:root {
  color-scheme: dark;
  --bg: #0b0c10;
  --bg-soft: #11131a;
  --paper: #f7f8fa;
  --ink: #f5f6f8;
  --muted: #a6abb7;
  --faint: #6B7280;
  --line: rgba(255, 255, 255, 0.11);
  --hf: #FFD21E;
  --hf-orange: #FF9D00;
  --video: #4285F4;
  --three-d: #EA4335;
  --world: #34A853;
  --next: #FBBC04;
  --accent: var(--hf);
  --display: ui-rounded, "Arial Rounded MT Bold", "Trebuchet MS", system-ui, sans-serif;
  --sans: Inter, ui-sans-serif, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  --mono: ui-monospace, "SFMono-Regular", Menlo, Consolas, monospace;
  --ease: cubic-bezier(.2, .8, .2, 1);
  --pad-x: clamp(34px, 5vw, 92px);
}

* { box-sizing: border-box; }
html, body { width: 100%; height: 100%; margin: 0; }
body {
  overflow: hidden;
  background: var(--bg);
  color: var(--ink);
  font-family: var(--sans);
  -webkit-font-smoothing: antialiased;
}
body[data-accent="video"] { --accent: var(--video); }
body[data-accent="three-d"] { --accent: var(--three-d); }
body[data-accent="world"] { --accent: var(--world); }
body[data-accent="next"] { --accent: var(--next); }
button, a { font: inherit; }
a { color: inherit; }
button { color: inherit; }

#deck { position: fixed; inset: 0; isolation: isolate; overflow: hidden; }
#atmosphere {
  position: absolute;
  inset: 0;
  z-index: -3;
  background:
    radial-gradient(55% 75% at 91% 7%, color-mix(in srgb, var(--accent) 14%, transparent), transparent 70%),
    radial-gradient(40% 60% at 6% 100%, rgba(255, 210, 30, .08), transparent 72%),
    linear-gradient(135deg, #12131a 0%, var(--bg) 48%, #07080b 100%);
  transition: background 700ms var(--ease);
}
#atmosphere::before {
  content: "";
  position: absolute;
  inset: 0;
  opacity: .17;
  background-image:
    linear-gradient(rgba(255,255,255,.08) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255,255,255,.08) 1px, transparent 1px);
  background-size: clamp(58px, 6vw, 104px) clamp(58px, 6vw, 104px);
  mask-image: linear-gradient(90deg, transparent 0%, black 20%, black 78%, transparent 100%);
}

#brand-bar {
  position: absolute;
  z-index: 12;
  top: 0;
  left: 0;
  right: 0;
  height: 74px;
  padding: 18px var(--pad-x);
  display: flex;
  align-items: center;
  justify-content: space-between;
  pointer-events: none;
}
.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
  font: 750 12px/1 var(--mono);
  letter-spacing: .17em;
  text-transform: uppercase;
  color: var(--hf);
  pointer-events: auto;
}
.brand img { width: 34px; height: 32px; object-fit: contain; }
#chapter-label {
  font: 650 11px/1 var(--mono);
  color: var(--muted);
  letter-spacing: .16em;
  text-transform: uppercase;
}

#reality-rail {
  position: absolute;
  z-index: 11;
  top: 50%;
  right: 24px;
  width: 6px;
  height: min(45vh, 390px);
  transform: translateY(-50%);
  display: grid;
  grid-template-rows: repeat(3, 1fr);
  gap: 7px;
}
#reality-rail span {
  border-radius: 99px;
  background: rgba(255,255,255,.1);
  transform: scaleX(.5);
  transform-origin: right center;
  transition: background 400ms var(--ease), transform 400ms var(--ease), box-shadow 400ms var(--ease);
}
#reality-rail [data-rail="video"].active { background: var(--video); }
#reality-rail [data-rail="three-d"].active { background: var(--three-d); }
#reality-rail [data-rail="world"].active { background: var(--world); }
#reality-rail span.active { transform: scaleX(1); box-shadow: 0 0 26px color-mix(in srgb, var(--accent) 75%, transparent); }

