 1px solid var(--rule);
  border-radius: 4px;
  font-size: 14px;
  min-height: 40px;
  max-height: 120px;
  resize: none;
  line-height: 1.4;
  transition: border-color 0.15s;
}
.tutor-input:focus { border-color: var(--ink); }
.tutor-send {
  width: 40px; height: 40px;
  background: var(--ink);
  color: var(--paper);
  border-radius: 50%;
  display: grid;
  place-items: center;
  flex-shrink: 0;
  transition: all 0.15s;
}
.tutor-send:hover { background: var(--amber); }
.tutor-send:disabled { opacity: 0.3; cursor: not-allowed; }

.tutor-typing {
  display: flex;
  gap: 4px;
  padding: 12px;
}
.tutor-typing span {
  width: 6px; height: 6px;
  border-radius: 50%;
  background: var(--ink-3);
  animation: bounce 1.2s infinite;
}
.tutor-typing span:nth-child(2) { animation-delay: 0.15s; }
.tutor-typing span:nth-child(3) { animation-delay: 0.3s; }
@keyframes bounce {
  0%, 60%, 100% { transform: translateY(0); opacity: 0.3; }
  30% { transform: translateY(-6px); opacity: 1; }
}

/* Inline context chip */
.tutor-ctx {
  padding: 8px 12px;
  background: var(--paper-2);
  border: 1px dashed var(--rule);
  font-size: 12px;
  color: var(--ink-3);
  font-family: var(--mono);
  letter-spacing: 0.05em;
  display: flex;
  align-items: center;
  gap: 8px;
}
.tutor-ctx strong { color: var(--ink); font-weight: 500; font-family: var(--sans); letter-spacing: 0; }

/* Quiz */
.quiz-card {
  padding: 16px;
  background: var(--paper-2);
  border: 1px solid var(--rule);
  border-left: 3px solid var(--amber);
}
.quiz-q { font-size: 15px; font-weight: 500; margin-bottom: 12px; }
.quiz-opts { display: flex; flex-direction: column; gap: 6px; }
.quiz-opt {
  padding: 8px 12px;
  background: var(--paper);
  border: 1px solid var(--rule);
  font-size: 13px;
  text-align: left;
  cursor: pointer;
  transition: all 0.15s;
}
.quiz-opt:hover { background: var(--paper-3); }
.quiz-opt.correct { background: var(--moss); color: var(--paper); border-color: var(--moss); }
.quiz-opt.wrong { background: var(--wine); color: var(--paper); border-color: var(--wine); }

/* ============================================
   HIGHLIGHT + "ASK CLAUDE" TOOLTIP
   ============================================ */

.ask-tip {
  position: absolute;
  background: var(--ink);
  color: var(--paper);
  font-size: 12px;
  padding: 6px 12px;
  border-radius: 999px;
  display: flex;
  align-items: center;
  gap: 6px;
  cursor: pointer;
  box-shadow: 0 6px 20px rgba(0,0,0,0.2);
  z-index: 100;
  white-space: nowrap;
  animation: fadeUp 0.15s ease-out;
}
.ask-tip:hover { background: var(--amber); }
.ask-tip-dot {
  width: 10px; height: 10px;
  border-radius: 50%;
  background: radial-gradient(circle at 30% 30%, var(--amber-soft), var(--amber));
}

/* ============================================
   RESPONSIVE
   ============================================ */

@media (max-width: 1100px) {
  :root { --edge: 32px; }
  .subject-grid { grid-template-columns: repeat(2, 1fr); }
  .atlas-hero { grid-template-columns: 1fr; gap: 32px; }
  .topic-map { grid-template-columns: 1fr; }
  .topic-outline { position: static; }
  .topic-list { grid-template-columns: 1fr; }
  .featured { grid-template-columns: 1fr; }
  .pathways { grid-template-columns: 1fr; }
  .subject-hero { grid-template-columns: 1fr; }
  .search { min-width: 0; }
}

@media (max-width: 600px) {
  :root { --edge: 20px; }
  .topbar { grid-template-columns: auto 1fr; gap: 12px; }
  .search { display: none; }
  .tutor-dock { right: 12px; left: 12px; bottom: 12px; width: auto; }
}

