@font-face {
  font-family: "EngRSI Serif";
  src: url("../fonts/serif-sc.woff2") format("woff2");
  font-weight: 400;
  font-display: swap;
}

:root {
  --ink: #0c0d0f;
  --deep: #070809;
  --paper: #f3f0e9;
  --paper-2: #e6e1d6;
  --on-ink: #ede9e1;
  --on-ink-2: #a3a29c;
  --on-paper: #17181a;
  --on-paper-2: #57564f;
  --accent: #e8692b;
  --accent-text: #a93f0d;
  --line-ink: rgba(237, 233, 225, .14);
  --line-paper: rgba(23, 24, 26, .16);
  --serif: "EngRSI Serif", "Songti SC", "Noto Serif CJK SC", "Source Han Serif SC", serif;
  --sans: -apple-system, BlinkMacSystemFont, "PingFang SC", "Microsoft YaHei", "Noto Sans CJK SC", "Helvetica Neue", Arial, sans-serif;
  --mono: ui-monospace, "SF Mono", Menlo, Consolas, monospace;
  --gutter: clamp(20px, 5vw, 72px);
  --sec: clamp(88px, 13vw, 184px);
  --head-h: 68px;
}

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

html { scroll-behavior: smooth; scroll-padding-top: var(--head-h); -webkit-text-size-adjust: 100%; }

body {
  margin: 0;
  background: var(--ink);
  color: var(--on-ink);
  font-family: var(--sans);
  font-size: 17px;
  line-height: 1.8;
  -webkit-font-smoothing: antialiased;
}

img { display: block; max-width: 100%; height: auto; }
a { color: inherit; }
h1, h2, h3, p, ul, ol, dl, dd, figure { margin: 0; padding: 0; }
ul, ol { list-style: none; }
address { font-style: normal; }
:focus-visible { outline: 2px solid var(--accent); outline-offset: 3px; }

.vh { position: absolute; width: 1px; height: 1px; overflow: hidden; clip-path: inset(50%); white-space: nowrap; }

.skip {
  position: fixed; left: 12px; top: -60px; z-index: 100;
  padding: 8px 14px; background: var(--paper); color: var(--on-paper);
}
.skip:focus { top: 12px; }

.wrap { max-width: 1400px; margin: 0 auto; padding: 0 var(--gutter); }

/* 顶栏 */
.top {
  position: fixed; inset: 0 0 auto 0; z-index: 50;
  transition: background .3s, border-color .3s;
  border-bottom: 1px solid transparent;
}
.top.is-stuck {
  background: rgba(12, 13, 15, .86);
  -webkit-backdrop-filter: blur(14px); backdrop-filter: blur(14px);
  border-bottom-color: var(--line-ink);
}
.top__in {
  max-width: 1400px; height: var(--head-h); margin: 0 auto; padding: 0 var(--gutter);
  display: flex; align-items: center; justify-content: space-between; gap: 24px;
}
.brand { display: inline-flex; align-items: center; gap: 10px; text-decoration: none; font-weight: 600; font-size: 19px; letter-spacing: .01em; }
.brand__mark { width: 26px; height: 26px; }
.nav { display: flex; align-items: center; gap: clamp(18px, 2.4vw, 34px); font-size: 15px; }
.nav a { text-decoration: none; color: var(--on-ink-2); transition: color .2s; }
.nav a:hover, .nav a.is-here { color: var(--on-ink); }
.nav .nav__cta { color: var(--on-ink); border: 1px solid var(--line-ink); padding: 6px 16px; }
.nav .nav__cta:hover { border-color: var(--accent); }
.menu-btn { display: none; background: none; border: 1px solid var(--line-ink); color: var(--on-ink); padding: 6px 14px; font: inherit; font-size: 15px; cursor: pointer; }

