@import url("../../tokens.css");

*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; overflow-x: clip; }
body {
  margin: 0;
  overflow-x: clip;
  color: var(--color-ink);
  background: var(--color-paper);
  font-family: var(--font-body);
  font-size: var(--text-base);
  line-height: 1.65;
  padding-block-end: var(--space-3xl);
}
img { display: block; max-width: 100%; height: auto; }
a { color: inherit; text-underline-offset: 0.2em; }
button, a { -webkit-tap-highlight-color: transparent; }
button { font: inherit; }
h1, h2, h3 { margin: 0; font-family: var(--font-display); font-style: normal; overflow-wrap: anywhere; min-width: 0; }
h1, h2 { letter-spacing: -0.035em; }
p { margin: 0; }
ul, ol { margin: 0; padding: 0; }
.container { width: min(var(--page-max), calc(100% - 2 * var(--page-gutter))); margin-inline: auto; }
.skip-link { position: fixed; inset: var(--space-sm) auto auto var(--space-sm); z-index: var(--z-tooltip); transform: translateY(-160%); background: var(--color-paper); padding: var(--space-sm) var(--space-md); border: var(--rule-strong) solid var(--color-focus); }
.skip-link:focus { transform: translateY(0); }

.nav-shell {
  position: fixed;
  inset: 0 0 auto;
  z-index: var(--z-sticky-nav);
  min-height: var(--nav-height);
  background-color: color-mix(in oklch, var(--color-paper) 92%, transparent);
  border-block-end: var(--rule-hair) solid var(--color-rule-2);
  backdrop-filter: saturate(1.2) blur(14px);
  transition: background-color var(--dur-nav) var(--ease-out), border-color var(--dur-nav) var(--ease-out), backdrop-filter var(--dur-nav) var(--ease-out);
}
.nav-shell.is-floating { background-color: transparent; border-color: transparent; backdrop-filter: blur(0); }
.nav-inner {
  min-height: var(--nav-height);
  display: grid;
  grid-template-columns: auto minmax(0, 1fr) auto;
  align-items: center;
  gap: var(--space-lg);
  padding-inline: var(--page-gutter);
  max-width: 62rem;
  margin-inline: auto;
  transition: transform var(--dur-nav) var(--ease-out), background-color var(--dur-nav) var(--ease-out), border-radius var(--dur-nav) var(--ease-out), box-shadow var(--dur-nav) var(--ease-out), backdrop-filter var(--dur-nav) var(--ease-out);
}
.nav-shell.is-floating .nav-inner { border-radius: var(--radius-pill); transform: translateY(var(--space-sm)); background-color: color-mix(in oklch, var(--color-night) 92%, transparent); color: var(--color-night-ink); backdrop-filter: blur(18px); box-shadow: 0 var(--space-xs) var(--space-lg) var(--color-shadow), inset 0 0 0 var(--rule-hair) var(--color-inset-light); }
.brand { display: inline-flex; align-items: center; gap: var(--space-xs); text-decoration: none; white-space: nowrap; font-family: var(--font-display); font-weight: 900; }
.brand img { width: 2.25rem; height: 2.25rem; object-fit: cover; border-radius: 50%; }
.nav-links { display: flex; justify-content: center; gap: clamp(var(--space-sm), 2vw, var(--space-lg)); }
.nav-links a, .mobile-menu a, .footer a { white-space: nowrap; text-decoration: none; }
.nav-links a { font-size: var(--text-sm); position: relative; }
.nav-links a::after { content: ""; position: absolute; inset: auto 0 -0.35rem; height: var(--rule-strong); background: var(--color-coral); transform: scaleX(0); transform-origin: left; transition: transform var(--dur-short) var(--ease-out); }
.nav-links a:hover::after, .nav-links a:focus-visible::after, .nav-links a[aria-current="page"]::after { transform: scaleX(1); }
.menu-toggle { display: none; width: 2.75rem; height: 2.75rem; border: var(--rule-hair) solid var(--color-rule); background: var(--color-paper); color: var(--color-ink); border-radius: 50%; cursor: pointer; }
.menu-toggle::before { content: "菜单"; font-size: var(--text-xs); }
.mobile-menu { position: fixed; top: calc(var(--nav-height) + var(--space-sm)); left: var(--page-gutter); right: var(--page-gutter); z-index: var(--z-dropdown); display: grid; gap: var(--space-2xs); padding: var(--space-sm); background: var(--color-night); color: var(--color-night-ink); border-radius: var(--radius-lg); }
.mobile-menu[hidden] { display: none; }
.mobile-menu a { min-height: 2.75rem; display: flex; align-items: center; padding-inline: var(--space-md); border-radius: var(--radius-sm); }

