@font-face { font-family: 'Instrument Serif'; font-style: normal; font-weight: 400; font-display: swap; src: url('/assets/fonts/instrument-serif-normal-400-latin.woff2') format('woff2'); }
@font-face { font-family: 'Instrument Serif'; font-style: italic; font-weight: 400; font-display: swap; src: url('/assets/fonts/instrument-serif-italic-400-latin.woff2') format('woff2'); }
@font-face { font-family: 'Work Sans'; font-style: normal; font-weight: 100 900; font-display: swap; src: url('/assets/fonts/work-sans-normal-variable-latin.woff2') format('woff2'); }
@font-face { font-family: 'Noto Serif SC'; font-style: normal; font-weight: 400; font-display: swap; src: url('/assets/fonts/noto-serif-sc-400-current-copy.woff2') format('woff2'); }

:root {
  color-scheme: light;
  --paper: #faf7f1;
  --paper-raised: #f2eee7;
  --ink: #211d25;
  --muted: #706a70;
  --line: #dfd9d3;
  --brand: #7c5af6;
  --brand-hover: #6849d8;
  --brand-pressed: #5032bc;
  --brand-soft: #f7f4fe;
  --brand-soft-2: #eae5ff;
  --brand-soft-3: #ddd3ff;
  --dark: #201c27;
  --dark-muted: #c6bfce;
  --serif: 'Instrument Serif', 'Noto Serif SC', 'Songti SC', STSong, serif;
  --sans: 'Work Sans', 'PingFang SC', 'Microsoft YaHei', system-ui, sans-serif;
  --mono: 'SFMono-Regular', Consolas, 'Liberation Mono', monospace;
  --header-height: 84px;
  --footer-height: 57px;
  --screen-height: calc(100svh - var(--header-height));
  --content-width: 1120px;
  --page-gutter: clamp(24px, 4vw, 48px);
  --section-title: 44px;
  --section-title-zh: 36px;
  --lead-size: 16px;
  --lead-leading: 26px;
  --copy-size: 15px;
  --copy-leading: 24px;
  --support-size: 13px;
  --support-leading: 20px;
  --link-size: 14px;
  --kicker-size: 11px;
}
@media (min-width: 768px) and (max-width: 1100px) {
  :root { --section-title: 40px; --section-title-zh: 34px; }
}
@media (max-width: 767px) {
  :root { --section-title: 36px; --section-title-zh: 32px; }
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: var(--header-height); scroll-snap-type: y proximity; }
body { margin: 0; background: var(--paper); color: var(--ink); font: 400 16px/1.5 var(--sans); -webkit-font-smoothing: antialiased; }
a { color: inherit; text-underline-offset: .25em; text-decoration-thickness: 1px; }
button { font: inherit; }
button, a, summary { -webkit-tap-highlight-color: transparent; }
:focus-visible { outline: 2px solid var(--brand); outline-offset: 4px; }
::selection { background: var(--brand-soft-3); color: var(--ink); }
[hidden] { display: none !important; }
.container { width: 100%; max-width: var(--content-width); padding-inline: var(--page-gutter); margin-inline: auto; }
.skip-link { position: fixed; left: 12px; top: -100px; z-index: 30; padding: 8px 16px; background: var(--ink); color: var(--paper); }
.skip-link:focus { top: 12px; }
.site-header-shell { position: sticky; top: 0; z-index: 20; background: var(--paper); }
.site-header { display: flex; align-items: center; gap: 24px; padding-block: 20px; min-height: 84px; }
.wordmark { display: inline-flex; align-items: baseline; gap: 6px; text-decoration: none; font: 400 24px/32px var(--serif); white-space: nowrap; }
.wordmark > span { font-family: var(--sans); font-size: 24px; }
.wordmark em { color: var(--brand); font-weight: 400; }
.site-nav { display: flex; align-items: center; gap: 24px; margin-left: auto; font-size: 14px; line-height: 20px; }
.site-nav a { padding-block: 10px; text-decoration: none; white-space: nowrap; }
.site-nav a:hover { text-decoration: underline; }
.header-actions { display: flex; align-items: center; gap: 16px; }
.language-link { display: inline-flex; align-items: center; justify-content: center; min-width: 44px; min-height: 44px; font-size: 13px; text-decoration: none; }
.language-link:hover { color: var(--brand-hover); }
.button { display: inline-flex; align-items: center; justify-content: center; gap: 8px; min-height: 50px; border: 1px solid var(--ink); border-radius: 0; padding: 12px 24px; background: transparent; color: var(--ink); font-size: 16px; font-weight: 500; line-height: 24px; text-decoration: none; transition: background .16s, color .16s, border-color .16s; }
.button:hover { background: var(--paper-raised); text-decoration: none; }
.button-primary { background: var(--brand); border-color: var(--brand); color: #fff; }
.button-primary:hover { background: var(--brand-hover); border-color: var(--brand-hover); }
.button-primary:active { background: var(--brand-pressed); border-color: var(--brand-pressed); }
.button-small { min-height: 36px; padding: 7px 16px; font-size: 14px; line-height: 20px; }
.header-github { background: var(--ink); color: var(--paper); }
.header-github:hover { background: #38313f; }
.arrow-icon { flex: 0 0 auto; width: 15px; height: 15px; }
.menu-toggle { display: none; width: 44px; height: 44px; border: 1px solid var(--line); border-radius: 0; padding: 11px; background: transparent; cursor: pointer; }
.menu-toggle span { display: block; height: 1px; margin: 5px 0; background: var(--ink); }