.scene-stage {
  position: absolute;
  inset: 74px 0 62px;
  z-index: 2;
  display: grid;
  place-items: center;
  padding: 18px calc(var(--pad-x) + 14px) 20px var(--pad-x);
}
.pane {
  width: min(100%, 1540px);
  max-height: 100%;
  opacity: 0;
  transform: translateY(22px);
  transition: opacity 520ms var(--ease), transform 520ms var(--ease);
}
.pane.is-visible { opacity: 1; transform: none; }
.scene-heading { margin-bottom: clamp(20px, 3vh, 38px); }
.micro-label {
  display: block;
  margin-bottom: 12px;
  color: var(--scene-accent, var(--accent));
  font: 750 clamp(10px, .8vw, 13px)/1 var(--mono);
  letter-spacing: .2em;
  text-transform: uppercase;
}
.scene-title {
  max-width: 1100px;
  margin: 0;
  font: 760 clamp(32px, 4.1vw, 68px)/1.03 var(--display);
  letter-spacing: -.035em;
  text-wrap: balance;
}
.scene-lead {
  max-width: 78ch;
  margin: -8px 0 clamp(20px, 3vh, 38px);
  color: var(--muted);
  font-size: clamp(16px, 1.35vw, 22px);
  line-height: 1.5;
}
.takeaway {
  margin: clamp(18px, 3vh, 34px) 0 0;
  padding: 14px 0 0 18px;
  border-left: 4px solid var(--scene-accent, var(--accent));
  color: var(--ink);
  font-size: clamp(15px, 1.22vw, 20px);
  line-height: 1.45;
}

/* Opening */
.title-pane {
  min-height: min(68vh, 680px);
  display: grid;
  grid-template-columns: minmax(0, 1.35fr) minmax(260px, .65fr);
  gap: clamp(40px, 8vw, 120px);
  align-items: center;
}
.hero-copy { position: relative; z-index: 1; }
.hero-title {
  max-width: 1040px;
  margin: 0;
  font: 790 clamp(56px, 7.6vw, 124px)/.89 var(--display);
  letter-spacing: -.065em;
  text-wrap: balance;
}
.hero-title::after { content: ""; display: block; width: clamp(90px, 12vw, 190px); height: 8px; margin-top: 28px; border-radius: 10px; background: linear-gradient(90deg, var(--hf), var(--hf-orange)); }
.hero-subtitle { max-width: 670px; margin: 26px 0 0; color: var(--muted); font-size: clamp(18px, 1.6vw, 26px); line-height: 1.45; }
.hero-bracket {
  justify-self: end;
  color: var(--hf);
  font: 800 clamp(84px, 13vw, 210px)/1 var(--mono);
  letter-spacing: -.35em;
  transform: translateX(-.15em);
  text-shadow: 0 0 80px rgba(255,210,30,.28);
}
.hero-realities { display: flex; gap: clamp(18px, 3vw, 46px); margin-top: clamp(34px, 5vh, 64px); }
.hero-reality { position: relative; display: grid; gap: 7px; padding-top: 10px; min-width: 115px; border-top: 2px solid var(--item-accent); }
.hero-number { color: var(--item-accent); font: 700 11px/1 var(--mono); letter-spacing: .14em; }
.hero-label { font: 700 clamp(16px, 1.3vw, 21px)/1 var(--sans); }

/* Profile */
.profile-grid { display: grid; grid-template-columns: 1.05fr .95fr; gap: clamp(30px, 5vw, 72px); align-items: stretch; }
.terminal { overflow: hidden; border: 1px solid var(--line); border-radius: 18px; background: rgba(4,5,8,.88); box-shadow: 0 34px 90px -48px rgba(0,0,0,.9); }
.terminal-bar, .code-chrome { height: 48px; display: flex; align-items: center; gap: 8px; padding: 0 18px; border-bottom: 1px solid var(--line); background: rgba(255,255,255,.035); }
.terminal-bar span, .code-chrome span { width: 10px; height: 10px; border-radius: 50%; background: var(--faint); }
.terminal-bar span:first-child, .code-chrome span:first-child { background: var(--three-d); }
.terminal-bar span:nth-child(2), .code-chrome span:nth-child(2) { background: var(--next); }
.terminal-bar span:nth-child(3), .code-chrome span:nth-child(3) { background: var(--world); }
.terminal-bar b, .code-chrome b { margin-left: auto; color: var(--faint); font: 650 11px/1 var(--mono); letter-spacing: .1em; text-transform: uppercase; }
.terminal-body { margin: 0; padding: clamp(24px, 3vw, 44px); display: grid; grid-template-columns: minmax(100px, auto) 1fr; gap: 18px 22px; font: 600 clamp(14px, 1.15vw, 19px)/1.4 var(--mono); }
.terminal-body dt { color: var(--hf); }
.terminal-body dd { margin: 0; color: var(--ink); }
.conversation-notes { padding: 8px 0; }
.note-list { list-style: none; margin: 0; padding: 0; display: grid; gap: 0; border-top: 1px solid var(--line); }
.note-list li { display: grid; grid-template-columns: 54px 1fr; gap: 18px; align-items: start; padding: 22px 0; border-bottom: 1px solid var(--line); }
.note-index { color: var(--hf); font: 700 12px/1.4 var(--mono); }
.note-list p { margin: 0; color: var(--muted); font-size: clamp(15px, 1.28vw, 20px); line-height: 1.45; }