.btn {
  min-height: 2.9rem;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-xs);
  padding: var(--space-sm) var(--space-lg);
  border: var(--rule-strong) solid var(--color-ink);
  border-radius: var(--radius-sm);
  background: var(--color-paper);
  color: var(--color-ink);
  font-weight: 700;
  line-height: 1;
  text-decoration: none;
  white-space: nowrap;
  cursor: pointer;
  transition: transform var(--dur-micro) var(--ease-out), background-color var(--dur-short) var(--ease-out), color var(--dur-short) var(--ease-out), border-color var(--dur-short) var(--ease-out), opacity var(--dur-short) var(--ease-out);
}
.btn:hover { transform: translateY(-1px); }
.btn:active { transform: translateY(1px) scale(0.99); }
.btn:focus-visible, button:focus-visible, a:focus-visible, summary:focus-visible { outline: var(--rule-strong) solid var(--color-focus); outline-offset: var(--space-2xs); }
.btn[aria-disabled="true"], .btn:disabled { opacity: 0.46; cursor: not-allowed; transform: none; pointer-events: none; }
.btn[data-state="loading"] { opacity: 0.72; cursor: wait; }
.btn[data-state="error"] { border-color: var(--color-error); }
.btn[data-state="success"] { border-color: var(--color-success); }
.btn--primary { position: relative; overflow: hidden; background: var(--color-night); color: var(--color-night-ink); border-color: var(--color-night); }
.btn--primary::after { content: ""; position: absolute; inset: -60% auto -60% -35%; width: 22%; background: color-mix(in oklch, var(--color-paper) 48%, transparent); transform: skewX(-18deg) translateX(0); transition: transform var(--dur-long) var(--ease-out); pointer-events: none; }
.btn--primary:hover::after, .btn--primary:focus-visible::after { transform: skewX(-18deg) translateX(650%); }
.btn--gold { background: var(--color-gold); border-color: var(--color-gold); color: var(--color-night); }
.btn--ghost-light { background: transparent; border-color: color-mix(in oklch, var(--color-night-ink) 55%, transparent); color: var(--color-night-ink); }
.btn--small { min-height: 2.55rem; padding-inline: var(--space-md); font-size: var(--text-sm); }