.eyebrow { margin: 0 0 24px; color: var(--muted); font-size: var(--kicker-size); line-height: 18px; letter-spacing: .14em; text-transform: uppercase; }
.screen { min-block-size: var(--screen-height); scroll-snap-align: start; scroll-snap-stop: always; }
.screen-intro, .screen-start { display: flex; flex-direction: column; }
.screen-intro { justify-content: center; gap: clamp(36px, 5svh, 64px); padding-block: clamp(32px, 4svh, 56px); }
.screen-value { display: grid; grid-template-rows: 1fr 1fr; }
.hero { flex: 0 0 auto; display: grid; grid-template-columns: minmax(0, .95fr) minmax(0, 1.2fr); align-items: center; gap: clamp(32px, 4vw, 64px); }
.hero-intro { min-width: 0; }
.hero .eyebrow { font-size: var(--kicker-size); line-height: 18px; letter-spacing: .14em; margin-bottom: 20px; }
.hero h1 { margin: 0; font: 400 clamp(52px, 4.1vw, 64px)/1.02 var(--serif); letter-spacing: normal; }
.hero h1 > span { display: block; }
.hero h1 em { color: var(--brand); font-weight: 400; }
.hero h1 .ink-emphasis { color: var(--ink); }
:lang(zh-CN) .hero h1 { font-size: clamp(50px, 3.8vw, 60px); line-height: 1.25; letter-spacing: .01em; }
:lang(zh-CN) h1 em, :lang(zh-CN) h2 em { font-style: normal; }
.hero-copy { max-width: 640px; margin: 32px 0 0; color: var(--muted); font-size: var(--lead-size); line-height: var(--lead-leading); }
.hero-actions { display: flex; flex-wrap: wrap; gap: 16px; margin-top: 28px; }
.hero-actions .button { padding-inline: 20px; }
.concept { width: 100%; min-width: 0; margin: 0; justify-self: end; }
.concept-art { position: relative; overflow: hidden; box-shadow: 0 14px 40px -28px rgb(38 27 57 / .28); }
.concept-art { aspect-ratio: 1661 / 947; }
.concept-art img { display: block; width: 100%; height: 100%; object-fit: cover; }
.concept-caption { margin-top: 12px; }
.concept-tabs { display: flex; flex-wrap: wrap; gap: 4px; margin-top: 12px; }
.concept-tabs button > span { margin-right: 5px; font-size: 10px; opacity: .65; }
.concept-tabs button { flex: 1; min-height: 40px; padding: 6px 4px; border: 0; background: transparent; color: var(--muted); font-size: 12px; white-space: nowrap; cursor: pointer; }
.concept-tabs button[aria-selected="true"] { color: var(--brand-pressed); background: var(--brand-soft-2); }
.concept-tabs button:hover { color: var(--brand-hover); }
.concept-perspectives { max-width: 780px; }
.concept-perspective { margin-top: 8px; border-top: 1px solid var(--line); }
.concept-detail summary { display: flex; align-items: center; justify-content: space-between; gap: 16px; min-height: 44px; cursor: pointer; list-style: none; }
.concept-detail summary::-webkit-details-marker { display: none; }
.concept-perspective h3 { margin: 0; font-size: 14px; line-height: 22px; font-weight: 500; }
.concept-detail-toggle { flex: 0 0 auto; color: var(--muted); font-size: 22px; line-height: 24px; transition: transform .16s; }
.concept-detail[open] .concept-detail-toggle { transform: rotate(45deg); }
.concept-perspective p { margin: 0; color: var(--muted); font-size: 14px; line-height: 22px; }
.concept-detail[open] p { padding: 0 28px 12px 0; }
.host-strip { flex: 0 0 auto; }
.host-strip-inner { text-align: center; font-size: 13px; line-height: 20px; }
.host-strip p { margin: 0 0 28px; color: var(--muted); }
.host-names { display: grid; grid-template-columns: repeat(7, minmax(0, 1fr)); align-items: start; gap: 16px; }
.host-logo { display: block; flex: 0 0 auto; width: 36px; height: 36px; object-fit: contain; }
.host-names a { display: flex; flex-direction: column; align-items: center; gap: 10px; min-height: 68px; color: var(--muted); font-size: 12px; line-height: 18px; text-decoration: none; }
.host-names .host-logo, .host-choice .host-logo { filter: grayscale(1); opacity: .65; transition: filter .18s, opacity .18s; }
.host-names a:hover, .host-names a:focus-visible { color: var(--ink); }
.host-names a:hover .host-logo, .host-names a:focus-visible .host-logo, .host-choice:hover .host-logo, .host-choice:focus-visible .host-logo, .host-choice[aria-pressed="true"] .host-logo { filter: none; opacity: 1; }
.section { padding-block: clamp(24px, 4vh, 64px); }
.section h2 { margin: 0; font: 400 clamp(38px, 2.8vw, 60px)/1.12 var(--serif); }
:lang(zh-CN) .section h2 { font-size: clamp(34px, 2.6vw, 52px); line-height: 1.35; }
.screen-value > .section { display: flex; align-items: center; padding-block: 32px; }
.screen-value .section h2 { margin: 0; font: 400 48px/48px var(--serif); }
:lang(zh-CN) .screen-value .section h2 { font-size: 42px; line-height: 1.4; }
.why-grid { display: grid; grid-template-columns: 1fr 1fr; align-items: center; gap: 64px; width: 100%; }
.screen-value #why h2 { line-height: 1.25; }
.why-grid h2 em { color: var(--brand); font-weight: 400; }
.why-grid h2 { text-wrap: balance; }
:lang(zh-CN) .why-grid h2 em { display: block; }
.why-copy p { margin: 0; color: var(--muted); font-size: var(--lead-size); line-height: var(--lead-leading); }
.why-copy p + p { margin-top: 20px; }
.why-copy p:last-of-type { color: var(--ink); font-weight: 500; }