/* Section transitions */
.section-pane { position: relative; min-height: min(66vh, 640px); display: grid; grid-template-columns: minmax(210px, .35fr) 1fr; align-items: center; gap: clamp(34px, 7vw, 110px); }
.section-number { color: transparent; font: 800 clamp(140px, 24vw, 360px)/.8 var(--display); letter-spacing: -.08em; -webkit-text-stroke: 2px var(--scene-accent); opacity: .75; }
.section-copy { max-width: 900px; }
.section-title { margin: 0; font: 780 clamp(46px, 6vw, 92px)/.97 var(--display); letter-spacing: -.05em; text-wrap: balance; }
.section-thesis { max-width: 750px; margin: 28px 0 0; color: var(--muted); font-size: clamp(18px, 1.6vw, 26px); line-height: 1.45; }
.section-mark { position: absolute; right: 0; bottom: 0; color: var(--scene-accent); font: 800 clamp(20px, 2vw, 34px)/1 var(--mono); letter-spacing: .12em; }

/* Prompts */
.prompt-layout.with-visual { display: grid; grid-template-columns: minmax(0, 1fr) minmax(320px, .82fr); gap: clamp(20px, 3vw, 42px); align-items: stretch; }
.prompt-block { position: relative; margin: 0; padding: clamp(28px, 4vw, 58px) clamp(30px, 4vw, 64px); display: grid; grid-template-columns: auto 1fr; gap: 20px; border: 1px solid color-mix(in srgb, var(--scene-accent) 35%, var(--line)); border-radius: 24px 24px 72px 24px; background: linear-gradient(135deg, color-mix(in srgb, var(--scene-accent) 10%, transparent), rgba(255,255,255,.025)); }
.prompt-block p { margin: 0; font: 650 clamp(22px, 2.35vw, 38px)/1.34 var(--display); letter-spacing: -.018em; }
.prompt-caret { color: var(--scene-accent); font: 800 clamp(24px, 2.5vw, 42px)/1.2 var(--mono); }
.prompt-visual { min-width: 0; margin: 0; overflow: hidden; border: 1px solid color-mix(in srgb, var(--scene-accent) 38%, var(--line)); border-radius: 24px 24px 72px 24px; background: #050609; box-shadow: 0 30px 80px -48px #000; }
.prompt-visual img { display: block; width: 100%; height: 100%; min-height: 230px; object-fit: cover; }
.outcome-row { display: grid; grid-template-columns: repeat(3, 1fr); gap: 0; margin-top: clamp(24px, 3vh, 40px); border-top: 1px solid var(--line); border-bottom: 1px solid var(--line); }
.outcome-item { position: relative; display: grid; gap: 10px; padding: clamp(18px, 2vw, 28px); }
.outcome-item + .outcome-item { border-left: 1px solid var(--line); }
.outcome-item::before { content: ""; position: absolute; left: 0; top: -2px; width: 48%; height: 3px; background: var(--item-accent); }
.outcome-label { color: var(--item-accent); font: 700 11px/1 var(--mono); letter-spacing: .15em; text-transform: uppercase; }
.outcome-item strong { font-size: clamp(16px, 1.3vw, 21px); line-height: 1.35; }

@media (max-height: 820px) and (min-width: 701px) {
  .prompt-layout.with-visual { grid-template-columns: minmax(0, 1.15fr) minmax(280px, .7fr); gap: 20px; }
  .prompt-visual img { min-height: 210px; }
  .prompt-pane--visual .outcome-item { padding-top: 14px; padding-bottom: 14px; }
  .prompt-pane--visual .takeaway { margin-top: 10px; padding-top: 8px; font-size: clamp(13px, 1.05vw, 17px); }
}

/* Concepts */
.concept-flow { display: flex; align-items: stretch; gap: clamp(10px, 1.2vw, 20px); }
.concept-node { flex: 1; min-width: 0; padding: clamp(20px, 2.5vw, 36px) clamp(18px, 2vw, 30px); border-top: 3px solid var(--scene-accent); border-bottom: 1px solid var(--line); background: linear-gradient(180deg, color-mix(in srgb, var(--scene-accent) 8%, transparent), transparent); opacity: .18; transform: translateY(18px); transition: opacity 460ms var(--ease), transform 460ms var(--ease), background 460ms var(--ease); }
.concept-node.revealed { opacity: 1; transform: none; }
.concept-tag { color: var(--scene-accent); font: 700 10px/1 var(--mono); letter-spacing: .16em; text-transform: uppercase; }
.concept-node h2 { margin: 18px 0 12px; font: 750 clamp(20px, 1.8vw, 30px)/1.08 var(--display); }
.concept-node p { margin: 0; color: var(--muted); font-size: clamp(14px, 1.1vw, 18px); line-height: 1.45; }
.concept-connector { align-self: center; color: var(--scene-accent); font: 700 clamp(18px, 2vw, 34px)/1 var(--mono); }