.hero {
  position: relative;
  min-height: clamp(43rem, 82dvh, 58rem);
  display: grid;
  align-items: end;
  color: var(--color-night-ink);
  background: var(--color-night);
  isolation: isolate;
  padding-block: var(--space-xl) var(--space-2xl);
}
.hero-media { position: absolute; inset: 0; z-index: -2; overflow: hidden; }
.hero-media img { width: 100%; height: 100%; object-fit: cover; object-position: 30% 18%; transform: scale(1.02) translate3d(0, var(--parallax-y, 0px), 0); animation: hero-settle 12s var(--ease-out) both; }
.hero-media::after { content: ""; position: absolute; inset: 0; background: linear-gradient(90deg, var(--color-overlay-strong), var(--color-overlay-soft)); }
@keyframes hero-settle { to { transform: scale(1.045) translate3d(0, var(--parallax-y, 0px), 0); } }
.hero-grid { display: grid; grid-template-columns: minmax(0, 7fr) minmax(0, 5fr); gap: var(--space-2xl); align-items: end; margin-block-start: var(--nav-height); }
.hero-copy { max-width: 48rem; }
.hero-logo { width: min(18rem, 72vw); aspect-ratio: 2.2 / 1; object-fit: cover; object-position: center; border-radius: var(--radius-sm); margin-block-end: var(--space-lg); }
.tag-list { display: flex; flex-wrap: wrap; gap: var(--space-xs); margin-block-end: var(--space-md); }
.tag { display: inline-flex; align-items: center; min-height: 1.9rem; padding-inline: var(--space-sm); border: var(--rule-hair) solid color-mix(in oklch, var(--color-night-ink) 38%, transparent); border-radius: var(--radius-pill); font-size: var(--text-sm); white-space: nowrap; }
.tag--coral { border-color: var(--color-coral); color: var(--color-paper); background: color-mix(in oklch, var(--color-coral) 68%, transparent); }
.hero h1 { font-size: var(--text-display); line-height: 1.02; max-width: 13ch; }
.hero h1 span { display: block; margin-block-start: var(--space-sm); font-family: var(--font-body); font-size: clamp(1rem, 2vw, 1.45rem); font-weight: 400; letter-spacing: 0.02em; }
.hero-lede { max-width: 44rem; margin-block-start: var(--space-lg); font-size: var(--text-md); color: color-mix(in oklch, var(--color-night-ink) 88%, transparent); }
.hero-actions { display: flex; flex-wrap: wrap; gap: var(--space-sm); margin-block-start: var(--space-lg); }
.hero-facts { align-self: end; display: grid; gap: var(--space-xs); padding: var(--space-lg); background: color-mix(in oklch, var(--color-night) 84%, transparent); border-inline-start: var(--rule-strong) solid var(--color-gold); backdrop-filter: blur(10px); }
.hero-fact { display: grid; grid-template-columns: minmax(0, 1fr) auto; gap: var(--space-md); align-items: baseline; padding-block: var(--space-sm); border-block-end: var(--rule-hair) solid color-mix(in oklch, var(--color-night-ink) 16%, transparent); }
.hero-fact:last-child { border-block-end: 0; }
.hero-fact dt { color: color-mix(in oklch, var(--color-night-ink) 66%, transparent); font-size: var(--text-sm); }
.hero-fact dd { margin: 0; text-align: right; font-weight: 700; font-variant-numeric: tabular-nums; }

.section { padding-block: var(--space-3xl); }
.section--tight { padding-block: var(--space-2xl); }
.section--paper-2 { background: var(--color-paper-2); }
.section--night { background: var(--color-night); color: var(--color-night-ink); }
.section-head { display: grid; grid-template-columns: minmax(0, 1.15fr) minmax(16rem, 0.85fr); gap: var(--space-xl); align-items: end; margin-block-end: var(--space-2xl); }
.section-head h2, .page-intro h1 { font-size: clamp(2.15rem, 4vw, 4rem); line-height: 1.08; }
.section-head p { max-width: 48ch; color: var(--color-muted); }
.section--night .section-head p { color: color-mix(in oklch, var(--color-night-ink) 66%, transparent); }
.info-grid { display: grid; grid-template-columns: repeat(6, minmax(0, 1fr)); margin: 0; border-block: var(--rule-hair) solid var(--color-rule); }
.info-item { min-width: 0; padding: var(--space-lg) var(--space-md); border-inline-end: var(--rule-hair) solid var(--color-rule); }
.info-item:last-child { border: 0; }
.info-item dt { font-size: var(--text-sm); color: var(--color-muted); }
.info-item dd { margin: var(--space-xs) 0 0; font-weight: 700; overflow-wrap: anywhere; }

.story-layout { display: grid; grid-template-columns: minmax(0, 5fr) minmax(0, 7fr); gap: var(--space-2xl); align-items: start; }
.story-copy { position: sticky; top: calc(var(--nav-height) + var(--space-xl)); display: grid; gap: var(--space-lg); }
.story-copy h2 { font-size: clamp(2rem, 4vw, 3.5rem); line-height: 1.1; }
.story-copy p { color: var(--color-muted); max-width: 56ch; }
.visual-stack { display: grid; gap: var(--space-xl); }
.scene-card { margin: 0; background: var(--color-night); color: var(--color-night-ink); }
.scene-card img { width: 100%; aspect-ratio: 4 / 3; object-fit: cover; }
.scene-card figcaption { padding: var(--space-md) var(--space-lg) var(--space-lg); }
.scene-card strong { display: block; font-family: var(--font-display); font-size: var(--text-lg); }
.scene-card span { display: block; margin-block-start: var(--space-xs); color: color-mix(in oklch, var(--color-night-ink) 66%, transparent); }
.dialogue-box { position: relative; margin-block-start: calc(var(--space-xl) * -1); margin-inline: var(--space-lg); padding: var(--space-lg); background: color-mix(in oklch, var(--color-night) 94%, transparent); color: var(--color-night-ink); border: var(--rule-hair) solid color-mix(in oklch, var(--color-gold) 72%, transparent); }
.speaker { display: inline-block; margin-block-end: var(--space-xs); color: var(--color-gold); font-weight: 700; }
.choices { display: grid; gap: var(--space-xs); margin-block-start: var(--space-md); }
.choice { display: flex; justify-content: space-between; align-items: center; min-height: 2.75rem; padding-inline: var(--space-md); border: var(--rule-hair) solid color-mix(in oklch, var(--color-night-ink) 26%, transparent); text-decoration: none; }
.choice:hover, .choice:focus-visible { border-color: var(--color-coral); }