.capabilities { background: var(--dark); color: var(--paper); }
.screen-start { min-block-size: 0; }
.screen-start > #quick-start { flex: 0 0 auto; display: block; padding-block: 64px; }
.screen-start #quick-start > .eyebrow { margin-bottom: 12px; }
.screen-start #start-title { margin: 0; font: 400 var(--section-title)/1.12 var(--serif); }
:lang(zh-CN) .screen-start #start-title { font-size: var(--section-title-zh); line-height: 1.35; }
.start-steps { display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); gap: 24px; padding: 0; margin: 48px 0 0; list-style: none; }
.start-step { min-width: 0; border-top: 2px solid var(--ink); padding-top: 20px; }
.start-number { display: block; color: var(--brand); font: 400 36px/40px var(--serif); }
.start-step h3 { margin: 8px 0 0; font-size: 16px; font-weight: 600; line-height: 24px; }
.start-step-body { margin-top: 12px; }
.start-step p { margin: 0; color: var(--muted); font-size: 14px; line-height: 22px; }
.start-step .prompt-sample { margin-top: 12px; padding: 12px; background: var(--paper-raised); font: 12px/18px var(--mono); overflow-wrap: anywhere; }
.host-guides { margin-top: 48px; scroll-margin-block-start: 24px; }
.host-guides-heading { display: flex; align-items: center; flex-wrap: wrap; gap: 8px 20px; margin-bottom: 20px; }
.host-guides-heading h3 { margin: 0; font-size: 20px; font-weight: 500; line-height: 28px; }
.host-faq-link { display: inline-flex; flex: 0 0 auto; align-items: center; gap: 6px; min-height: 32px; color: var(--brand-hover); font-size: 14px; }
.host-faq-link:hover { color: var(--brand-hover); }
.host-picker[data-enhanced] { display: grid; grid-template-columns: minmax(0, .85fr) minmax(0, 1.15fr); align-items: start; gap: 32px; }
.host-selector { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 12px; }
.host-choice { position: relative; display: flex; align-items: center; gap: 14px; min-width: 0; min-height: 100px; padding: 18px; border: 1px solid var(--line); background: transparent; color: var(--muted); text-align: left; cursor: pointer; transition: border-color .18s, background .18s, color .18s; }
.host-choice:first-child { grid-column: 1 / -1; min-height: 88px; }
.host-choice > span { font-size: 13px; line-height: 20px; }
.host-choice small { display: block; margin-top: 2px; font-size: 11px; font-weight: 400; }
.host-choice .host-choice-check { position: absolute; right: 10px; top: 8px; color: var(--brand); visibility: hidden; }
.host-choice:hover { border-color: var(--brand-soft-3); background: var(--paper-raised); color: var(--ink); }
.host-choice[aria-pressed="true"] { border-color: var(--brand); background: var(--brand-soft); color: var(--ink); }
.host-choice[aria-pressed="true"] .host-choice-check { visibility: visible; }
.host-panels { display: grid; gap: 24px; min-width: 0; }
.host-picker[data-enhanced] .host-panels { gap: 0; }
.host-picker[data-enhanced] .host-install-card { grid-area: 1 / 1; }
.host-install-card.is-inactive { visibility: hidden; pointer-events: none; }
.host-install-card { display: flex; flex-direction: column; min-width: 0; padding: 28px; border: 1px solid var(--line); background: var(--paper); }
.host-install-heading { display: flex; align-items: center; gap: 14px; min-height: 48px; }
.host-install-heading h4 { margin: 0; font-size: 16px; font-weight: 600; line-height: 24px; }
.host-install-heading small { display: block; margin-top: 4px; color: var(--muted); font-size: 12px; line-height: 20px; }
.host-prompt-lead { margin: 12px 0 0; color: var(--muted); font-size: 14px; line-height: 22px; }
.host-prompt { margin: 20px 0 24px; padding: 20px; max-height: 280px; overflow: auto; background: var(--paper-raised); white-space: pre-wrap; overflow-wrap: anywhere; font: 13px/22px var(--mono); }
.host-install-actions { display: flex; align-items: center; justify-content: space-between; gap: 12px; flex-wrap: wrap; margin-top: auto; }
.host-install-actions .button { cursor: pointer; }
.host-install-actions > a { display: inline-flex; align-items: center; gap: 6px; color: var(--muted); font-size: var(--link-size); line-height: 20px; }
.host-install-actions > a:hover { color: var(--brand-hover); }
.host-copy-status { min-height: 20px; margin: 12px 0 0; color: var(--brand-hover); font-size: 12px; line-height: 20px; }
.closing { flex: 0 0 auto; padding-block: 0 80px; }
.closing-inner { padding: 64px; border: 1px solid var(--brand-soft-3); background: var(--brand-soft); }
.closing h2 { margin: 0; font: 400 44px/1.16 var(--serif); }
.closing h2 em { color: var(--brand); font-weight: 400; }
:lang(zh-CN) .closing h2 { font-size: 40px; line-height: 1.35; }
.closing .button { margin-top: 32px; }
.site-footer { border-top: 1px solid var(--line); padding-block: 12px; color: var(--muted); font-size: 13px; line-height: 20px; }
.footer-inner { display: flex; justify-content: space-between; align-items: center; gap: 12px; }
.footer-links { display: flex; justify-content: center; flex-wrap: wrap; gap: 24px; }
.footer-links a { display: inline-flex; align-items: center; min-height: 32px; text-decoration: none; }