/* Comparisons */
.comparison-list { display: grid; grid-template-columns: repeat(3, 1fr); border-top: 1px solid var(--line); border-bottom: 1px solid var(--line); }
.comparison-item { position: relative; min-width: 0; padding: clamp(24px, 3vw, 46px); }
.comparison-item + .comparison-item { border-left: 1px solid var(--line); }
.comparison-item::after { content: ""; position: absolute; left: 0; bottom: -1px; width: 44%; height: 4px; background: var(--scene-accent); transform-origin: left; animation: rule-in 700ms var(--ease) calc(var(--i) * 100ms) both; }
.comparison-index { color: var(--scene-accent); font: 700 11px/1 var(--mono); letter-spacing: .15em; }
.comparison-item h2 { margin: 26px 0 8px; font: 780 clamp(27px, 2.5vw, 42px)/1 var(--display); letter-spacing: -.03em; }
.comparison-label { min-height: 2.4em; margin: 0 0 24px; color: var(--scene-accent); font: 700 clamp(12px, 1vw, 15px)/1.35 var(--mono); text-transform: uppercase; letter-spacing: .06em; }
.comparison-body { min-height: 5.7em; margin: 0 0 28px; color: var(--muted); font-size: clamp(14px, 1.15vw, 18px); line-height: 1.5; }
.comparison-metric { display: inline-block; font: 700 clamp(13px, 1vw, 16px)/1 var(--mono); }
@keyframes rule-in { from { transform: scaleX(0); } to { transform: scaleX(1); } }

/* Code */
.code-layout { display: grid; grid-template-columns: minmax(0, 1.55fr) minmax(230px, .45fr); gap: clamp(26px, 4vw, 58px); align-items: stretch; }
.code-window { overflow: hidden; border: 1px solid var(--line); border-radius: 16px; background: #06070a; box-shadow: 0 36px 90px -50px #000; }
.code-block { margin: 0; padding: clamp(14px, 1.6vw, 22px) 0; overflow: auto; font: 600 clamp(10px, .88vw, 14px)/1.45 var(--mono); tab-size: 2; }
.code-line { display: grid; grid-template-columns: 48px 1fr; min-height: 1.45em; padding: 0 20px 0 0; transition: opacity 260ms ease, background 260ms ease, color 260ms ease; }
.code-line.active { color: #fff; background: color-mix(in srgb, var(--scene-accent) 14%, transparent); box-shadow: inset 3px 0 var(--scene-accent); }
.code-line.muted { color: #7b8192; opacity: .5; }
.line-number { padding-right: 14px; color: #4e5362; text-align: right; user-select: none; }
.line-text { white-space: pre; }
.code-annotation { align-self: center; padding: clamp(24px, 3vw, 42px); border-left: 1px solid var(--line); }
.code-step { display: block; margin: 22px 0; color: var(--scene-accent); font: 800 clamp(34px, 4vw, 64px)/1 var(--display); letter-spacing: -.04em; }
.code-caption { margin: 0; color: var(--muted); font-size: clamp(16px, 1.35vw, 22px); line-height: 1.5; }

/* Media */
.media-layout { display: grid; grid-template-columns: minmax(260px, .42fr) minmax(0, 1.58fr); gap: clamp(30px, 5vw, 74px); align-items: center; }
.media-copy .scene-lead { margin: 0 0 28px; }
.media-fallback { display: inline-flex; align-items: center; padding-bottom: 7px; border-bottom: 2px solid var(--scene-accent); color: var(--ink); font: 700 13px/1 var(--mono); text-decoration: none; }
.media-frame { position: relative; min-height: min(55vh, 560px); overflow: hidden; border: 1px solid color-mix(in srgb, var(--scene-accent) 34%, var(--line)); border-radius: 18px 18px 60px 18px; background-position: center; background-size: cover; box-shadow: 0 42px 110px -58px #000; }
.media-frame::after { content: "Embedded demo"; position: absolute; right: 18px; bottom: 16px; padding: 7px 10px; border-radius: 999px; background: rgba(7,8,11,.76); color: var(--muted); font: 650 10px/1 var(--mono); letter-spacing: .08em; text-transform: uppercase; pointer-events: none; }
.media-load { position: absolute; left: 28px; bottom: 28px; z-index: 2; padding: 14px 18px; border: 1px solid rgba(255,255,255,.25); border-radius: 999px; background: rgba(7,8,11,.82); backdrop-filter: blur(12px); cursor: pointer; font: 700 12px/1 var(--mono); transition: background 220ms ease, color 220ms ease, border-color 220ms ease; }
.media-load:hover { color: #111; background: var(--scene-accent); border-color: var(--scene-accent); }
.media-embed { position: absolute; inset: 0; width: 100%; height: 100%; border: 0; background: #000; }