.feature-grid { display: grid; grid-template-columns: 1.4fr 1fr 1fr; gap: var(--space-md); }
.feature { min-width: 0; padding: var(--space-xl); background: var(--color-paper); border-block-start: var(--rule-strong) solid var(--color-rule); transition: transform var(--dur-short) var(--ease-out), box-shadow var(--dur-short) var(--ease-out); }
.feature:first-child { grid-row: span 2; background: var(--color-night); color: var(--color-night-ink); border-color: var(--color-gold); }
.feature:hover { transform: translateY(-3px); box-shadow: 0 var(--space-xs) var(--space-lg) var(--color-shadow-soft); }
.feature-mark { font-family: var(--font-body); font-size: var(--text-xs); color: var(--color-coral); }
.feature h3 { margin-block-start: var(--space-md); font-size: var(--text-xl); line-height: 1.2; }
.feature p { margin-block-start: var(--space-sm); color: var(--color-muted); }
.feature:first-child p { color: color-mix(in oklch, var(--color-night-ink) 68%, transparent); }

.gallery-grid { display: grid; grid-template-columns: repeat(12, minmax(0, 1fr)); gap: var(--space-md); }
.gallery-item { grid-column: span 4; padding: 0; border: 0; background: var(--color-paper-2); cursor: zoom-in; overflow: hidden; }
.gallery-item:nth-child(1), .gallery-item:nth-child(5) { grid-column: span 8; }
.gallery-item img { width: 100%; aspect-ratio: 16 / 10; object-fit: cover; transition: transform var(--dur-long) var(--ease-out), opacity var(--dur-short) var(--ease-out); }
.gallery-item:hover img, .gallery-item:focus-visible img { transform: scale(1.025); opacity: 0.92; }
.gallery-item[hidden] { display: none; }
.gallery-tabs { display: flex; flex-wrap: wrap; gap: var(--space-xs); margin-block-end: var(--space-xl); }
.tab { min-height: 2.75rem; padding-inline: var(--space-md); border: var(--rule-hair) solid var(--color-rule); border-radius: var(--radius-pill); background: var(--color-paper); color: var(--color-ink); cursor: pointer; white-space: nowrap; }
.tab[aria-selected="true"] { background: var(--color-night); border-color: var(--color-night); color: var(--color-night-ink); }

.download-panel { display: grid; grid-template-columns: minmax(0, 1.2fr) minmax(17rem, 0.8fr); gap: var(--space-2xl); align-items: end; padding: var(--space-2xl); background: var(--color-night); color: var(--color-night-ink); border-block-start: var(--rule-strong) solid var(--color-gold); }
.download-panel h2 { font-size: clamp(2rem, 4vw, 3.75rem); line-height: 1.08; }
.download-panel p { margin-block-start: var(--space-md); color: color-mix(in oklch, var(--color-night-ink) 70%, transparent); }
.download-facts { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); border: var(--rule-hair) solid color-mix(in oklch, var(--color-night-ink) 20%, transparent); }
.download-facts div { padding: var(--space-md); border: var(--rule-hair) solid color-mix(in oklch, var(--color-night-ink) 10%, transparent); }
.download-facts span { display: block; font-size: var(--text-sm); color: color-mix(in oklch, var(--color-night-ink) 58%, transparent); }
.download-facts strong { font-size: var(--text-lg); font-variant-numeric: tabular-nums; }

