:root {
  --bg: #F2EDE6;
  --text-primary: #3A3632;
  --text-secondary: #8A8279;
  --accent-sage: #6B7B6E;
  --accent-clay: #C4A882;
  --divider: #B8AFA6;
  --highlight: #8B9E82;
  --ink: #2A2520;
  --grid-gap: clamp(16px, 3vw, 48px);
  --section-height: 100vh;
}

/* implementation terms: Intersection Observer thresholds calculated per-square. square zooms in IntersectionObserver` with multiple thresholds (0 */

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--text-primary);
  font-family: "Libre Baskerville", Georgia, serif;
  font-size: clamp(1rem, 1.8vw, 1.25rem);
  line-height: 1.65;
  letter-spacing: 0.01em;
}

.manual { overflow: hidden; }

.panel {
  position: relative;
  min-height: var(--section-height);
  width: 100%;
  display: grid;
  align-items: center;
  padding: clamp(48px, 8vh, 96px) 0;
}

.panel-grid {
  display: grid;
  grid-template-columns: repeat(12, 1fr);
  gap: var(--grid-gap);
  width: min(100% - clamp(32px, 8vw, 112px), 1440px);
  margin: 0 auto;
}

.section-rule {
  width: min(100% - clamp(32px, 8vw, 112px), 1440px);
  height: 1px;
  margin: 0 auto;
  position: relative;
  background: linear-gradient(90deg, transparent 0 8.333%, var(--divider) 8.333% 91.667%, transparent 91.667% 100%);
}

.section-rule span {
  position: absolute;
  width: 6px;
  height: 6px;
  left: 50%;
  top: 50%;
  transform: translate(-50%, -50%);
  background: var(--divider);
}

svg { display: block; overflow: visible; }
line { stroke: var(--divider); stroke-width: 1; stroke-dasharray: 4 8; }

.premise-diagram { grid-column: 6 / 12; position: relative; align-self: end; }
.fragment-square { width: min(60vw, 680px); margin-left: auto; }
.fragment polygon, .resolve-fragment polygon { fill: var(--accent-sage); }
.fragment-tr polygon, .resolve-tr polygon, .fragment-bl polygon, .resolve-bl polygon { fill: var(--accent-clay); }
.fragment { transform-box: fill-box; transform-origin: center; transition: transform 0.8s cubic-bezier(0.22, 1, 0.36, 1); will-change: transform; }
body.is-drifting .fragment-tl { transform: translate(-40px, -30px) rotate(-8deg); }
body.is-drifting .fragment-tr { transform: translate(35px, -25px) rotate(6deg); }
body.is-drifting .fragment-bl { transform: translate(-30px, 40px) rotate(-5deg); }
body.is-drifting .fragment-br { transform: translate(45px, 35px) rotate(10deg); }

.intro-copy {
  grid-column: 2 / 8;
  margin: clamp(24px, 5vh, 64px) 0 0;
  font-style: italic;
  max-width: 760px;
}

.body-copy { grid-column: 3 / 11; max-width: 880px; margin: 0; }
.callout, figcaption, .step span {
  font-family: "DM Mono", ui-monospace, monospace;
  font-size: clamp(0.65rem, 1vw, 0.75rem);
  line-height: 1.5;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--text-secondary);
}

.callout { position: absolute; }
.callout-a { left: 8%; top: 14%; }
.callout-b { right: 1%; bottom: 18%; }

.anatomy-set {
  grid-column: 2 / 12;
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: clamp(40px, 8vw, 128px);
  margin-bottom: clamp(44px, 9vh, 88px);
}

.part { margin: 0; text-align: center; }
.part svg { width: min(100%, 220px); margin: 0 auto 22px; }
.part-circle circle { fill: var(--text-secondary); }
.part-triangle polygon { fill: var(--accent-clay); }
.part-rectangle rect { fill: var(--accent-sage); }

.grid-paper::before {
  content: "";
  position: absolute;
  inset: 0;
  opacity: 0.4;
  background-image: linear-gradient(var(--divider) 0.5px, transparent 0.5px), linear-gradient(90deg, var(--divider) 0.5px, transparent 0.5px);
  background-size: 24px 24px;
  pointer-events: none;
}

.timeline { grid-column: 3 / 11; position: relative; display: grid; gap: clamp(20px, 3vh, 36px); }
.step { display: grid; grid-template-columns: minmax(86px, 0.18fr) 1fr; align-items: center; gap: clamp(16px, 3vw, 42px); }
.step::after { content: ""; grid-column: 2; height: 16px; width: var(--w); background: var(--accent-clay); order: 3; }
.step b {
  grid-row: span 2;
  font-family: "Libre Baskerville", Georgia, serif;
  font-size: clamp(3rem, 6vw, 5rem);
  line-height: 1;
  color: var(--accent-sage);
}
.step span { max-width: 540px; }

.focus-grid-wrap { position: relative; place-items: center; }
.focus-grid { grid-column: 4 / 10; width: min(68vw, 560px); }
.focus-cell { transform-box: fill-box; transform-origin: center; transition: transform 0.6s cubic-bezier(0.25, 0.46, 0.45, 0.94); will-change: transform; }
.focus-cell rect { fill: var(--accent-clay); }
.focus-cell.is-active { transform: scale(3); }
.focus-cell.is-active rect { fill: var(--accent-sage); }
.focus-label { grid-column: 9 / 12; top: 20%; right: 9%; }

.resolve { color: var(--ink); }
.resolve-stack { display: grid; justify-items: center; gap: clamp(28px, 5vh, 56px); }
.resolved-square { width: min(55vw, 430px); }
.resolve-fragment { transform-box: fill-box; transform-origin: center; transition: transform 0.8s cubic-bezier(0.22, 1, 0.36, 1); will-change: transform; }
.resolve-tl { transform: translate(-70px, -54px) rotate(-8deg); transition-delay: 240ms; }
.resolve-tr { transform: translate(60px, -48px) rotate(6deg); transition-delay: 160ms; }
.resolve-bl { transform: translate(-58px, 62px) rotate(-5deg); transition-delay: 80ms; }
.resolve-br { transform: translate(72px, 58px) rotate(10deg); transition-delay: 0ms; }
.resolve.is-assembled .resolve-fragment { transform: translate(0, 0) rotate(0deg); }
h1 {
  margin: 0;
  font-size: clamp(2.5rem, 4.5vw, 3.5rem);
  line-height: 1.15;
  letter-spacing: -0.02em;
  font-weight: 400;
}

@media (max-width: 767px) {
  :root { --section-height: auto; }
  .panel { min-height: 80vh; }
  .panel-grid { grid-template-columns: repeat(6, 1fr); }
  .premise-diagram, .intro-copy, .body-copy, .anatomy-set, .timeline, .focus-grid { grid-column: 1 / 7; }
  .fragment-square, .focus-grid, .resolved-square { width: 86vw; }
  .anatomy-set { grid-template-columns: 1fr; gap: 34px; }
  .step { grid-template-columns: 78px 1fr; }
  .focus-label { right: 8%; top: 12%; }
}