/* Resources */
.resource-groups { display: grid; grid-template-columns: repeat(3, 1fr); border-top: 1px solid var(--line); border-bottom: 1px solid var(--line); }
.resource-group { position: relative; padding: clamp(24px, 3vw, 44px); }
.resource-group + .resource-group { border-left: 1px solid var(--line); }
.resource-group::before { content: ""; position: absolute; left: 0; top: -2px; width: 46%; height: 4px; background: var(--item-accent); }
.resource-group h2 { margin: 0 0 18px; color: var(--item-accent); font: 780 clamp(26px, 2.4vw, 40px)/1 var(--display); }
.resource-group > p { min-height: 5.2em; margin: 0; color: var(--muted); font-size: clamp(14px, 1.1vw, 18px); line-height: 1.48; }
.resource-links { list-style: none; margin: 26px 0 0; padding: 0; display: grid; gap: 13px; }
.resource-links a { color: var(--ink); font: 650 clamp(12px, 1vw, 15px)/1.3 var(--mono); text-decoration-color: color-mix(in srgb, var(--item-accent) 55%, transparent); text-underline-offset: 5px; }

/* Close */
.thanks-pane { min-height: min(64vh, 620px); display: grid; grid-template-columns: 1fr auto; gap: clamp(50px, 10vw, 160px); align-items: center; }
.thanks-title { max-width: 980px; margin: 0; font: 790 clamp(54px, 7vw, 112px)/.92 var(--display); letter-spacing: -.06em; text-wrap: balance; }
.thanks-subtitle { max-width: 700px; margin: 30px 0 0; color: var(--muted); font-size: clamp(18px, 1.6vw, 27px); line-height: 1.4; }
.thanks-identity { margin-top: clamp(34px, 6vh, 72px); display: grid; gap: 8px; padding-left: 20px; border-left: 4px solid var(--hf); }
.thanks-identity strong { font-size: clamp(18px, 1.5vw, 24px); }
.thanks-identity span { color: var(--muted); font: 600 clamp(12px, 1vw, 15px)/1.4 var(--mono); }
.thanks-logo { width: clamp(150px, 18vw, 300px); filter: drop-shadow(0 24px 70px rgba(255,210,30,.22)); }

/* HUD and controls */
#hud { position: absolute; z-index: 13; left: var(--pad-x); right: var(--pad-x); bottom: 0; height: 62px; display: grid; grid-template-columns: auto 1fr auto; gap: 28px; align-items: center; }
#source-button { padding: 7px 0; border: 0; background: transparent; cursor: pointer; color: var(--muted); font: 650 10px/1 var(--mono); letter-spacing: .13em; text-transform: uppercase; }
#source-button:disabled { opacity: .28; cursor: default; }
kbd { margin-left: 4px; padding: 3px 5px; border: 1px solid var(--line); border-radius: 4px; color: var(--faint); font: inherit; }
#progress { height: 3px; overflow: hidden; border-radius: 10px; background: rgba(255,255,255,.09); }
#progress-fill { display: block; width: 0; height: 100%; border-radius: inherit; background: linear-gradient(90deg, var(--hf), var(--accent)); box-shadow: 0 0 16px var(--accent); transition: width 420ms var(--ease); }
#counter { color: var(--faint); font: 650 10px/1 var(--mono); letter-spacing: .12em; }
.nav-zone { position: absolute; z-index: 1; top: 74px; bottom: 62px; width: 20%; border: 0; background: transparent; opacity: 0; cursor: default; }
#back-zone { left: 0; }
#next-zone { right: 0; }

/* Sources */
#source-panel { width: min(760px, calc(100vw - 36px)); max-height: min(76vh, 780px); padding: 0; border: 1px solid var(--line); border-radius: 22px; background: rgba(11,12,16,.97); color: var(--ink); box-shadow: 0 44px 120px rgba(0,0,0,.7); }
#source-panel::backdrop { background: rgba(0,0,0,.72); backdrop-filter: blur(10px); }
.source-shell { padding: clamp(24px, 4vw, 46px); }
.source-shell header { display: flex; align-items: flex-start; justify-content: space-between; gap: 30px; }
.source-shell h2 { margin: 0; font: 780 clamp(34px, 4vw, 58px)/1 var(--display); }
#source-close { width: 42px; height: 42px; border: 1px solid var(--line); border-radius: 50%; background: transparent; cursor: pointer; font-size: 26px; }
#source-list { margin: 34px 0 0; padding: 0; list-style: none; border-top: 1px solid var(--line); }
#source-list li { display: grid; grid-template-columns: 1fr auto; gap: 18px; padding: 18px 0; border-bottom: 1px solid var(--line); }
#source-list a { color: var(--ink); font-size: clamp(14px, 1.2vw, 18px); line-height: 1.35; text-decoration-color: var(--hf); text-underline-offset: 5px; }
#source-list span { color: var(--faint); font: 600 10px/1.4 var(--mono); }
.source-empty { color: var(--muted); }