.timeline { list-style: none; display: grid; gap: 0; max-width: 64rem; margin-inline-start: auto; }
.timeline li { display: grid; grid-template-columns: 10rem minmax(0, 1fr); gap: var(--space-xl); padding-block: var(--space-lg); border-block-end: var(--rule-hair) solid var(--color-rule); }
.timeline time { font-family: var(--font-body); color: var(--color-coral); font-variant-numeric: tabular-nums; }
.fit-grid { display: grid; grid-template-columns: 1.2fr 1fr 0.8fr; gap: var(--space-md); }
.fit-card { padding: var(--space-xl); background: var(--color-paper); border-block-start: var(--rule-strong) solid var(--color-accent); }
.fit-card h3 { font-size: var(--text-xl); }
.fit-card p { margin-block-start: var(--space-sm); color: var(--color-muted); }

.faq-list { max-width: 64rem; margin-inline-start: auto; border-block-start: var(--rule-hair) solid var(--color-rule); }
.faq-item { border-block-end: var(--rule-hair) solid var(--color-rule); }
.faq-item summary { position: relative; list-style: none; cursor: pointer; padding: var(--space-lg) calc(var(--space-xl) + var(--space-md)) var(--space-lg) 0; font-family: var(--font-display); font-size: var(--text-lg); font-weight: 700; }
.faq-item summary::-webkit-details-marker { display: none; }
.faq-item summary::after { content: "+"; position: absolute; inset: 50% 0 auto auto; transform: translateY(-50%); font-family: var(--font-body); color: var(--color-coral); }
.faq-item[open] summary::after { content: "−"; }
.faq-answer { padding: 0 0 var(--space-lg); color: var(--color-muted); max-width: 64ch; }

.final-cta { padding-block: var(--space-4xl); background: var(--color-night); color: var(--color-night-ink); }
.final-cta-inner { max-width: 58rem; }
.final-cta h2 { font-size: clamp(2.4rem, 5.5vw, 5.25rem); line-height: 1.02; }
.final-cta p { margin-block-start: var(--space-lg); max-width: 54ch; color: color-mix(in oklch, var(--color-night-ink) 68%, transparent); }
.final-cta small { display: block; margin-block-start: var(--space-lg); color: color-mix(in oklch, var(--color-night-ink) 52%, transparent); }

.footer { padding-block: var(--space-3xl) var(--space-2xl); }
.footer-statement { max-width: 28ch; font-family: var(--font-display); font-size: clamp(2rem, 4.5vw, 4.2rem); line-height: 1.06; }
.footer-grid { display: grid; grid-template-columns: minmax(15rem, 1.15fr) minmax(0, 0.85fr); gap: var(--space-2xl); margin-block-start: var(--space-2xl); padding-block-start: var(--space-lg); border-block-start: var(--rule-hair) solid var(--color-rule); }
.footer-links { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: var(--space-sm) var(--space-lg); }
.footer-note { color: var(--color-muted); font-size: var(--text-sm); }
.footer-note p + p { margin-block-start: var(--space-xs); }

.sticky-cta { position: fixed; inset: auto 0 0; z-index: var(--z-sticky); display: flex; align-items: center; justify-content: space-between; gap: var(--space-md); padding: var(--space-xs) max(var(--page-gutter), env(safe-area-inset-left)) calc(var(--space-xs) + env(safe-area-inset-bottom)); background: color-mix(in oklch, var(--color-paper) 94%, transparent); border-block-start: var(--rule-hair) solid var(--color-rule); backdrop-filter: blur(14px); }
.sticky-cta span { font-size: var(--text-sm); color: var(--color-muted); }

