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

html {
  min-width: 320px;
  overflow-x: clip;
  background: var(--color-paper);
  color: var(--color-ink);
  scroll-behavior: smooth;
}

body {
  min-width: 320px;
  margin: 0;
  overflow-x: clip;
  background: var(--color-paper);
  color: var(--color-ink);
  font-family: var(--font-body);
  -webkit-font-smoothing: antialiased;
  text-rendering: geometricPrecision;
}

body::before {
  position: fixed;
  inset: 0;
  z-index: -1;
  pointer-events: none;
  content: "";
  background:
    linear-gradient(180deg, color-mix(in oklch, var(--color-paper), transparent 8%), color-mix(in oklch, var(--color-paper), transparent 0%)),
    var(--color-paper);
  opacity: 0.86;
}

a {
  color: var(--color-accent);
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
  text-decoration-style: dotted;
  text-underline-offset: 0.2em;
}

p {
  margin: 0 0 var(--space-md);
}

img,
svg,
canvas {
  max-width: 100%;
}

.skip-link {
  position: absolute;
  left: var(--space-md);
  top: var(--space-md);
  z-index: 100;
  transform: translateY(-180%);
  padding: var(--space-xs) var(--space-sm);
  background: var(--color-accent);
  color: var(--color-accent-ink);
  font-family: var(--font-display);
  font-size: var(--text-xs);
}

.skip-link:focus {
  transform: translateY(0);
}

.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 20;
  background: color-mix(in oklch, var(--color-paper), transparent 12%);
  border-bottom: var(--rule-hair) dotted color-mix(in oklch, var(--color-accent), transparent 54%);
  backdrop-filter: blur(12px);
}

.manual-home {
  padding-top: 44px;
}

.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: min(100% - 32px, 1540px);
  margin: 0 auto;
  padding: var(--space-sm) 0;
  font-family: var(--font-display);
  font-size: var(--text-xs);
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: var(--space-xs);
  color: var(--color-accent);
  font-size: var(--text-sm);
  letter-spacing: 0.02em;
  text-transform: lowercase;
}

.brand:hover {
  text-decoration: none;
}

.brand-mark {
  display: block;
  width: 34px;
  height: 34px;
  flex: 0 0 auto;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: var(--space-lg);
}

.nav-links a {
  color: color-mix(in oklch, var(--color-accent), transparent 24%);
}

.nav-links a[aria-current="page"] {
  color: var(--color-accent);
}

.manual-home {
  padding-top: 0;
}

.section-band {
  width: min(100% - 32px, 1180px);
  margin: 0 auto;
  padding: var(--space-3xl) 0;
  opacity: 0;
  transform: translateY(14px);
  transition: opacity var(--dur-slow) var(--ease-out), transform var(--dur-slow) var(--ease-out);
}

.section-band.is-visible,
.faq-section {
  opacity: 1 !important;
  transform: translateY(0) !important;
  width: min(100% - 32px, 1080px);
}

.kicker {
  margin: 0 0 var(--space-md);
  color: color-mix(in oklch, var(--color-accent), transparent 28%);
  font-family: var(--font-display);
  font-size: var(--text-xs);
  letter-spacing: 0.08em;
  line-height: 1.2;
  text-transform: uppercase;
}

.lede {
  color: var(--color-ink-muted);
  font-size: var(--text-lg);
  line-height: 1.5;
}

/* Engine scroll */
.engine-scroll-section {
  position: relative;
  height: 1520vh;
  margin: 0 0 var(--space-xl);
}

.engine-sticky {
  position: sticky;
  top: 44px;
  left: 0;
  display: grid;
  grid-template: 1fr / 1fr;
  width: min(100% - 24px, 1540px);
  height: calc(100svh - 44px - 20px);
  margin: 0 auto;
  overflow: hidden;
  background: var(--color-paper);
  border: var(--rule-hair) dotted var(--color-accent);
}

.engine-stage {
  position: absolute;
  inset: clamp(var(--space-xl), 5.6vw, var(--space-5xl)) clamp(var(--space-lg), 3vw, var(--space-3xl));
  z-index: 1;
  overflow: hidden;
  cursor: grab;
}

.engine-stage:active {
  cursor: grabbing;
}

.engine-three-canvas {
  position: absolute;
  inset: 0;
  display: block;
  width: 100%;
  height: 100%;
}

.engine-hud {
  position: absolute;
  inset: 0;
  z-index: 4;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  padding: clamp(var(--space-lg), 2.4vw, var(--space-2xl)) clamp(var(--space-xl), 3.4vw, var(--space-3xl));
  pointer-events: none;
}

.engine-hud-top {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: var(--space-lg);
  padding-bottom: var(--space-xs);
  border-bottom: var(--rule-hair) dotted color-mix(in oklch, var(--color-accent), transparent 26%);
}