/* Preloader */
#preloader { position: fixed; inset: 0; z-index: 100; display: grid; place-content: center; justify-items: center; gap: 16px; background: var(--bg); transition: opacity 500ms var(--ease), visibility 500ms var(--ease); }
#preloader img { width: 82px; animation: hug 1.8s ease-in-out infinite; }
#preloader > span:not(.preload-track) { color: var(--muted); font: 650 11px/1 var(--mono); letter-spacing: .12em; text-transform: uppercase; }
.preload-track { width: 220px; height: 3px; overflow: hidden; border-radius: 9px; background: rgba(255,255,255,.1); }
#preload-fill { display: block; width: 0; height: 100%; background: var(--hf); transition: width 280ms ease; }
#preloader.is-done { opacity: 0; visibility: hidden; }
@keyframes hug { 0%, 100% { transform: translateY(0) rotate(-2deg); } 50% { transform: translateY(-8px) rotate(2deg); } }

button:focus-visible, a:focus-visible { outline: 3px solid var(--hf); outline-offset: 4px; }

@media (max-width: 980px) {
  :root { --pad-x: 28px; }
  #brand-bar { height: 62px; padding-top: 12px; padding-bottom: 12px; }
  .scene-stage { inset: 62px 0 52px; padding-right: 40px; }
  #hud { height: 52px; gap: 16px; }
  #reality-rail { right: 12px; }
  .title-pane { grid-template-columns: 1fr; min-height: 0; }
  .hero-bracket { position: absolute; right: 40px; top: 80px; opacity: .12; }
  .profile-grid, .media-layout { grid-template-columns: 1fr; }
  .media-copy { display: none; }
  .media-frame { min-height: min(58vh, 480px); }
  .section-pane { grid-template-columns: 150px 1fr; }
  .section-number { font-size: clamp(120px, 24vw, 200px); }
  .concept-flow { display: grid; grid-template-columns: repeat(2, 1fr); }
  .concept-connector { display: none; }
  .code-layout { grid-template-columns: 1fr; }
  .code-annotation { display: grid; grid-template-columns: auto 1fr; gap: 20px; align-items: center; padding: 14px 0 0; border-left: 0; border-top: 1px solid var(--line); }
  .code-annotation .micro-label { display: none; }
  .code-step { margin: 0; font-size: 28px; }
  .comparison-body { min-height: 7em; }
}

@media (max-width: 700px) {
  #chapter-label, #source-button kbd { display: none; }
  .brand span { display: none; }
  .scene-title { font-size: clamp(28px, 7vw, 42px); }
  .scene-heading { margin-bottom: 18px; }
  .hero-title { font-size: clamp(48px, 13vw, 76px); }
  .hero-realities { gap: 10px; }
  .hero-reality { min-width: 0; flex: 1; }
  .profile-grid { gap: 18px; }
  .conversation-notes { display: none; }
  .section-pane { grid-template-columns: 1fr; gap: 16px; }
  .section-number { font-size: 110px; }
  .section-title { font-size: 42px; }
  .concept-flow { grid-template-columns: 1fr 1fr; gap: 8px; }
  .concept-node { padding: 14px; }
  .comparison-list, .resource-groups { grid-template-columns: 1fr; }
  .comparison-item, .resource-group { padding: 14px 18px; }
  .comparison-item + .comparison-item, .resource-group + .resource-group { border-left: 0; border-top: 1px solid var(--line); }
  .comparison-item h2 { margin: 10px 0 4px; font-size: 23px; }
  .comparison-label, .comparison-body, .resource-group > p { min-height: 0; margin-bottom: 8px; }
  .comparison-body { font-size: 13px; }
  .takeaway { display: none; }
  .prompt-block { padding: 20px; border-radius: 18px; }
  .prompt-block p { font-size: 19px; }
  .prompt-layout.with-visual { grid-template-columns: 1fr; }
  .prompt-visual img { min-height: 180px; }
  .outcome-row { margin-top: 14px; }
  .outcome-item { padding: 12px 10px; }
  .outcome-item strong { font-size: 12px; }
  .code-block { font-size: 9px; }
  .code-line { grid-template-columns: 34px 1fr; }
  .thanks-pane { grid-template-columns: 1fr; }
  .thanks-logo { display: none; }
  #source-list li { grid-template-columns: 1fr; }
}