.footer-links a:hover { text-decoration: underline; }
.site-footer { scroll-snap-align: end; }
.scroll-cue { position: fixed; z-index: 25; left: 50%; bottom: 16px; display: grid; place-items: center; width: 44px; height: 44px; padding: 0; transform: translateX(-50%); border: 0; background: transparent; color: var(--muted); cursor: pointer; }
.scroll-cue.is-on-dark { color: var(--paper); }
.scroll-cue.is-obstructed { visibility: hidden; pointer-events: none; }
.scroll-cue:hover { color: var(--brand); }
.scroll-cue svg { animation: scroll-hint 2.4s ease-in-out infinite; }
.scroll-cue:hover svg, .scroll-cue:focus-visible svg { animation-play-state: paused; }
@keyframes scroll-hint { 0%, 100% { transform: translateY(-2px); opacity: .55; } 50% { transform: translateY(3px); opacity: .95; } }
@media (min-width: 1024px) and (min-height: 700px) {
  html { scroll-snap-type: y mandatory; }
}
@media (min-width: 1024px) and (max-width: 1151px) {
  .hero { gap: 32px; }
  .hero h1 { font-size: 52px; }
  :lang(zh-CN) .hero h1 { font-size: 50px; }
  .hero .eyebrow { letter-spacing: .1em; }
}
@media (min-width: 1024px) and (max-height: 800px) {
  :root { --header-height: 64px; }
  .site-header { min-height: var(--header-height); padding-block: 10px; }
  .screen-intro { gap: 24px; padding-block: 8px 36px; }
  .hero { grid-template-columns: minmax(0, 1.05fr) minmax(0, 1fr); gap: 40px; }
  .hero .eyebrow { margin-bottom: 12px; font-size: var(--kicker-size); line-height: 18px; }
  .hero h1 { font-size: 48px; }
  :lang(zh-CN) .hero h1 { font-size: 44px; }
  .hero-copy { margin-top: 24px; }
  .hero-actions { margin-top: 20px; }
  .hero-actions .button { min-height: 44px; padding-block: 9px; font-size: 14px; }
  .host-strip-inner { font-size: 12px; line-height: 18px; }
  .host-strip p { margin-bottom: 24px; }
  .host-names a { gap: 8px; min-height: 58px; font-size: 11px; line-height: 18px; }
  .host-names .host-logo { width: 32px; height: 32px; }
  .scroll-cue { width: 32px; height: 32px; bottom: 4px; }
}
@media (max-width: 1023px) {
  .hero { grid-template-columns: 1fr; gap: 32px; }
  .hero-intro { max-width: 720px; }
  .concept { max-width: 800px; justify-self: start; }
  .screen-start > #quick-start { flex-grow: 0; }
  .start-steps { grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 32px 24px; }
  .host-picker[data-enhanced] { grid-template-columns: minmax(0, .8fr) minmax(0, 1.2fr); gap: 24px; }
  .host-choice { flex-direction: column; align-items: flex-start; gap: 10px; padding: 16px; }
  .host-choice:first-child { flex-direction: row; align-items: center; }
  .host-names { grid-template-columns: repeat(4, minmax(0, 1fr)); gap: 24px 16px; }
}
@media (max-width: 767px) {
  .site-header { gap: 16px; }
  .site-nav { gap: 16px; font-size: 12px; }
  .header-actions { gap: 8px; }
  .hero h1 { font-size: clamp(36px, 11.9vw, 60px); }
  :lang(zh-CN) .hero h1 { font-size: clamp(36px, 11.2vw, 48px); }
  .hero-copy { margin-top: 28px; }
  .hero-actions { margin-top: 24px; }
  .screen-value { display: block; }
  .screen-value > .section { padding-block: 56px; }
  .why-grid { grid-template-columns: 1fr; gap: 28px; }
  .start-step p { max-width: 520px; font-size: 15px; line-height: 24px; }
  .start-steps { grid-template-columns: 1fr; }
  .host-picker[data-enhanced] { grid-template-columns: 1fr; gap: 24px; }
  .host-selector { grid-template-columns: repeat(3, minmax(0, 1fr)); }
  .host-choice, .host-choice:first-child { flex-direction: column; align-items: center; justify-content: center; min-height: 104px; text-align: center; }
  .host-choice:first-child { grid-column: auto; }
  .host-install-card { padding: 24px; }
  .closing-inner { padding: 48px; }
  .closing h2 { font-size: 36px; }
  :lang(zh-CN) .closing h2 { font-size: 32px; }
}
@media (max-width: 639px) {
  .scroll-cue { bottom: 12px; }
  .site-header { flex-wrap: wrap; gap: 8px; padding-block: 16px; }
  .header-actions { margin-left: auto; }
  .header-github { display: none; }
  .menu-toggle { display: block; }
  .site-nav { display: none; flex-basis: 100%; order: 3; margin: 0; padding-top: 8px; font-size: 14px; }
  .site-nav.is-open { display: flex; flex-wrap: wrap; }
  .site-nav a { min-height: 44px; }
  .hero .eyebrow { font-size: var(--kicker-size); letter-spacing: .14em; }
  .hero-actions { gap: 12px; }
  .hero-actions .button { padding-inline: 18px; font-size: 14px; }
  .section { padding-block: 40px; }
  .section h2 { font-size: 44px; }
  :lang(zh-CN) .section h2 { font-size: 36px; }
  .screen-start > #quick-start { padding-block: 64px; }
  .closing { padding-bottom: 64px; }
  .closing-inner { padding: 48px 24px; }
  .footer-links a { min-height: 44px; }
  .footer-inner { flex-direction: column; text-align: center; }
  .host-names { grid-template-columns: repeat(3, minmax(0, 1fr)); }
  .host-choice { padding: 14px 8px; }
  .host-choice > span { font-size: 11px; line-height: 16px; }
  .host-choice .host-logo { width: 28px; height: 28px; }
  .host-prompt { padding: 16px; font-size: 12px; line-height: 20px; }