.engine-fig-id,
.engine-title,
.engine-phase,
.engine-progress-label,
.engine-progress-pct {
  color: var(--color-accent);
  font-family: var(--font-display);
  font-size: var(--text-xs);
  letter-spacing: 0.08em;
  line-height: 1;
  text-transform: uppercase;
}

.engine-phase,
.engine-progress-label {
  color: color-mix(in oklch, var(--color-accent), transparent 35%);
}

.engine-hud-copy {
  position: absolute;
  top: clamp(88px, 9vw, 132px);
  left: clamp(var(--space-xl), 5.4vw, 6rem);
  z-index: 5;
  width: min(330px, 26vw);
  color: var(--color-accent);
}

.engine-hud-copy h2 {
  margin: 0 0 var(--space-md);
  font-family: var(--font-display);
  font-size: clamp(4.4rem, 6.4vw, 7.2rem);
  font-weight: 400;
  letter-spacing: 0;
  line-height: 0.76;
  text-transform: lowercase;
}

.engine-hud-copy p {
  margin: 0;
  font-family: var(--font-display);
  font-size: var(--text-base);
  line-height: 1.45;
}

.engine-part-label {
  position: absolute;
  top: 50%;
  right: clamp(var(--space-xl), 5vw, 7rem);
  z-index: 5;
  width: clamp(270px, 25vw, 420px);
  min-height: 216px;
  padding: var(--space-md) var(--space-lg) var(--space-lg);
  transform: translateY(calc(-50% + 10px));
  background:
    linear-gradient(180deg, color-mix(in oklch, var(--color-paper), transparent 4%), color-mix(in oklch, var(--color-accent-wash), transparent 28%)),
    var(--color-paper);
  border: var(--rule-hair) dotted color-mix(in oklch, var(--color-accent), transparent 18%);
  box-shadow: 0 18px 48px var(--color-shadow);
  opacity: 0;
  transition: opacity var(--dur-slow) var(--ease-out), transform var(--dur-slow) var(--ease-out);
}

.engine-hud.is-label-visible .engine-part-label {
  opacity: 1;
  transform: translateY(-50%);
}

.engine-part-label::before {
  display: block;
  margin-bottom: var(--space-sm);
  padding-bottom: var(--space-xs);
  border-bottom: var(--rule-hair) dotted color-mix(in oklch, var(--color-accent), transparent 42%);
  color: color-mix(in oklch, var(--color-accent), transparent 34%);
  content: "CRATE DETAIL";
  font-family: var(--font-display);
  font-size: var(--text-xs);
  letter-spacing: 0.08em;
  line-height: 1;
  text-transform: uppercase;
}

.engine-part-crate {
  display: block;
  min-height: 1.2em;
  margin-bottom: var(--space-2xs);
  color: color-mix(in oklch, var(--color-accent), transparent 28%);
  font-family: var(--font-display);
  font-size: var(--text-xs);
  letter-spacing: 0.06em;
  text-transform: lowercase;
}

.engine-part-name {
  display: block;
  margin-bottom: var(--space-sm);
  color: var(--color-accent);
  font-family: var(--font-display);
  font-size: clamp(1rem, 1.7vw, 1.28rem);
  letter-spacing: 0.05em;
  line-height: 1.1;
  text-transform: uppercase;
}

.engine-part-desc {
  margin: 0;
  color: var(--color-ink);
  font-size: var(--text-base);
  line-height: 1.48;
}

.engine-hud-bottom {
  display: flex;
  align-items: center;
  gap: var(--space-md);
  padding-top: var(--space-xs);
  border-top: var(--rule-hair) dotted color-mix(in oklch, var(--color-accent), transparent 26%);
}

.engine-progress-track {
  flex: 1;
  height: 3px;
  overflow: hidden;
  background: color-mix(in oklch, var(--color-accent), transparent 74%);
}

.engine-progress-fill {
  width: 0%;
  height: 100%;
  background: var(--color-accent);
  transition: width 80ms linear;
}

.engine-part-rail {
  position: absolute;
  top: 50%;
  right: clamp(var(--space-sm), 1.2vw, var(--space-lg));
  z-index: 7;
  display: flex;
  flex-direction: column;
  gap: 4px;
  margin: 0;
  padding: 0;
  list-style: none;
  transform: translateY(-50%);
}

.engine-part-rail li {
  display: flex;
  justify-content: flex-end;
  width: 34px;
  height: 10px;
}

.engine-rail-button {
  display: flex;
  justify-content: flex-end;
  width: 30px;
  height: 10px;
  padding: 0;
  cursor: pointer;
  background: transparent;
  border: 0;
}