/* 首屏 */
.hero { position: relative; min-height: 100vh; min-height: 100svh; display: flex; align-items: flex-end; overflow: hidden; background: var(--deep); }
.hero__canvas { position: absolute; inset: 0; width: 100%; height: 100%; }
.hero::after {
  content: ""; position: absolute; inset: auto 0 0 0; height: 58%; pointer-events: none;
  background: linear-gradient(to top, rgba(7, 8, 9, .92) 18%, rgba(7, 8, 9, 0));
}
.hero__in {
  position: relative; z-index: 2; width: 100%; max-width: 1400px; margin: 0 auto;
  padding: calc(var(--head-h) + 40px) var(--gutter) clamp(36px, 6vh, 72px);
}
.hero__eyebrow { font-family: var(--mono); font-size: 13px; letter-spacing: .14em; color: var(--on-ink-2); margin-bottom: 26px; }
h1 { font-family: var(--serif); font-weight: 400; font-size: clamp(36px, 6.1vw, 92px); line-height: 1.2; letter-spacing: .005em; }
h1 span { display: block; }
.nb { display: inline-block; font-style: normal; }
.hero__foot { margin-top: clamp(26px, 4vh, 44px); padding-top: 22px; border-top: 1px solid var(--line-ink); display: flex; flex-wrap: wrap; align-items: center; justify-content: space-between; gap: 20px 40px; }
.hero__lead { font-size: clamp(17px, 1.5vw, 21px); color: var(--on-ink); }
.hero__actions { display: flex; gap: 12px; flex-wrap: wrap; }
.hero__note { position: absolute; z-index: 2; right: var(--gutter); top: calc(var(--head-h) + 18px); font-size: 12px; color: var(--on-ink-2); }

.btn {
  display: inline-flex; align-items: center; padding: 11px 26px; font-size: 16px; text-decoration: none;
  border: 1px solid rgba(237, 233, 225, .36); transition: background .2s, color .2s, border-color .2s;
}
.btn:hover { border-color: var(--on-ink); }
.btn--solid { background: var(--accent); border-color: var(--accent); color: #140a05; font-weight: 600; }
.btn--solid:hover { background: #f27c41; border-color: #f27c41; }

/* 章节通用 */
.sec { padding: var(--sec) 0; }
.sec--tight { padding-top: 0; }
.sec--paper { background: var(--paper); color: var(--on-paper); }
.sec--ink { background: var(--ink); }
.sec--deep { background: var(--deep); }

.grid { display: grid; grid-template-columns: minmax(180px, 3fr) 9fr; gap: 24px clamp(24px, 4vw, 64px); }
.label { font-size: 14px; color: var(--on-ink-2); padding-top: 14px; }
.label span { font-family: var(--mono); color: var(--accent); margin-right: 12px; }
.sec--paper .label { color: var(--on-paper-2); }
.sec--paper .label span { color: var(--accent-text); }
.eyebrow { font-size: 14px; color: var(--on-ink-2); }
.sec--paper .eyebrow { color: var(--on-paper-2); }

h2 { font-family: var(--serif); font-weight: 400; font-size: clamp(32px, 4.5vw, 66px); line-height: 1.26; letter-spacing: .005em; }
h3 { font-weight: 600; font-size: 19px; line-height: 1.45; }
.lede { margin-top: 30px; max-width: 46em; font-size: clamp(17px, 1.45vw, 20px); color: var(--on-ink-2); }
.sec--paper .lede { color: var(--on-paper-2); }

/* 01 判断 */
.cols { margin-top: 44px; display: grid; grid-template-columns: 1fr 1fr; gap: 30px clamp(28px, 4vw, 60px); color: var(--on-paper-2); }
.compare { width: 100%; margin-top: 60px; border-collapse: collapse; font-size: 16px; }
.compare th, .compare td { padding: 15px 16px 15px 0; text-align: left; vertical-align: top; border-top: 1px solid var(--line-paper); font-weight: 400; }
.compare thead th { border-top: 0; font-size: 14px; color: var(--on-paper-2); }
.compare tbody th { color: var(--on-paper-2); width: 22%; }
.compare td:last-child { color: var(--accent-text); }
.claim { margin-top: 56px; font-family: var(--serif); font-size: clamp(22px, 2.3vw, 32px); line-height: 1.55; }