.page-intro { padding-block: calc(var(--nav-height) + var(--space-3xl)) var(--space-2xl); background: var(--color-night); color: var(--color-night-ink); }
.page-intro p { margin-block-start: var(--space-md); max-width: 58ch; color: color-mix(in oklch, var(--color-night-ink) 68%, transparent); }
.breadcrumb { display: flex; flex-wrap: wrap; gap: var(--space-xs); margin-block-end: var(--space-lg); font-size: var(--text-sm); color: color-mix(in oklch, var(--color-night-ink) 62%, transparent); }
.platform-grid, .guide-grid, .edition-grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: var(--space-lg); }
.platform-card, .guide-card, .edition-card { position: relative; min-width: 0; padding: var(--space-xl); border: var(--rule-hair) solid var(--color-rule); background: var(--color-paper); }
.platform-card--recommended { border-block-start: var(--rule-strong) solid var(--color-coral); }
.recommend-badge { position: absolute; inset: var(--space-md) var(--space-md) auto auto; font-size: var(--text-xs); color: var(--color-coral); }
.platform-card h2, .guide-card h2, .edition-card h3 { font-size: var(--text-xl); }
.platform-card p, .guide-card p, .edition-card p { margin-block: var(--space-sm) var(--space-lg); color: var(--color-muted); }
.platform-card[aria-disabled="true"] { opacity: 0.62; }
.steps { list-style: none; display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: var(--space-lg); counter-reset: install; }
.steps li { counter-increment: install; position: relative; padding: var(--space-xl); border-block-start: var(--rule-strong) solid var(--color-rule); }
.steps li::before { content: counter(install, decimal-leading-zero); display: block; margin-block-end: var(--space-md); font-family: var(--font-body); color: var(--color-coral); }
.requirements { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: var(--space-lg); }
.requirements table { width: 100%; border-collapse: collapse; }
.requirements caption { text-align: left; padding-block-end: var(--space-md); font-family: var(--font-display); font-size: var(--text-xl); font-weight: 700; }
.requirements th, .requirements td { padding: var(--space-sm); text-align: left; vertical-align: top; border-block-end: var(--rule-hair) solid var(--color-rule); }
.requirements th { width: 34%; color: var(--color-muted); font-weight: 400; }
.guide-layout { display: grid; grid-template-columns: minmax(12rem, 0.28fr) minmax(0, 0.72fr); gap: var(--space-2xl); align-items: start; }
.toc { position: sticky; top: calc(var(--nav-height) + var(--space-xl)); display: grid; gap: var(--space-xs); padding-block-start: var(--space-sm); border-block-start: var(--rule-strong) solid var(--color-gold); }
.toc a { text-decoration: none; white-space: nowrap; }
.article { max-width: 54rem; }
.article section + section { margin-block-start: var(--space-3xl); }
.article h2 { font-size: clamp(1.8rem, 3vw, 2.75rem); line-height: 1.15; }
.article h3 { margin-block-start: var(--space-xl); font-size: var(--text-xl); }
.article p, .article ul, .article ol { margin-block-start: var(--space-md); }
.article ul, .article ol { padding-inline-start: var(--space-lg); }
.article li + li { margin-block-start: var(--space-xs); }
.article table { width: 100%; margin-block-start: var(--space-lg); border-collapse: collapse; }
.article th, .article td { padding: var(--space-sm); text-align: left; vertical-align: top; border-block-end: var(--rule-hair) solid var(--color-rule); }
.notice { padding: var(--space-lg); border-inline-start: var(--rule-strong) solid var(--color-coral); background: var(--color-paper-2); }

.lightbox { width: min(92vw, 74rem); max-height: 92dvh; padding: 0; border: 0; background: transparent; color: var(--color-night-ink); }
.lightbox::backdrop { background: var(--color-overlay); }
.lightbox figure { margin: 0; display: grid; gap: var(--space-sm); }
.lightbox img { max-height: 78dvh; width: 100%; object-fit: contain; background: var(--color-night); }
.lightbox figcaption { text-align: center; }
.lightbox-close, .lightbox-prev, .lightbox-next { position: fixed; z-index: var(--z-modal); width: 2.75rem; height: 2.75rem; display: grid; place-items: center; border: var(--rule-hair) solid color-mix(in oklch, var(--color-night-ink) 40%, transparent); background: var(--color-night); color: var(--color-night-ink); cursor: pointer; }
.lightbox-close { inset: var(--space-lg) var(--space-lg) auto auto; }
.lightbox-prev { inset: 50% auto auto var(--space-lg); transform: translateY(-50%); }
.lightbox-next { inset: 50% var(--space-lg) auto auto; transform: translateY(-50%); }
.back-to-top { position: fixed; inset: auto var(--page-gutter) 5.5rem auto; z-index: var(--z-raised); width: 2.75rem; height: 2.75rem; border: var(--rule-hair) solid var(--color-rule); background: var(--color-paper); color: var(--color-ink); border-radius: 50%; cursor: pointer; opacity: 0; pointer-events: none; transform: translateY(var(--space-sm)); transition: opacity var(--dur-short) var(--ease-out), transform var(--dur-short) var(--ease-out); }
.back-to-top.is-visible { opacity: 1; pointer-events: auto; transform: none; }