  .host-install-card { padding: 20px; }
  .screen-value .section h2 { font-size: 40px; line-height: 1.2; }
  :lang(zh-CN) .screen-value .section h2 { font-size: 34px; line-height: 1.4; }
}
@media (max-width: 359px) {
  .concept-tabs button { font-size: 11px; }
}
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; scroll-snap-type: y proximity; }
  .scroll-cue svg { animation: none; }
  *, *::before, *::after { transition: none !important; }
}

/* Narrative expansion: retain the shared measure, typography and paper/ink palette. */
.site-nav a[aria-current="page"] { color: var(--brand-hover); }
.screen-pain { display: flex; align-items: center; padding-block: 48px; }
.screen-pain .eyebrow { margin-bottom: 24px; }
.screen-pain .why-grid { gap: 48px; }
.screen-pain .why-grid h2 { font-size: 48px; line-height: 1.15; }
:lang(zh-CN) .screen-pain .why-grid h2 { font-size: 42px; line-height: 1.4; }
.screen-pain .why-grid h2 em { display: block; }
.scenario-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 48px; margin-top: 40px; }
.scenario { border-top: 1px solid var(--line); padding-top: 20px; }
.scenario h3 { margin: 0; font-size: 17px; line-height: 24px; font-weight: 500; }
.scenario-number { margin-right: 12px; color: var(--brand); font: italic 24px/24px var(--serif); }
.scenario p { margin: 16px 0 0; font-size: 15px; line-height: 23px; }
.scenario p > span { display: block; margin-bottom: 4px; font-size: 11px; line-height: 18px; color: var(--muted); }
.scenario-result { color: var(--muted); }
.scenario-intent { border-left: 2px solid var(--brand); padding-left: 14px; }
.screen-capabilities { display: flex; align-items: center; padding-block: 48px; }
.capability-heading { display: grid; grid-template-columns: 1fr 1fr; align-items: start; gap: 48px; }
.capability-eyebrow { color: var(--dark-muted); margin-bottom: 12px; }
.capability-heading h2 { font-size: var(--section-title); }
.capability-heading h2 em { display: block; color: #b8a1ff; font-weight: 400; }
:lang(zh-CN) .capability-heading h2 { font-size: var(--section-title-zh); line-height: 1.35; }
.capability-lead { margin: 0; color: var(--dark-muted); font-size: var(--lead-size); line-height: var(--lead-leading); }
.kit-links { display: flex; gap: 12px 24px; flex-wrap: wrap; margin-top: 16px; }
.kit-links a { display: inline-flex; align-items: center; gap: 6px; min-height: 32px; color: #d5c6ff; font-size: var(--link-size); }
.kit-links a:hover { color: white; }
.start-paths { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 32px; margin-top: 32px; }
.start-path { display: flex; flex-direction: column; align-items: start; border-top: 2px solid var(--ink); padding-top: 16px; }
.start-path h3 { margin: 0; font-size: 18px; font-weight: 500; line-height: 26px; }
.start-path p { margin: 10px 0 12px; color: var(--muted); font-size: var(--copy-size); line-height: var(--copy-leading); }
.start-path a { display: inline-flex; align-items: center; gap: 8px; margin-top: auto; min-height: 32px; font-size: var(--link-size); }
.start-path a:hover, .text-link:hover { color: var(--brand-hover); }
.text-link { display: inline-flex; align-items: center; gap: 6px; min-height: 32px; }
.faq-body { scroll-snap-type: none; }
html:has(.faq-body) { scroll-snap-type: none; }
.faq-page { padding-block: 40px 80px; }
.faq-back { color: var(--muted); font-size: var(--link-size); }
.faq-heading { padding-block: 40px; }
.faq-heading .eyebrow { margin-bottom: 20px; }
.faq-heading h1 { max-width: 840px; margin: 0; font: 400 56px/1.1 var(--serif); }
:lang(zh-CN) .faq-heading h1 { font-size: 42px; line-height: 1.4; }
.faq-heading > p:last-child { margin: 20px 0 0; color: var(--muted); max-width: 720px; font-size: 16px; line-height: 26px; }
.faq-list { max-width: 840px; border-top: 1px solid var(--line); }
.faq-item { border-bottom: 1px solid var(--line); scroll-margin-top: 24px; }
.faq-item summary { display: flex; justify-content: space-between; align-items: center; gap: 24px; padding-block: 24px; cursor: pointer; list-style: none; }
.faq-item summary::-webkit-details-marker { display: none; }
.faq-item h2 { margin: 0; font-size: 18px; line-height: 28px; font-weight: 500; }
.faq-toggle-icon { position: relative; flex: 0 0 14px; height: 14px; color: var(--brand); }
.faq-toggle-icon::before, .faq-toggle-icon::after { content: ''; position: absolute; background: currentColor; }
.faq-toggle-icon::before { width: 14px; height: 1px; top: 6px; left: 0; }
.faq-toggle-icon::after { width: 1px; height: 14px; top: 0; left: 6px; transition: transform .25s ease; }
.faq-item[open] .faq-toggle-icon::after { transform: scaleY(0); }
.faq-answer { max-width: 740px; padding: 0 32px 24px 0; }
.faq-answer p { color: var(--muted); margin: 0 0 14px; font-size: var(--copy-size); line-height: 26px; }
.faq-answer a { font-size: var(--link-size); }
.faq-end { display: flex; flex-wrap: wrap; align-items: center; gap: 24px; margin-top: 40px; }
@media (min-width: 1024px) and (max-height: 800px) {
  .screen-pain { padding-block: 32px 40px; }