/* 02 Harness */
.loop4 { margin-top: clamp(64px, 8vw, 110px); display: grid; grid-template-columns: repeat(4, 1fr); border-top: 1px solid var(--line-ink); }
.loop4 li { padding: 30px clamp(20px, 2.4vw, 34px) 34px 0; }
.loop4 li + li { border-left: 1px solid var(--line-ink); padding-left: clamp(20px, 2.4vw, 34px); }
.loop4 b { display: block; font-family: var(--serif); font-weight: 400; font-size: clamp(64px, 8vw, 118px); line-height: 1.1; }
.loop4 li:nth-child(3) b { color: var(--accent); }
.loop4 h3 { margin-top: 20px; }
.loop4 p { margin-top: 10px; font-size: 16px; color: var(--on-ink-2); }

.label--sub { padding-top: 6px; }
#harness .grid:last-child { margin-top: clamp(64px, 8vw, 110px); }
.deliver { display: grid; grid-template-columns: 1.1fr 1fr; gap: 28px clamp(28px, 5vw, 80px); }
.deliver > div > p { margin-top: 10px; color: var(--on-ink-2); font-size: 16px; }
.deliver dl > div { padding: 14px 0; border-top: 1px solid var(--line-ink); }
.deliver dl > div:first-child { border-top: 0; padding-top: 0; }
.deliver dt { font-weight: 600; }
.deliver dd { color: var(--on-ink-2); font-size: 16px; }

/* 03 世界模型 */
.stairs { margin-top: clamp(56px, 7vw, 96px); display: flex; flex-direction: column; gap: 6px; }
.stairs li {
  width: var(--w); min-width: min(100%, 620px); padding: 20px 24px;
  display: grid; grid-template-columns: 96px 170px 1fr; gap: 6px 20px; align-items: baseline;
  background: #17181a; color: var(--on-ink);
}
.stairs li:nth-child(1) { background: linear-gradient(90deg, #17181a 36%, #7a2d10); }
.stairs li:nth-child(2) { background: linear-gradient(90deg, #17181a 40%, #4a2212); }
.stairs li:nth-child(3) { background: linear-gradient(90deg, #17181a 46%, #2c1c15); }
.stairs__t { font-size: 14px; color: #f2a57e; }
.stairs p { font-size: 15px; color: var(--on-ink-2); }
.pull { margin-top: clamp(56px, 7vw, 96px); font-family: var(--serif); font-size: clamp(26px, 3.5vw, 50px); line-height: 1.4; }
.trio { margin-top: 64px; display: grid; grid-template-columns: repeat(3, 1fr); gap: 28px clamp(28px, 4vw, 60px); }
.trio > div { padding-top: 18px; border-top: 1px solid var(--line-paper); }
.trio p { margin-top: 8px; font-size: 16px; color: var(--on-paper-2); }

/* 04 飞轮 */
.fly { margin-top: clamp(56px, 7vw, 96px); display: grid; grid-template-columns: minmax(280px, 5fr) 7fr; gap: 40px clamp(40px, 7vw, 110px); align-items: center; }
.fly__ring svg { width: 100%; max-width: 460px; display: block; margin: 0 auto; overflow: visible; }
.r0 { fill: none; stroke: var(--line-ink); stroke-width: 1.5; }
.r1 { fill: none; stroke: var(--accent); stroke-width: 2; stroke-dasharray: 16 84; transform-origin: 200px 200px; transform: rotate(-90deg); }
html.js .r1 { animation: spin 16s linear infinite; }
@keyframes spin { to { transform: rotate(270deg); } }
.nodes circle { fill: var(--ink); stroke: rgba(237, 233, 225, .5); }
.nodes text { fill: var(--on-ink); font: 15px var(--mono); text-anchor: middle; }
.c1 { fill: var(--on-ink); font: 44px var(--serif); text-anchor: middle; }
.c2 { fill: var(--on-ink-2); font: 15px var(--sans); text-anchor: middle; }
.steps { counter-reset: s; }
.steps li { counter-increment: s; display: flex; align-items: center; justify-content: space-between; gap: 18px; padding: 20px 0; border-top: 1px solid var(--line-ink); }
.steps li:last-child { border-bottom: 1px solid var(--line-ink); }
.steps li > div { display: flex; gap: 18px; align-items: baseline; }
.steps li > div::before { content: counter(s); font-family: var(--mono); font-size: 14px; color: var(--on-ink-2); }
.steps h3 { font-weight: 400; font-size: clamp(17px, 1.5vw, 20px); }
.tag { flex: none; font-size: 13px; line-height: 1.5; color: var(--on-ink-2); border: 1px solid var(--line-ink); padding: 2px 10px; }
.tag--done { color: #f2a57e; border-color: rgba(232, 105, 43, .55); }

