@import url('https://fonts.googleapis.com/css2?family=Chakra+Petch:wght@300;400;500;600;700&family=Russo+One&display=swap');

:root {
  --ink: #1f1f1f;
  --paper: #ffffff;
  --mist: #f5f5f5;
  --line: #dfdfdf;
  --line-soft: #e9e9e9;
  --dim: #5c5c5c;
  --rail: 252px;
  --top: 40px;
  --r: 10px;
  --e1: 3px 3px 0 rgba(31, 31, 31, .92);
  --e2: 6px 6px 0 rgba(31, 31, 31, .9);
  --e3: 10px 10px 0 rgba(31, 31, 31, .14), 0 16px 34px -22px rgba(0, 0, 0, .5);
  --e4: 0 24px 48px -26px rgba(0, 0, 0, .55);
  --font-body: 'Chakra Petch', system-ui, -apple-system, 'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei', sans-serif;
  --font-head: 'Russo One', 'Chakra Petch', system-ui, 'PingFang SC', 'Microsoft YaHei', sans-serif;
}

* { box-sizing: border-box; }

html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  margin: 0;
  padding-left: var(--rail);
  background: var(--paper);
  color: var(--ink);
  font-family: var(--font-body);
  font-size: 17px;
  line-height: 1.75;
  -webkit-font-smoothing: antialiased;
}

img { max-width: 100%; height: auto; display: block; }

a { color: inherit; }

:focus-visible {
  outline: 3px solid var(--ink);
  outline-offset: 2px;
}

main { padding-top: var(--top); }

/* ---------- 左侧竖排栏 ---------- */
.rail {
  position: fixed;
  top: 0;
  bottom: 0;
  left: 0;
  width: var(--rail);
  z-index: 40;
  display: flex;
  flex-direction: column;
  gap: 10px;
  padding: 20px 16px 24px;
  background: var(--ink);
  color: #fff;
  border-right: 3px solid var(--ink);
  box-shadow: 10px 0 34px -22px rgba(0, 0, 0, .8);
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 6px 6px 16px;
  text-decoration: none;
  color: #fff;
  border-bottom: 1px solid #3b3b3b;
}

.brand-logo {
  width: 34px;
  height: 34px;
  flex: 0 0 auto;
  object-fit: contain;
  background: #fff;
  border-radius: 8px;
  padding: 2px;
}

.brand-dot {
  width: 15px;
  height: 15px;
  flex: 0 0 auto;
  background: #fff;
  border-radius: 3px;
  transform: rotate(45deg);
}

.brand-name {
  font-family: var(--font-head);
  font-size: 15px;
  letter-spacing: .04em;
  line-height: 1.3;
}

.railnav {
  display: flex;
  flex-direction: column;
  gap: 4px;
  overflow-y: auto;
  padding: 2px;
  flex: 1 1 auto;
}

.navlink {
  display: flex;
  align-items: center;
  gap: 10px;
  min-height: 44px;
  padding: 10px 12px;
  color: #e4e4e4;
  text-decoration: none;
  font-size: 16px;
  line-height: 1.3;
  border-radius: var(--r);
  border: 1px solid transparent;
  transition: background .18s ease, color .18s ease, transform .18s ease, box-shadow .18s ease;
}

.ico {
  width: 9px;
  height: 9px;
  flex: 0 0 auto;
  background: currentColor;
  transform: rotate(45deg);
  border-radius: 1px;
}

.navlink:nth-child(2n) .ico { border-radius: 50%; transform: none; }
.navlink:nth-child(3n) .ico { transform: rotate(0deg); width: 10px; height: 10px; border-radius: 2px; }

.navlink:hover {
  background: #fff;
  color: var(--ink);
  border-color: #fff;
  transform: translate3d(2px, -1px, 0);
  box-shadow: 4px 4px 0 rgba(255, 255, 255, .35);
}

.navlink[aria-current] {
  background: #fff;
  color: var(--ink);
  border-color: #fff;
  box-shadow: 4px 4px 0 rgba(255, 255, 255, .3);
}

/* ---------- 顶部细条 ---------- */
.topbar {
  position: fixed;
  top: 0;
  left: var(--rail);
  right: 0;
  height: var(--top);
  z-index: 35;
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 0 clamp(16px, 4vw, 42px);
  background: rgba(255, 255, 255, .76);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--line);
  font-size: 15px;
  letter-spacing: .08em;
  color: #3a3a3a;
  overflow: hidden;
  white-space: nowrap;
}

.pulse {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--ink);
  flex: 0 0 auto;
  animation: pulse 2.4s ease-in-out infinite;
}

@keyframes pulse {
  0%, 100% { transform: scale(1); opacity: 1; }
  50% { transform: scale(1.9); opacity: .45; }
}

/* ---------- 首屏 ---------- */
.hero {
  position: relative;
  min-height: calc(100vh - var(--top));
  display: flex;
  align-items: flex-start;
  overflow: hidden;
  background:
    radial-gradient(120% 90% at 88% 8%, #4a4a4a 0%, #2a2a2a 42%, #141414 100%);
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 76px), 0 100%);
  isolation: isolate;
}