  .screen-pain .eyebrow { margin-bottom: 16px; }
  .scenario-grid { margin-top: 28px; }
  .screen-pain .why-grid h2 { font-size: 44px; }
  :lang(zh-CN) .screen-pain .why-grid h2 { font-size: 38px; }
}
@media (max-width: 1023px) {
  .site-nav { gap: 16px; }
  .capability-heading { gap: 32px; }
}
@media (max-width: 767px) {
  .screen-pain, .screen-capabilities { padding-block: 48px; }
  .screen-pain .why-grid, .capability-heading { grid-template-columns: 1fr; gap: 24px; }
  .scenario-grid { grid-template-columns: 1fr; gap: 28px; margin-top: 32px; }
  .screen-pain .why-grid h2 { font-size: 44px; }
  :lang(zh-CN) .screen-pain .why-grid h2 { font-size: 34px; }
  .start-paths { grid-template-columns: 1fr; gap: 28px; margin-top: 32px; }
  .screen-start > #quick-start { padding-block: 48px; }
  .host-guides-heading { gap: 8px 16px; }
  .start-path p { margin-bottom: 10px; }
  .faq-page { padding-top: 24px; padding-bottom: 48px; }
  .faq-heading h1 { font-size: 44px; }
  :lang(zh-CN) .faq-heading h1 { font-size: 34px; }
  .faq-item h2 { font-size: 16px; line-height: 26px; }
  .faq-answer { padding-right: 0; }
}
@media (max-width: 359px) {
  .concept-tabs button { font-size: 10px; }
  .concept-tabs button > span { display: none; }
}

/* Clearer mechanism overview, concrete scenarios and visible Kit extension. */
.screen-intro { justify-content: flex-start; gap: clamp(24px, 4svh, 40px); padding-block: clamp(24px, 4.5svh, 54px) 48px; }
.hero { align-items: start; }
.concept-system { position: relative; }
.concept-system > img { display: block; width: 100%; height: auto; }
.system-label { position: absolute; transform: translateX(-50%); color: #52465f; font-size: 12px; line-height: 18px; white-space: nowrap; }
.system-agent { left: 28%; top: 81%; }
.system-panel { left: 65%; top: 27%; }
.system-loop { left: 43%; top: 9%; color: var(--brand-hover); }
.system-results { left: 88%; top: 86%; }
.screen-pain { padding-block: 40px; }
.screen-pain .why-grid { align-items: center; gap: 40px; }
.screen-pain .why-grid h2 { width: fit-content; max-width: 100%; font-size: clamp(24px, 3.4vw, 43px); line-height: 1.08; text-wrap: initial; }
.why-title-main { display: block; }
:lang(en) .why-title-main { white-space: nowrap; }
/* Wrap complete thought groups within the heading's existing column. */
:lang(en) .why-grid h2 em { display: flex; flex-wrap: wrap; align-items: baseline; gap: .12em .24em; margin-top: 10px; font-size: .73em; line-height: 1.2; }
:lang(en) .why-title-phrase { white-space: nowrap; }
.why-title-lead, .why-title-join { font-family: var(--sans); font-size: .6em; font-style: normal; color: var(--muted); }
:lang(zh-CN) .why-title-lead { margin-right: .4em; white-space: nowrap; }
:lang(zh-CN) .screen-pain .why-grid h2 { font-size: 36px; line-height: 1.4; text-wrap: balance; }
:lang(zh-CN) .why-title-main { word-break: keep-all; }
.why-copy p:last-of-type { color: var(--muted); font-weight: 400; }
.case-carousel { margin-top: 52px; }
.case-carousel[data-enhanced] .case-slides { display: grid; }
.case-carousel[data-enhanced] .case-slide { grid-area: 1 / 1; }
.case-carousel[data-enhanced] .case-slide.is-inactive { visibility: hidden; pointer-events: none; }
.case-slide { display: grid; grid-template-columns: .8fr 1.2fr; gap: 16px 40px; align-items: center; }
.case-slide + .case-slide { margin-top: 32px; }
.case-carousel[data-enhanced] .case-slide { margin-top: 0; min-height: 330px; }
.case-copy .eyebrow { margin-bottom: 14px; }
.case-copy h3 { font: 400 34px/1.15 var(--serif); margin: 0; text-wrap: balance; }
:lang(zh-CN) .case-copy h3 { font-size: 28px; line-height: 1.5; }
.case-description { margin: 18px 0 0; font-size: var(--copy-size); line-height: var(--copy-leading); color: var(--muted); max-width: 540px; }
.case-description + .case-description { margin-top: 12px; }
.case-visual { position: relative; width: 100%; max-width: 520px; justify-self: end; margin: 0; }
.case-visual img { display: block; width: 100%; height: auto; }
.case-image-label { position: absolute; transform: translateX(-50%); font-size: 11px; line-height: 18px; color: #52465f; background: var(--paper); padding: 0 5px; white-space: nowrap; }
.case-image-label.label-0 { left: 20%; top: -2%; }
.case-image-label.label-1 { left: 15%; top: 27%; }
.case-image-label.label-2 { left: 79%; top: -2%; }
.case-image-label.label-3 { left: 84%; top: 26%; }
.case-image-label.label-4 { left: 50%; top: 16%; }
.case-slide-note { grid-column: 1 / -1; font-size: 10px; line-height: 18px; color: var(--muted); margin: 0; }
.case-slide-text { grid-template-columns: 1fr; align-content: center; text-align: center; }
.case-slide-text .case-copy { max-width: 650px; margin: 0 auto; }
.case-slide-text .case-description { margin-inline: auto; }
.case-slide-text .case-slide-note { margin-top: 16px; font-size: 13px; line-height: 22px; }
.case-more-list { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 36px; margin: 24px 0 0; text-align: left; }
.case-more-list dt { font-size: 15px; font-weight: 500; }