/* 05 成果 */
.case { margin-top: clamp(72px, 9vw, 128px); display: grid; grid-template-columns: 7fr 5fr; gap: 36px clamp(36px, 6vw, 96px); align-items: center; }
.case--flip { grid-template-columns: 5fr 7fr; }
.case--flip .case__fig { order: 2; }
.case__fig img { width: 100%; }
.case__fig figcaption { margin-top: 12px; font-size: 14px; color: var(--on-ink-2); }
.case__fig--light img { background: #fff; padding: 14px; }
.duo { display: grid; grid-template-columns: 1fr 1fr; gap: 6px; }
.duo figcaption { grid-column: 1 / -1; margin-top: 6px; }
.case__no { font-family: var(--serif); font-size: 22px; color: var(--accent); margin-bottom: 12px; }
.case__text h3 { font-family: var(--serif); font-weight: 400; font-size: clamp(25px, 2.5vw, 36px); line-height: 1.35; }
.case__text p:not(.case__no):not(.quote) { margin-top: 18px; color: var(--on-ink-2); }
.facts { margin-top: 28px; display: grid; grid-template-columns: 1fr 1fr; gap: 20px; border-top: 1px solid var(--line-ink); padding-top: 20px; }
.facts b { display: block; font-family: var(--serif); font-weight: 400; font-size: clamp(30px, 3.2vw, 44px); line-height: 1.2; }
.facts span { display: block; margin-top: 6px; font-size: 14px; line-height: 1.6; color: var(--on-ink-2); }
.quote { margin-top: 26px; padding-left: 18px; border-left: 2px solid var(--accent); font-family: var(--serif); font-size: clamp(20px, 1.8vw, 25px); line-height: 1.55; }
.not-yet { margin-top: clamp(72px, 9vw, 128px); }
.not-yet::before { content: ""; grid-column: 1 / -1; height: 1px; background: var(--line-ink); }
.not-yet li { padding: 8px 0; color: var(--on-ink-2); }
.not-yet li::before { content: ""; display: inline-block; width: 14px; height: 2px; margin-right: 12px; vertical-align: .32em; background: var(--accent); }

/* 06 产业 */
.fields { margin-top: clamp(56px, 7vw, 96px); display: grid; grid-template-columns: repeat(5, 1fr); border-top: 1px solid var(--line-paper); border-bottom: 1px solid var(--line-paper); }
.fields li { padding: 22px 18px 24px 0; }
.fields li + li { padding-left: 18px; border-left: 1px solid var(--line-paper); }
.fields h3 { font-family: var(--serif); font-weight: 400; font-size: clamp(20px, 1.9vw, 26px); }
.fields p { margin-top: 6px; font-size: 15px; color: var(--on-paper-2); }

.study { margin-top: clamp(56px, 7vw, 96px); padding: clamp(28px, 4.4vw, 64px); background: var(--ink); color: var(--on-ink); display: grid; grid-template-columns: 5fr 7fr; gap: 28px clamp(32px, 5vw, 76px); }
.study .eyebrow { color: #f2a57e; }
.study h3 { margin-top: 14px; font-family: var(--serif); font-weight: 400; font-size: clamp(27px, 3vw, 42px); line-height: 1.32; }
.study__body > p { color: var(--on-ink-2); }
.goals { margin: 26px 0; display: grid; grid-template-columns: auto auto auto; justify-content: space-between; gap: 18px clamp(16px, 2vw, 30px); border-top: 1px solid var(--line-ink); padding-top: 20px; }
.goals b { display: block; white-space: nowrap; font-family: var(--serif); font-weight: 400; font-size: clamp(22px, 2.1vw, 30px); line-height: 1.3; }
.goals span { display: block; margin-top: 6px; font-size: 14px; line-height: 1.6; color: var(--on-ink-2); }
.study .small { font-size: 15px; }