.engine-rail-button::before {
  display: block;
  width: 16px;
  height: 2px;
  margin-top: 4px;
  background: color-mix(in oklch, var(--color-accent), transparent 64%);
  content: "";
  transition: background var(--dur-fast) var(--ease-out), width var(--dur-fast) var(--ease-out);
}

.engine-rail-button:hover::before,
.engine-rail-button:focus-visible::before,
.engine-part-rail li.is-past .engine-rail-button::before {
  background: color-mix(in oklch, var(--color-accent), transparent 38%);
}

.engine-rail-button:focus-visible {
  outline: var(--rule-thin) solid color-mix(in oklch, var(--color-accent), transparent 20%);
  outline-offset: 2px;
}

.engine-part-rail li.is-active .engine-rail-button::before {
  width: 30px;
  background: var(--color-accent);
}

.engine-rotate-hint {
  position: absolute;
  bottom: calc(var(--space-md) + 40px);
  left: 50%;
  z-index: 6;
  display: flex;
  align-items: center;
  gap: var(--space-xs);
  transform: translateX(-50%);
  color: color-mix(in oklch, var(--color-accent), transparent 40%);
  font-family: var(--font-display);
  font-size: 0.65rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  pointer-events: none;
  opacity: 0.7;
}

/* FAQ */
.faq-section {
  width: min(100% - 32px, 1080px);
  padding-top: 0;
}

.faq-grid {
  display: grid;
  grid-template-columns: minmax(200px, 0.4fr) minmax(0, 1fr);
  gap: var(--space-3xl);
  align-items: start;
}

.faq-questions {
  display: flex;
  flex-direction: column;
  gap: 0;
  padding-top: var(--space-2xl);
}

.faq-questions .kicker {
  margin-bottom: var(--space-lg);
}

.faq-q {
  display: flex;
  align-items: center;
  height: 5rem;
  padding: 0;
  border: 0;
  background: transparent;
  color: var(--color-ink);
  font-family: var(--font-body);
  font-size: var(--text-xl);
  font-weight: 600;
  text-align: left;
  cursor: pointer;
  transform-origin: left center;
  transform: translateX(calc(var(--dist, 2) * -2px)) scale(calc(1 - var(--dist, 2) * 0.03)) rotate(calc(var(--rot, 0) * -1deg));
  opacity: calc(1 - var(--dist, 2) * 0.2);
  filter: blur(calc(var(--dist, 2) * 1px));
  transition: all 300ms cubic-bezier(0.16, 1, 0.3, 1);
  user-select: none;
}

.faq-q:hover {
  transform: translateX(0) scale(1) rotate(0deg);
  opacity: 1;
  filter: blur(0);
}

.faq-q.is-active {
  --dist: 0;
  --rot: 0;
  color: var(--color-ink);
  opacity: 1;
  filter: blur(0);
  transform: translateX(0) scale(1) rotate(0deg);
}

.faq-q[data-index="0"] {
  --dist: 3;
  --rot: 4;
}

.faq-q[data-index="1"] {
  --dist: 2;
  --rot: 2.5;
}

.faq-q[data-index="2"] {
  --dist: 0;
  --rot: 0;
}

.faq-q[data-index="3"] {
  --dist: 2;
  --rot: -2.5;
}

.faq-q[data-index="4"] {
  --dist: 3;
  --rot: -4;
}

.faq-q[data-index="5"] {
  --dist: 4;
  --rot: -5.5;
}

.faq-q[data-index="6"] {
  --dist: 3;
  --rot: -4;
}

.faq-q[data-index="7"] {
  --dist: 4;
  --rot: -5.5;
}

.faq-q.is-active~.faq-q {
  --dist: 2;
  --rot: -2.5;
}

.faq-q.is-active~.faq-q~.faq-q {
  --dist: 3;
  --rot: -4;
}

.faq-q.is-active~.faq-q~.faq-q~.faq-q {
  --dist: 4;
  --rot: -5.5;
}

.faq-q.is-active {
  --dist: 0 !important;
  --rot: 0 !important;
}

.faq-q:has(~ .faq-q.is-active) {
  --rot: 2.5;
  --dist: 2;
}

.faq-q:has(~ .faq-q ~ .faq-q.is-active) {
  --rot: 4;
  --dist: 3;
}

.faq-q:has(~ .faq-q ~ .faq-q ~ .faq-q.is-active) {
  --rot: 5.5;
  --dist: 4;
}

.faq-answer-panel {
  border: var(--rule-hair) solid color-mix(in oklch, var(--color-ink), transparent 88%);
  background: var(--color-paper);
  border-radius: var(--radius-sm);
  margin-top: var(--space-2xl);
}

.faq-answer-header {
  display: grid;
  grid-template-columns: 2rem 1fr;
  gap: var(--space-sm);
  padding: var(--space-md);
  border-bottom: var(--rule-hair) solid color-mix(in oklch, var(--color-ink), transparent 88%);
}