/* ============================================
   COMMAND PALETTE
   ============================================ */
.palette-backdrop {
  position: fixed;
  inset: 0;
  background: rgba(26, 29, 43, 0.35);
  backdrop-filter: blur(4px);
  z-index: 100;
  display: flex;
  align-items: flex-start;
  justify-content: center;
  padding-top: 14vh;
  animation: fadeUp 0.2s ease-out;
}
.palette {
  width: min(640px, 92vw);
  background: var(--paper);
  border: 1px solid var(--ink);
  box-shadow: 0 30px 80px rgba(0,0,0,0.3);
  display: flex;
  flex-direction: column;
  max-height: 70vh;
}
.palette-input-row {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 16px 20px;
  border-bottom: 1px solid var(--rule);
}
.palette-input-row input {
  flex: 1;
  font-family: var(--serif);
  font-size: 22px;
}
.palette-input-row input::placeholder { color: var(--ink-4); }
.palette-input-row kbd {
  font-family: var(--mono);
  font-size: 10px;
  padding: 3px 7px;
  background: var(--paper-2);
  border: 1px solid var(--rule);
  border-radius: 4px;
  color: var(--ink-3);
}
.palette-results {
  flex: 1;
  overflow-y: auto;
  padding: 6px;
}
.palette-item {
  display: flex;
  align-items: center;
  gap: 14px;
  width: 100%;
  padding: 12px 14px;
  text-align: left;
  border-radius: 2px;
  transition: background 0.1s;
}
.palette-item.active, .palette-item:hover { background: var(--paper-2); }
.palette-item-icon {
  width: 30px; height: 30px;
  display: grid; place-items: center;
  background: var(--paper);
  border: 1px solid var(--rule);
  color: var(--ink-3);
  flex-shrink: 0;
}
.palette-item.active .palette-item-icon { color: var(--amber); border-color: var(--amber); }
.palette-item-body { flex: 1; min-width: 0; }
.palette-item-name { font-size: 14px; font-weight: 500; }
.palette-item-desc { font-size: 12px; color: var(--ink-3); white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.palette-item-tag {
  font-size: 9px;
  letter-spacing: 0.15em;
  color: var(--ink-3);
  padding: 3px 8px;
  border: 1px solid var(--rule);
  border-radius: 3px;
}
.palette-empty { padding: 40px; text-align: center; color: var(--ink-3); }
.palette-foot {
  padding: 10px 20px;
  border-top: 1px solid var(--rule);
  display: flex;
  gap: 20px;
  color: var(--ink-3);
  background: var(--paper-2);
}

/* Flashcards */
.flashcard-stage {
  margin: 24px 0;
  perspective: 1400px;
  cursor: pointer;
}
.flashcard {
  position: relative;
  width: 100%;
  height: 360px;
  transform-style: preserve-3d;
  transition: transform 0.6s cubic-bezier(.2,.8,.2,1);
}
.flashcard.flipped { transform: rotateY(180deg); }
.flashcard-face {
  position: absolute;
  inset: 0;
  backface-visibility: hidden;
  background: var(--paper);
  border: 1px solid var(--ink);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: space-between;
  padding: 40px;
}
.flashcard-back {
  transform: rotateY(180deg);
  background: var(--paper-2);
  border-left: 4px solid var(--amber);
}
.flashcard-rate {
  padding: 18px;
  background: var(--paper);
  border: 1px solid var(--rule);
  border-top: 3px solid;
  text-align: center;
  transition: all 0.15s;
}
.flashcard-rate:hover { background: var(--paper-2); transform: translateY(-2px); }


/* ============================================
   Lesson Resources
   ============================================ */
.lesson-resources {
  margin-top: 64px;
  padding-top: 48px;
  border-top: 1px solid var(--rule);
}
.lesson-resources .res-header { margin-bottom: 32px; }
.lesson-resources .res-title { font-size: 32px; margin: 8px 0 12px; }
.lesson-resources .res-dek { color: var(--ink-3); font-size: 15px; max-width: 60ch; }
.res-group { margin-bottom: 28px; }
.res-group-head {
  display: flex; align-items: baseline; gap: 10px;
  padding-bottom: 10px;
  border-bottom: 1px solid var(--rule);
  margin-bottom: 4px;
}
.res-group-icon {
  width: 22px; height: 22px; display: inline-grid; place-items: center;
  background: var(--ink); color: var(--paper);
  font-size: 11px; border-radius: 2px;
}
.res-group-title {
  font-family: var(--serif); font-size: 20px; font-style: italic;
  color: var(--ink);
}
.res-group-count {
  margin-left: auto;
  font-family: var(--mono); font-size: 11px;
  color: var(--ink-3);
}
.res-list { list-style: none; padding: 0; margin: 0; }
.res-item {
  display: flex; align-items: center; gap: 12px;
  padding: 14px 4px;
  border-bottom: 1px dashed var(--rule);
}
.res-item:last-child { border-bottom: none; }
.res-link {
  flex: 1; min-width: 0;
  text-decoration: none; color: inherit;
  display: block;
}
.res-item-title {
  font-size: 15px; font-weight: 500; color: var(--ink);
  line-height: 1.3; margin-bottom: 3px;
  transition: color 0.15s;
}
.res-link:hover .res-item-title { color: var(--accent, var(--ink-2)); }
.res-item-meta {
  font-size: 12px; color: var(--ink-3);
  font-family: var(--mono);
}
.res-arrow {
  flex: 0 0 auto;
  width: 32px; height: 32px;
  display: grid; place-items: center;
  text-decoration: none; color: var(--ink-3);
  font-size: 14px;
  transition: all 0.15s;
  border: 1px solid transparent;
  border-radius: 2px;
}
.res-arrow:hover {
  color: var(--ink); border-color: var(--rule);
  background: var(--paper-2);
}