.how { margin-top: clamp(64px, 8vw, 110px); }
.howto { counter-reset: h; }
.howto li { counter-increment: h; display: grid; grid-template-columns: 48px minmax(0, 15em) 1fr; gap: 4px 16px; align-items: baseline; padding: 16px 0; border-top: 1px solid var(--line-paper); }
.howto li::before { content: counter(h); font-family: var(--mono); font-size: 14px; color: var(--accent-text); }
.howto li:first-child { border-top: 0; padding-top: 6px; }
.howto p { font-size: 16px; color: var(--on-paper-2); }

/* 07 伙伴 */
.partners__head { padding-top: 26px; border-top: 1px solid var(--line-paper); }
.group { margin-top: 32px; font-size: 14px; color: var(--on-paper-2); }
.logos { margin-top: 12px; display: grid; grid-template-columns: repeat(6, 1fr); gap: 1px; background: var(--line-paper); border: 1px solid var(--line-paper); }
.logos--five { grid-template-columns: repeat(5, 1fr); }
.logos li { background: #fff; min-height: 168px; padding: 24px 14px 16px; display: flex; flex-direction: column; align-items: center; justify-content: flex-end; gap: 16px; text-align: center; }
.logos img { flex: 1 1 auto; min-height: 0; max-height: 72px; width: auto; max-width: 92%; object-fit: contain; margin: auto; filter: grayscale(1) contrast(1.05); opacity: .78; transition: filter .25s, opacity .25s; }
.logos li:hover img { filter: none; opacity: 1; }
.logos span { font-size: 13px; line-height: 1.5; color: var(--on-paper-2); }
.logos__text { justify-content: center !important; }
.logos__text span { font-family: var(--serif); font-size: 20px; line-height: 1.45; color: var(--on-paper); }

/* 08 积累 */
.stats { margin-top: clamp(56px, 7vw, 96px); display: grid; grid-template-columns: repeat(5, 1fr); border-top: 1px solid var(--line-ink); }
.stats li { padding: 26px 18px 30px 0; border-bottom: 1px solid var(--line-ink); }
.stats__wide { grid-column: 1 / -1; }
.stats b { display: block; font-family: var(--serif); font-weight: 400; font-size: clamp(42px, 5vw, 72px); line-height: 1.15; }
.stats__wide b { font-size: clamp(44px, 9.4vw, 148px); color: var(--on-ink); }
.stats i { font-style: normal; font-size: .3em; margin-left: .3em; color: var(--on-ink-2); }
.stats span { display: block; margin-top: 8px; font-size: 15px; color: var(--on-ink-2); }
.honors { margin-top: 44px; columns: 2; column-gap: clamp(32px, 6vw, 90px); }
.honors li { break-inside: avoid; padding: 11px 0; border-bottom: 1px solid var(--line-ink); font-size: 16px; }

/* 09 关于 */
.values { margin-top: clamp(40px, 5vw, 64px); display: flex; flex-wrap: wrap; gap: 6px clamp(26px, 4.4vw, 62px); font-family: var(--serif); font-size: clamp(26px, 3vw, 42px); }

/* 联系 */
.contact { padding: clamp(80px, 11vw, 150px) 0; background: var(--accent); color: #140a05; }
.contact .eyebrow { color: #3a1705; }
.contact h2 { margin-top: 18px; }
.contact__grid { margin-top: clamp(40px, 6vw, 72px); display: grid; grid-template-columns: 1fr 1fr; gap: 28px clamp(32px, 6vw, 90px); }
.contact__grid > div { border-top: 1px solid rgba(20, 10, 5, .4); padding-top: 14px; }
.k { font-size: 14px; color: #3a1705; }
.phone { display: inline-block; margin-top: 8px; font-family: var(--serif); font-size: clamp(30px, 3.8vw, 52px); line-height: 1.25; text-decoration: none; white-space: nowrap; }
.phone:hover { text-decoration: underline; text-underline-offset: .15em; text-decoration-thickness: 1px; }
.contact :focus-visible { outline-color: #140a05; }
.contact__addr { grid-column: 1 / -1; }
.contact address { margin-top: 12px; font-size: clamp(17px, 1.5vw, 21px); }