@media (max-height: 620px) {
  #brand-bar { height: 54px; }
  .brand img { width: 28px; height: 27px; }
  .scene-stage { inset: 54px 0 46px; padding-top: 8px; padding-bottom: 8px; }
  #hud { height: 46px; }
  .scene-heading { margin-bottom: 14px; }
  .micro-label { margin-bottom: 7px; }
  .scene-title { font-size: clamp(27px, 4.4vw, 48px); }
  .scene-lead { margin-bottom: 14px; font-size: clamp(13px, 1.25vw, 17px); }
  .title-pane { min-height: 0; }
  .hero-title { font-size: clamp(50px, 8vw, 88px); }
  .hero-subtitle { margin-top: 14px; font-size: 16px; }
  .hero-realities { margin-top: 20px; }
  .section-pane { min-height: 0; }
  .section-number { font-size: clamp(110px, 20vw, 220px); }
  .section-title { font-size: clamp(38px, 5.7vw, 66px); }
  .section-thesis { margin-top: 14px; font-size: 16px; }
  .prompt-block { padding: 18px 24px; }
  .prompt-block p { font-size: clamp(17px, 2vw, 26px); }
  .outcome-row { margin-top: 14px; }
  .outcome-item { padding: 12px 16px; }
  .concept-node { padding: 14px 16px; }
  .concept-node h2 { margin: 9px 0 6px; font-size: 19px; }
  .concept-node p { font-size: 12px; }
  .comparison-item { padding: 16px 22px; }
  .comparison-item h2 { margin: 14px 0 5px; font-size: 25px; }
  .comparison-label { min-height: 0; margin-bottom: 10px; }
  .comparison-body { min-height: 0; margin-bottom: 12px; font-size: 12px; }
  .code-block { max-height: 53vh; font-size: 9px; line-height: 1.25; }
  .code-chrome { height: 32px; }
  .media-frame { min-height: 52vh; }
  .resource-group { padding: 15px 20px; }
  .resource-group h2 { margin-bottom: 8px; font-size: 24px; }
  .resource-group > p { min-height: 0; font-size: 12px; }
  .resource-links { margin-top: 12px; gap: 7px; }
  .thanks-title { font-size: clamp(50px, 7vw, 82px); }
  .thanks-subtitle { margin-top: 16px; font-size: 16px; }
  .thanks-identity { margin-top: 22px; }
}

/* Short landscape screens need a presentation layout, not a stacked phone page. */
@media (max-height: 440px) {
  :root { --pad-x: 28px; }
  #brand-bar { height: 42px; padding: 7px var(--pad-x); }
  .brand { gap: 7px; font-size: 9px; }
  .brand img { width: 25px; height: 24px; }
  #chapter-label { font-size: 9px; }
  .scene-stage { inset: 42px 0 34px; padding: 2px 40px 2px var(--pad-x); }
  #hud { height: 34px; gap: 14px; }
  #source-button, #counter { font-size: 8px; }
  #reality-rail { right: 12px; height: 42vh; }
  .pane { width: min(100%, 1120px); }
  .scene-heading { margin-bottom: 7px; }
  .micro-label { margin-bottom: 4px; font-size: 8px; }
  .scene-title { max-width: 780px; font-size: clamp(22px, 3.7vw, 31px); line-height: 1; }
  .scene-lead { max-width: none; margin: -2px 0 7px; font-size: 10px; line-height: 1.3; }
  .takeaway { display: none; }

  .title-pane { min-height: 0; grid-template-columns: 1.35fr .65fr; gap: 26px; }
  .hero-title { max-width: 620px; font-size: clamp(42px, 7vw, 62px); line-height: .88; }
  .hero-title::after { width: 92px; height: 5px; margin-top: 12px; }
  .hero-subtitle { max-width: 520px; margin-top: 10px; font-size: 12px; }
  .hero-bracket { position: static; justify-self: end; font-size: 90px; opacity: 1; }
  .hero-realities { max-width: 430px; margin-top: 12px; gap: 18px; }
  .hero-reality { min-width: 72px; gap: 3px; padding-top: 5px; }
  .hero-number { font-size: 8px; }
  .hero-label { font-size: 11px; }