.hero-media {
  position: absolute;
  inset: 0;
  overflow: hidden;
  z-index: 0;
}

.hero-media img,
.hero-img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  filter: grayscale(1) contrast(1.1) brightness(.62);
  transform: scale(1.02);
}

.hero-media::after {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(100deg, rgba(15, 15, 15, .92) 0%, rgba(15, 15, 15, .68) 52%, rgba(15, 15, 15, .3) 100%);
}

.hero::after {
  content: '';
  position: absolute;
  left: -6%;
  right: -6%;
  bottom: -26px;
  height: 58px;
  background: var(--mist);
  transform: rotate(-3deg);
  border-top: 3px solid var(--ink);
  z-index: 1;
}

.layers {
  position: absolute;
  inset: 0;
  z-index: 2;
  pointer-events: none;
}

.layer {
  position: absolute;
  border: 2px solid rgba(255, 255, 255, .5);
  border-radius: var(--r);
  background: rgba(255, 255, 255, .07);
  backdrop-filter: blur(2px);
  will-change: transform;
}

.l1 {
  width: 190px;
  height: 124px;
  right: 7%;
  top: 20%;
  transform: rotate(-7deg);
  box-shadow: 14px 14px 0 rgba(255, 255, 255, .14);
}

.l2 {
  width: 118px;
  height: 158px;
  right: 21%;
  top: 43%;
  transform: rotate(6deg);
  box-shadow: 9px 9px 0 rgba(255, 255, 255, .1);
}

.l3 {
  width: 84px;
  height: 84px;
  right: 6%;
  top: 64%;
  transform: rotate(13deg);
  box-shadow: 7px 7px 0 rgba(255, 255, 255, .16);
}

.hero-in {
  position: relative;
  z-index: 3;
  width: 100%;
  max-width: 1080px;
  padding: clamp(46px, 9vh, 104px) clamp(20px, 5vw, 66px) clamp(96px, 15vh, 168px);
  color: #fff;
  text-align: left;
}

.hero-kicker {
  margin: 0 0 14px;
  font-family: var(--font-head);
  font-size: 14px;
  letter-spacing: .22em;
  text-transform: uppercase;
  color: #d8d8d8;
  border-left: 5px solid #fff;
  padding-left: 10px;
}

.hero h1 {
  margin: 0 0 20px;
  max-width: 22ch;
  font-family: var(--font-head);
  font-weight: 400;
  font-size: clamp(34px, 5.6vw, 70px);
  line-height: 1.08;
  letter-spacing: .01em;
  text-shadow: 6px 6px 0 rgba(0, 0, 0, .55);
}

.hero-lede {
  margin: 0;
  max-width: 60ch;
  font-size: clamp(16px, 1.45vw, 19px);
  line-height: 1.8;
  color: #e7e7e7;
}

/* ---------- 主体 ---------- */
.wrap {
  max-width: 1200px;
  margin: 0 auto;
  padding: clamp(40px, 6vw, 76px) clamp(16px, 4vw, 40px) 0;
  display: grid;
  grid-template-columns: 264px minmax(0, 1fr);
  gap: clamp(20px, 2.6vw, 36px);
  align-items: start;
}

.side {
  position: sticky;
  top: calc(var(--top) + 20px);
  z-index: 2;
  background: var(--mist);
  border: 1px solid var(--line);
  border-radius: var(--r);
  padding: 20px 16px 14px;
  box-shadow: var(--e2);
}

.side h2 {
  margin: 0 0 6px;
  font-family: var(--font-head);
  font-size: 17px;
  line-height: 1.4;
  letter-spacing: .01em;
}

.subtitle {
  margin: 0 0 14px;
  font-size: 14px;
  letter-spacing: .1em;
  color: var(--dim);
}

.side-links {
  display: flex;
  flex-direction: column;
}

.side-links a {
  display: block;
  min-height: 42px;
  padding: 10px 6px;
  font-size: 15px;
  line-height: 1.4;
  text-decoration: none;
  color: var(--ink);
  border-bottom: 1px dashed #c9c9c9;
  transition: padding-left .16s ease, background .16s ease;
}

.side-links a:last-child { border-bottom: 0; }

.side-links a:hover {
  padding-left: 12px;
  background: #fff;
}

.body { min-width: 0; }

.doc {
  position: relative;
  background: var(--paper);
  border: 1px solid var(--line);
  border-radius: var(--r);
  padding: clamp(22px, 3.4vw, 46px) clamp(20px, 3.4vw, 46px) clamp(30px, 4vw, 54px);
  box-shadow: var(--e3), var(--e4);
  overflow: hidden;
}

.doc::after {
  content: '';
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  height: 6px;
  background: linear-gradient(90deg, var(--ink) 0 28%, #9a9a9a 28% 58%, #e2e2e2 58% 100%);
}