.foot { padding: 26px 0; background: var(--deep); font-size: 14px; color: var(--on-ink-2); }
.foot__in { display: flex; flex-wrap: wrap; justify-content: space-between; gap: 6px 28px; }

/* 进入动效：仅在 JS 可用时隐藏，保证无脚本也能读 */
html.js .reveal { opacity: 0; transform: translateY(22px); transition: opacity .8s cubic-bezier(.2, .7, .2, 1), transform .8s cubic-bezier(.2, .7, .2, 1); }
html.js .reveal.is-in { opacity: 1; transform: none; }

@media (max-width: 1080px) {
  .grid { grid-template-columns: 1fr; }
  .label { padding-top: 0; }
  .loop4 { grid-template-columns: repeat(2, 1fr); }
  .loop4 li:nth-child(3) { border-left: 0; padding-left: 0; }
  .loop4 li:nth-child(n+3) { border-top: 1px solid var(--line-ink); }
  .fields { grid-template-columns: repeat(3, 1fr); }
  .fields li:nth-child(4) { border-left: 0; padding-left: 0; }
  .fields li:nth-child(n+4) { border-top: 1px solid var(--line-paper); }
  .fields li:last-child { grid-column: span 2; }
  .logos { grid-template-columns: repeat(3, 1fr); }
  .logos--five { grid-template-columns: repeat(3, 1fr); }
  .logos__text { grid-column: span 2; }
  .case, .case--flip, .study, .fly { grid-template-columns: 1fr; }
  .case--flip .case__fig { order: 0; }
  .stats { grid-template-columns: repeat(3, 1fr); }
}

@media (max-width: 820px) {
  .menu-btn { display: block; }
  .nav {
    position: absolute; left: 0; right: 0; top: var(--head-h); padding: 10px var(--gutter) 22px;
    display: none; flex-direction: column; align-items: stretch; gap: 0;
    background: rgba(12, 13, 15, .97); border-bottom: 1px solid var(--line-ink); font-size: 17px;
  }
  .nav.is-open { display: flex; }
  .nav a { padding: 12px 0; border-top: 1px solid var(--line-ink); color: var(--on-ink); }
  .nav .nav__cta { border-width: 1px 0 0; padding: 12px 0; }
  .top.is-open { background: rgba(12, 13, 15, .97); }
  .cols, .trio, .deliver, .contact__grid { grid-template-columns: 1fr; }
  .stairs li { width: 100%; min-width: 0; grid-template-columns: 1fr; padding: 16px 18px; }
  .goals { grid-template-columns: 1fr; justify-content: stretch; }
  .howto li { grid-template-columns: 32px 1fr; }
  .howto p { grid-column: 2; }
  .honors { columns: 1; }
  .hero__note { top: auto; bottom: 6px; right: var(--gutter); }
}

@media (max-width: 560px) {
  body { font-size: 16px; }
  .fields { grid-template-columns: repeat(2, 1fr); }
  .fields li:nth-child(n) { border-left: 0; padding-left: 0; border-top: 1px solid var(--line-paper); }
  .fields li:nth-child(even) { padding-left: 16px; border-left: 1px solid var(--line-paper); }
  .fields li:nth-child(-n+2) { border-top: 0; }
  .logos, .logos--five { grid-template-columns: repeat(2, 1fr); }
  .logos li { min-height: 140px; }
  .compare { font-size: 15px; }
  .compare th, .compare td { padding-right: 10px; }
  .btn { padding: 10px 20px; }
  .values { column-gap: 16px; }
  .hero__eyebrow { font-size: 11px; letter-spacing: .1em; margin-bottom: 18px; }
  .stats { grid-template-columns: repeat(2, 1fr); }
  .stats li:last-child { grid-column: 1 / -1; }
  .facts { gap: 14px; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  html.js .reveal { opacity: 1; transform: none; transition: none; }
  html.js .r1 { animation: none; }
}