.case-more-list dd { margin: 10px 0 0; color: var(--muted); font-size: var(--copy-size); line-height: var(--copy-leading); }
.case-switch { display: flex; align-items: center; justify-content: center; gap: 10px; width: 160px; min-height: 44px; margin: 28px auto 0; padding: 10px 16px; border: 1px solid var(--line); border-radius: 0; background: transparent; color: var(--brand-pressed); font-size: 14px; cursor: pointer; scroll-margin-block: 100px; }
.case-switch:hover { border-color: var(--brand); background: var(--brand-soft); }
.case-switch svg { flex: 0 0 auto; transform: rotate(var(--case-turn, 0deg)); transition: transform .32s cubic-bezier(.22,.7,.2,1); }
/* Leave a separate landing area for the fixed next-section arrow. */
.screen-pain { padding-bottom: 104px; }
@media (prefers-reduced-motion: reduce) {
  .case-switch svg { transition: none; }
}
@media (max-width: 767px) {
  .case-slide { grid-template-columns: 1fr; gap: 20px; }
  .case-carousel[data-enhanced] .case-slide { min-height: 475px; align-content: center; }
  .case-copy h3 { font-size: 30px; }
  :lang(zh-CN) .case-copy h3 { font-size: 25px; }
  .case-description { margin-top: 12px; }
  .case-visual { max-width: 440px; justify-self: center; }
  .case-carousel { margin-top: 40px; }
  .case-more-list { grid-template-columns: 1fr; gap: 22px; margin-top: 16px; }
  .case-more-list dd { margin-top: 6px; }
  .case-image-label { font-size: 10px; line-height: 16px; padding-inline: 3px; }
}
/* One mechanism at a time, with the four capabilities always visible. */
.capability-explorer { position: relative; margin-top: 32px; }
.capability-item + .capability-item { margin-top: 32px; }
.capability-fallback-title { font-size: 18px; font-weight: 500; }
.capability-explorer[data-enhanced] { display: grid; grid-template-columns: minmax(0, .9fr) minmax(0, 1.4fr); grid-template-rows: repeat(4, auto); column-gap: 40px; }
.capability-explorer[data-enhanced] .capability-item { display: contents; }
.capability-explorer[data-enhanced] .capability-fallback-title { display: none; }
.capability-copy { grid-column: 1; grid-row: var(--cap-row); border-left: 2px solid #514955; transition: border-color .38s; }
.capability-copy.is-active { border-color: #b8a1ff; background: linear-gradient(90deg, #b8a1ff14, #b8a1ff00); }
.capability-toggle { width: 100%; position: relative; text-align: left; border: 0; padding: 14px 28px 14px 20px; background: transparent; color: var(--paper); cursor: pointer; transition: color .2s, background .2s; }
.capability-toggle:hover { background-color: #ffffff07; }
.capability-name { display: block; font-size: 19px; font-weight: 500; line-height: 26px; }
:lang(zh-CN) .capability-name { font-size: 17px; }
.capability-hint { display: block; margin-top: 5px; color: var(--dark-muted); font-size: var(--support-size); line-height: var(--support-leading); }
.capability-pointer { position: absolute; right: 14px; top: 22px; width: 12px; height: 12px; font-size: 0; color: #b8a1ff; opacity: .65; transition: opacity .38s; }
.capability-pointer::before, .capability-pointer::after { content: ''; position: absolute; background: currentColor; }
.capability-pointer::before { width: 12px; height: 1px; top: 5px; left: 0; }
.capability-pointer::after { width: 1px; height: 12px; top: 0; left: 5px; transform: scaleY(1); transition: transform .38s cubic-bezier(.22,.7,.2,1); }
.capability-toggle[aria-expanded="true"] .capability-name { color: #d3c3ff; }
.capability-toggle[aria-expanded="true"] .capability-pointer { opacity: 1; }
.capability-toggle[aria-expanded="true"] .capability-pointer::after { transform: scaleY(0); }
.capability-detail { display: grid; grid-template-rows: 1fr; }
.capability-explorer[data-enhanced] .capability-detail { grid-template-rows: 0fr; opacity: 0; transition: grid-template-rows .42s cubic-bezier(.22,.7,.2,1), opacity .26s ease; }
.capability-explorer[data-enhanced] .capability-copy.is-active .capability-detail { grid-template-rows: 1fr; opacity: 1; }
.capability-detail > div { min-height: 0; overflow: hidden; }
.capability-panel { min-width: 0; }
.capability-explorer[data-enhanced] .capability-panel { grid-column: 2; grid-row: 1 / span 4; align-self: center; opacity: 1; transform: translateY(0); visibility: visible; transition: opacity .38s ease, transform .42s cubic-bezier(.22,.7,.2,1), visibility 0s; }
.capability-explorer[data-enhanced] .capability-panel.is-inactive { opacity: 0; transform: translateY(7px); visibility: hidden; pointer-events: none; transition: opacity .3s ease, transform .42s cubic-bezier(.22,.7,.2,1), visibility 0s .3s; }
.capability-art { aspect-ratio: 4 / 3; margin: 0; overflow: hidden; background: #faf7f1; }
.capability-image-button { position: relative; display: block; width: 100%; height: 100%; border: 0; padding: 0; background: transparent; color: var(--ink); cursor: zoom-in; }
.capability-image-button:disabled { cursor: default; }
.capability-art:has(.capability-image-button:focus-visible) { outline: 2px solid #b8a1ff; outline-offset: 4px; }
.capability-image-button img { display: block; width: 100%; height: 100%; object-fit: contain; }