:where(.tab, .gallery-item, .menu-toggle, .lightbox-close, .lightbox-prev, .lightbox-next, .back-to-top):active { transform: scale(0.98); }
:where(.tab, .gallery-item, .menu-toggle, .lightbox-close, .lightbox-prev, .lightbox-next, .back-to-top):disabled { opacity: 0.46; cursor: not-allowed; }
:where(.tab, .gallery-item, .menu-toggle, .lightbox-close, .lightbox-prev, .lightbox-next, .back-to-top)[data-state="loading"] { opacity: 0.72; cursor: wait; }
:where(.tab, .gallery-item, .menu-toggle, .lightbox-close, .lightbox-prev, .lightbox-next, .back-to-top)[data-state="error"] { border-color: var(--color-error); }
:where(.tab, .gallery-item, .menu-toggle, .lightbox-close, .lightbox-prev, .lightbox-next, .back-to-top)[data-state="success"] { border-color: var(--color-success); }
.choice { white-space: nowrap; }
.choice span:first-child { min-width: 0; overflow: hidden; text-overflow: ellipsis; }

@media (max-width: 64rem) {
  .nav-links { display: none; }
  .nav-inner { grid-template-columns: minmax(0, 1fr) auto; }
  .menu-toggle { display: grid; place-items: center; }
  .hero-grid, .story-layout, .download-panel, .guide-layout, .footer-grid { grid-template-columns: minmax(0, 1fr); }
  .hero { min-height: auto; }
  .hero-facts { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .hero-fact { display: block; }
  .hero-fact dd { text-align: left; margin-block-start: var(--space-xs); }
  .story-copy, .toc { position: static; }
  .info-grid { grid-template-columns: repeat(3, minmax(0, 1fr)); }
  .feature-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .feature:first-child { grid-row: auto; grid-column: span 2; }
  .gallery-item, .gallery-item:nth-child(1), .gallery-item:nth-child(5) { grid-column: span 6; }
  .section-head { grid-template-columns: minmax(0, 1fr); }
}

@media (max-width: 40rem) {
  body { font-size: var(--text-base); }
  .brand span { max-width: 8.5rem; overflow: hidden; text-overflow: ellipsis; }
  .nav-inner > div > .btn { display: none; }
  .nav-shell.is-floating .nav-inner { border-radius: 0; transform: none; }
  .hero { padding-block-start: var(--space-xl); padding-block-end: var(--space-2xl); }
  .hero-media img { object-position: 38% 10%; animation: none; transform: scale(1.02); }
  .hero-logo { width: 12rem; margin-block-end: var(--space-md); }
  .hero h1 { max-width: 11ch; }
  .hero-lede { font-size: var(--text-base); }
  .info-grid, .feature-grid, .fit-grid, .platform-grid, .guide-grid, .edition-grid, .steps, .requirements { grid-template-columns: minmax(0, 1fr); }
  .hero-facts { grid-template-columns: repeat(2, minmax(0, 1fr)); padding: var(--space-md); }
  .hero-fact { padding-block: var(--space-xs); }
  .info-item { border-inline-end: 0; border-block-end: var(--rule-hair) solid var(--color-rule); }
  .feature:first-child { grid-column: auto; }
  .gallery-grid { gap: var(--space-xs); }
  .gallery-item, .gallery-item:nth-child(1), .gallery-item:nth-child(5) { grid-column: span 12; }
  .timeline li { grid-template-columns: minmax(0, 1fr); gap: var(--space-xs); }
  .download-panel { padding: var(--space-xl) var(--space-lg); }
  .download-facts { grid-template-columns: minmax(0, 1fr); }
  .section { padding-block: var(--space-2xl); }
  .final-cta { padding-block: var(--space-3xl); }
  .sticky-cta span { display: none; }
  .sticky-cta .btn { width: 100%; }
  .lightbox-prev { left: var(--space-xs); }
  .lightbox-next, .lightbox-close { right: var(--space-xs); }
  .footer-links { grid-template-columns: minmax(0, 1fr); }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { animation-duration: 150ms !important; animation-iteration-count: 1 !important; transition-duration: 150ms !important; scroll-behavior: auto !important; }
  .hero-media img { transform: scale(1.02) !important; }
}