.faq-answer-header span:first-child {
  font-family: var(--font-display);
  font-size: var(--text-xs);
  text-transform: uppercase;
  color: var(--color-ink-muted);
}

.faq-answer-header span:last-child {
  font-family: var(--font-display);
  font-size: var(--text-sm);
  text-transform: uppercase;
  color: var(--color-ink);
}

.faq-answer-body {
  display: grid;
  grid-template-columns: 2rem 1fr;
  gap: var(--space-sm);
  padding: var(--space-md);
}

.faq-answer-body>span {
  font-family: var(--font-display);
  font-size: var(--text-xs);
  text-transform: uppercase;
  color: var(--color-ink-muted);
}

.faq-answer-body p {
  margin: 0;
  font-size: var(--text-md);
  line-height: 1.65;
  color: var(--color-ink);
  animation: blur-in 500ms var(--ease-out) both;
}

.faq-answer-body a {
  color: var(--color-accent);
}

@media (max-width: 620px) {
  .faq-grid {
    grid-template-columns: 1fr;
    gap: 0;
  }

  .faq-questions {
    padding-top: 0;
    gap: 0;
  }

  .faq-q {
    transform: none;
    filter: none;
    height: auto;
    padding: var(--space-sm) 0;
    font-size: var(--text-base);
    opacity: 0.5;
    border-bottom: var(--rule-hair) dotted var(--color-rule);
    transition: opacity 200ms, color 200ms;
  }

  .faq-q.is-active {
    opacity: 1;
    color: var(--color-accent);
  }

  .faq-answer-panel {
    margin-top: var(--space-md);
  }
}

/* Article pages */
.why-article,
.imp-article {
  color: var(--color-ink);
}

.why-callout,
.imp-callout {
  border-left-color: var(--color-accent);
}

.why-section-marker,
.imp-section-marker {
  color: color-mix(in oklch, var(--color-accent), transparent 34%);
}

.footer {
  display: flex;
  justify-content: space-between;
  gap: var(--space-md);
  width: min(100% - 32px, 1180px);
  margin: 0 auto;
  padding: var(--space-xl) 0 var(--space-2xl);
  border-top: var(--rule-hair) solid var(--color-rule);
  color: var(--color-ink-muted);
  font-family: var(--font-display);
  font-size: var(--text-xs);
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

.footer p {
  margin: 0;
}

@keyframes blur-in {
  from {
    opacity: 0;
    filter: blur(8px);
  }

  to {
    opacity: 1;
    filter: blur(0);
  }
}

@media (max-width: 900px) {
  .nav {
    align-items: flex-start;
    flex-direction: column;
    gap: var(--space-sm);
  }

  .engine-sticky {
    width: min(100% - 12px, 1540px);
  }

  .engine-hud-copy {
    width: min(270px, 54vw);
  }

  .engine-hud-copy h2 {
    font-size: clamp(3.2rem, 13vw, 5.8rem);
  }

  .engine-part-label {
    top: auto;
    right: var(--space-lg);
    bottom: 74px;
    left: var(--space-lg);
    width: auto;
    min-height: 0;
    transform: translateY(10px);
  }

  .engine-hud.is-label-visible .engine-part-label {
    transform: translateY(0);
  }

  .engine-part-desc {
    font-size: var(--text-sm);
  }

  .faq-grid {
    grid-template-columns: 1fr;
    gap: var(--space-lg);
  }
}

@media (max-width: 620px) {

  .section-band,
  .faq-section,
  .footer {
    width: min(100% - 24px, 1180px);
  }

  .nav {
    width: min(100% - 24px, 1540px);
  }

  .nav-links {
    gap: var(--space-md);
  }

  .engine-hud {
    padding: var(--space-md);
  }

  .engine-stage {
    inset: 72px var(--space-sm) 84px;
  }

  .engine-hud-top,
  .engine-hud-bottom {
    gap: var(--space-sm);
  }

  .engine-title {
    display: none;
  }

  .engine-hud-copy {
    top: 72px;
    left: var(--space-lg);
  }

  .engine-hud-copy p {
    font-size: var(--text-sm);
  }

  .engine-part-rail {
    right: var(--space-xs);
  }

  .faq-answer-header,
  .faq-answer-body {
    grid-template-columns: 1fr;
    gap: var(--space-xs);
  }

  .faq-answer-body p {
    font-size: var(--text-md);
  }

  .footer {
    flex-direction: column;
  }
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  *,
  *::before,
  *::after {
    transition-duration: 1ms !important;
    animation-duration: 1ms !important;
    animation-iteration-count: 1 !important;
  }

  .section-band {
    opacity: 1;
    transform: none;
  }
}