.capability-zoom-label { position: absolute; top: 10px; right: 10px; padding: 5px 9px; background: #faf7f1ee; font-size: 11px; opacity: 0; transition: opacity .2s; }
.capability-image-button:hover .capability-zoom-label, .capability-image-button:focus-visible .capability-zoom-label { opacity: 1; }
.capability-zoom-dialog { width: min(1180px, calc(100vw - 40px)); max-width: none; max-height: calc(100svh - 40px); padding: 0; border: 1px solid #514955; background: var(--paper); color: var(--ink); }
.capability-zoom-dialog::backdrop { background: #15121cdb; backdrop-filter: blur(5px); }
.capability-zoom-header { position: sticky; top: 0; display: flex; align-items: center; justify-content: space-between; padding: 8px 20px; background: var(--paper); }
.capability-zoom-header h3 { font: 500 16px/24px var(--sans); margin: 0; }
.capability-zoom-header button { width: 40px; height: 40px; border: 0; padding: 0; background: transparent; color: var(--ink); font-size: 28px; cursor: pointer; }
.capability-zoom-dialog > img { display: block; width: 100%; max-height: calc(100svh - 100px); object-fit: contain; }
@media (hover: none) { .capability-zoom-label { opacity: 1; } }
.capability-explanation { margin: 0; padding: 0 24px 20px 20px; color: var(--dark-muted); font-size: 14px; line-height: var(--copy-leading); }
.kit-invitation { display: flex; align-items: center; justify-content: space-between; gap: 24px; border-top: 1px solid #514955; margin-top: 32px; padding-top: 24px; }
.kit-invitation h3 { font: 400 29px/1.2 var(--serif); margin: 0; }
:lang(zh-CN) .kit-invitation h3 { font-size: 24px; line-height: 1.4; }
.kit-invitation p { color: var(--dark-muted); margin: 8px 0 0; font-size: var(--support-size); line-height: var(--support-leading); }
.kit-invitation .kit-example { margin-top: 4px; font-size: 12px; }
.kit-invitation .kit-links { margin: 0; flex-shrink: 0; gap: 12px 22px; }
@media (max-width: 1023px) and (min-width: 768px) {
  .capability-explorer[data-enhanced] { grid-template-columns: minmax(260px, .95fr) minmax(0, 1.2fr); column-gap: 28px; }
  .capability-name { font-size: 18px; }
  .kit-invitation { align-items: start; }
  .kit-invitation .kit-links { flex-direction: column; gap: 2px; }
}
@media (max-width: 767px) {
  .capability-explorer[data-enhanced] { display: block; margin-top: 28px; }
  .capability-explorer[data-enhanced] .capability-item { display: block; margin: 0; border-bottom: 1px solid #514955; }
  .capability-toggle { width: 100%; padding-block: 16px; }
  .capability-explorer[data-enhanced] .capability-panel { padding: 12px 0 24px; }
  .capability-explorer[data-enhanced] .capability-panel.is-inactive { display: none; }
  .capability-art { aspect-ratio: 4 / 3; }
  .kit-invitation { display: block; margin-top: 28px; padding-top: 24px; }
  .kit-invitation .kit-links { margin-top: 14px; }
  .kit-invitation h3 { font-size: 27px; }
}
.kit-links { margin-top: 10px; }
@media (min-width: 900px) {
  /* Share extra viewport height between the chapter's outer and internal space. */
  .screen-intro { justify-content: center; gap: clamp(20px, calc(20svh - 92px), 100px); padding-block: clamp(16px, 3svh, 32px) clamp(32px, 5svh, 56px); }
  .hero { grid-template-columns: minmax(0, .9fr) minmax(0, 1.1fr); gap: 40px; }
  .hero-copy { max-width: 420px; }
  :lang(zh-CN) .hero-copy { max-width: 400px; }
  .concept { max-width: min(100%, 90svh); }
  .hero h1 { font-size: clamp(50px, 4.4vw, 62px); }
  :lang(zh-CN) .hero h1 { font-size: clamp(46px, 3.9vw, 56px); }
  .host-names { grid-template-columns: repeat(7, minmax(0, 1fr)); gap: 14px; }
}
@media (min-width: 900px) and (max-height: 800px) {
  :root { --header-height: 64px; }
  .site-header { min-height: 64px; padding-block: 10px; }
  .screen-intro { padding-block: 16px 32px; }
  .hero .eyebrow { margin-bottom: 12px; font-size: var(--kicker-size); line-height: 18px; }
  .hero h1 { font-size: 52px; }
  :lang(zh-CN) .hero h1 { font-size: 48px; }
  .hero-copy { margin-top: 24px; }
  .hero-actions { margin-top: 20px; }
  .hero-actions .button { min-height: 44px; padding: 9px 16px; font-size: 14px; }
  .host-strip p { margin-bottom: 20px; }
  .host-strip-inner { font-size: 12px; line-height: 18px; }
  .host-names a { gap: 8px; min-height: 58px; font-size: 11px; line-height: 18px; }
  .host-names .host-logo { width: 30px; height: 30px; }
}
@media (min-width: 900px) and (max-width: 1100px) {
  .hero { gap: 28px; }
  .hero h1 { font-size: 48px; }
  :lang(zh-CN) .hero h1 { font-size: 44px; }
  .system-label { font-size: 10px; }
}
@media (max-width: 899px) {
  .screen-intro { gap: 32px; padding-top: 24px; }
  .hero { grid-template-columns: 1fr; }
  .concept-system { max-width: 680px; justify-self: center; }
}
@media (max-width: 767px) {
  .screen-pain .why-grid h2 { font-size: clamp(24px, 7.5vw, 43px); }
  :lang(zh-CN) .screen-pain .why-grid h2 { font-size: 32px; }
  :lang(zh-CN) .why-title-main { word-break: normal; }
  .system-label { font-size: 10px; line-height: 14px; }
}