  .profile-grid { grid-template-columns: 1.05fr .95fr; gap: 18px; }
  .terminal-bar, .code-chrome { height: 28px; padding: 0 11px; }
  .terminal-bar span, .code-chrome span { width: 7px; height: 7px; }
  .terminal-bar b, .code-chrome b { font-size: 8px; }
  .terminal-body { padding: 12px 16px; grid-template-columns: 88px 1fr; gap: 7px 10px; font-size: 9px; line-height: 1.25; }
  .conversation-notes { display: block; padding: 0; }
  .note-list li { grid-template-columns: 28px 1fr; gap: 7px; padding: 7px 0; }
  .note-index { font-size: 8px; }
  .note-list p { font-size: 9px; line-height: 1.25; }

  .section-pane { min-height: 0; grid-template-columns: 120px 1fr; gap: 24px; }
  .section-number { font-size: 112px; }
  .section-title { font-size: clamp(34px, 5.5vw, 48px); }
  .section-thesis { margin-top: 8px; font-size: 12px; line-height: 1.3; }
  .section-mark { font-size: 14px; }

  .prompt-block { padding: 10px 14px; gap: 10px; border-radius: 12px 12px 32px 12px; }
  .prompt-block p { font-size: 13px; line-height: 1.25; }
  .prompt-caret { font-size: 15px; }
  .prompt-layout.with-visual { grid-template-columns: minmax(0, 1fr) minmax(250px, .8fr); gap: 10px; }
  .prompt-visual { border-radius: 12px 12px 32px 12px; }
  .prompt-visual img { min-height: 0; aspect-ratio: 16 / 9; }
  .outcome-row { margin-top: 7px; }
  .outcome-item { gap: 4px; padding: 7px 10px; }
  .outcome-label { font-size: 7px; }
  .outcome-item strong { font-size: 9px; }

  .concept-flow { display: flex; gap: 6px; }
  .concept-node { padding: 8px 9px; }
  .concept-node h2 { margin: 5px 0 4px; font-size: 12px; }
  .concept-node p { font-size: 8px; line-height: 1.25; }
  .concept-tag { font-size: 7px; }
  .concept-connector { display: block; font-size: 11px; }

  .comparison-item { padding: 9px 13px; }
  .comparison-index { font-size: 7px; }
  .comparison-item h2 { margin: 7px 0 3px; font-size: 17px; }
  .comparison-label { min-height: 0; margin-bottom: 5px; font-size: 7px; }
  .comparison-body { min-height: 0; margin-bottom: 6px; font-size: 8px; line-height: 1.25; }
  .comparison-metric { font-size: 8px; }

  .code-layout { grid-template-columns: minmax(0, 1.55fr) minmax(180px, .45fr); gap: 14px; }
  .code-block { max-height: 205px; padding: 6px 0; font-size: 7.5px; line-height: 1.2; }
  .code-line { grid-template-columns: 28px 1fr; min-height: 1.2em; padding-right: 8px; }
  .line-number { padding-right: 7px; }
  .code-annotation { display: block; align-self: center; padding: 10px 0 10px 12px; border-top: 0; border-left: 1px solid var(--line); }
  .code-annotation .micro-label { display: block; }
  .code-step { margin: 8px 0; font-size: 22px; }
  .code-caption { font-size: 9px; line-height: 1.3; }

  .media-layout { grid-template-columns: minmax(150px, .38fr) minmax(0, 1.62fr); gap: 18px; }
  .media-copy { display: block; }
  .media-copy .scene-lead { margin-bottom: 10px; }
  .media-fallback { padding-bottom: 4px; font-size: 8px; }
  .media-frame { min-height: 215px; border-radius: 12px 12px 34px 12px; }
  .media-load { left: 14px; bottom: 14px; padding: 9px 11px; font-size: 8px; }
  .media-frame::after { right: 10px; bottom: 9px; font-size: 7px; }

  .resource-group { padding: 9px 13px; }
  .resource-group h2 { margin-bottom: 5px; font-size: 17px; }
  .resource-group > p { min-height: 0; font-size: 8px; line-height: 1.25; }
  .resource-links { margin-top: 7px; gap: 4px; }
  .resource-links a { font-size: 8px; }

  .thanks-pane { min-height: 0; grid-template-columns: 1fr auto; gap: 34px; }
  .thanks-title { max-width: 700px; font-size: clamp(40px, 6.5vw, 58px); }
  .thanks-subtitle { margin-top: 9px; font-size: 12px; }
  .thanks-identity { margin-top: 13px; gap: 3px; padding-left: 10px; border-left-width: 3px; }
  .thanks-identity strong { font-size: 11px; }
  .thanks-identity span { font-size: 8px; }
  .thanks-logo { display: block; width: 110px; }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: .001ms !important;
    animation-iteration-count: 1 !important;
    scroll-behavior: auto !important;
    transition-duration: .001ms !important;
  }
  .concept-node { opacity: 1; transform: none; }
}