.doc > div {
  scroll-margin-top: calc(var(--top) + 26px);
  padding-bottom: 4px;
}

.doc > div + div {
  margin-top: 34px;
  padding-top: 32px;
  border-top: 1px solid var(--line-soft);
}

.doc h2 {
  margin: 0 0 14px;
  padding-left: 14px;
  border-left: 6px solid var(--ink);
  font-family: var(--font-head);
  font-weight: 400;
  font-size: clamp(22px, 2.5vw, 31px);
  line-height: 1.3;
  letter-spacing: .01em;
}

.doc h3 {
  margin: 26px 0 10px;
  font-size: clamp(18px, 1.9vw, 21px);
  line-height: 1.4;
  letter-spacing: .01em;
}

.doc h4 {
  margin: 20px 0 8px;
  font-size: 17px;
}

.doc p { margin: 0 0 1.05em; }

.doc h2 + p.subtitle,
.doc h2 + .subtitle { margin-top: -6px; }

.doc a {
  color: var(--ink);
  text-decoration: underline;
  text-decoration-thickness: 2px;
  text-underline-offset: 3px;
}

.doc a:hover { background: var(--mist); }

.doc ul,
.doc ol { margin: 0 0 1.1em; padding-left: 1.35em; }

.doc li { margin: .38em 0; }

.doc img {
  border-radius: var(--r);
  border: 1px solid var(--line);
  margin: .6em 0 1.2em;
}

.doc blockquote {
  margin: 0 0 1.2em;
  padding: 14px 18px;
  background: var(--mist);
  border-left: 6px solid var(--ink);
  border-radius: 0 var(--r) var(--r) 0;
}

.doc blockquote p:last-child { margin-bottom: 0; }

.doc table {
  width: 100%;
  border-collapse: collapse;
  display: block;
  overflow-x: auto;
  margin: 0 0 1.2em;
  font-size: 16px;
}

.doc th,
.doc td {
  border: 1px solid var(--line);
  padding: 9px 11px;
  text-align: left;
}

.doc th { background: var(--mist); }

.doc time { font-size: 14px; color: var(--dim); letter-spacing: .04em; }

.doc code {
  background: var(--mist);
  padding: .12em .38em;
  border-radius: 4px;
  font-size: .95em;
}

.doc hr {
  border: 0;
  border-top: 1px solid var(--line-soft);
  margin: 28px 0;
}

/* ---------- 页脚 ---------- */
.foot {
  margin-top: clamp(56px, 8vw, 96px);
  padding: clamp(34px, 5vw, 62px) clamp(18px, 4vw, 54px) 22px;
  background: var(--ink);
  color: #ededed;
  border-top: 8px solid var(--mist);
  display: grid;
  grid-template-columns: 1.6fr .85fr .8fr .8fr;
  gap: 26px;
  align-items: start;
}

.foot div { min-width: 0; }

.f-cta h2 {
  margin: 0 0 10px;
  font-family: var(--font-head);
  font-weight: 400;
  font-size: clamp(24px, 3.4vw, 40px);
  line-height: 1.12;
  color: #fff;
}

.f-cta .subtitle { margin: 0; }

.f-cta .subtitle a {
  display: inline-block;
  min-height: 40px;
  padding: 6px 0;
  font-size: 16px;
  color: #fff;
  text-decoration: none;
  border-bottom: 2px solid #fff;
}

.f-nav dl { margin: 0; }

.f-nav dd { margin: 0; }

.f-nav a {
  display: block;
  min-height: 40px;
  padding: 9px 0;
  font-size: 15px;
  color: #d6d6d6;
  text-decoration: none;
  border-bottom: 1px solid #373737;
  transition: color .16s ease, padding-left .16s ease;
}

.f-nav a:hover {
  color: #fff;
  padding-left: 8px;
}

.f-brand .brand-logo {
  width: 46px;
  height: 46px;
  border-radius: 8px;
  background: #fff;
  padding: 3px;
}

.f-brand .brand-dot {
  width: 20px;
  height: 20px;
  background: #fff;
  border-radius: 4px;
  transform: rotate(45deg);
}

.f-name {
  margin: 12px 0 0;
  font-size: 15px;
  color: #cfcfcf;
  line-height: 1.5;
}

.f-go { display: flex; justify-content: flex-end; }

.go-top {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 46px;
  padding: 12px 18px;
  background: #fff;
  color: var(--ink);
  font-size: 15px;
  font-weight: 600;
  text-decoration: none;
  border-radius: var(--r);
  box-shadow: 5px 5px 0 #6f6f6f;
  transition: transform .16s ease, box-shadow .16s ease;
}

.go-top:hover {
  transform: translate3d(-1px, -1px, 0);
  box-shadow: 7px 7px 0 #8b8b8b;
}

.f-bar {
  grid-column: 1 / -1;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  flex-wrap: wrap;
  margin-top: 8px;
  padding-top: 16px;
  border-top: 1px solid #3b3b3b;
  font-size: 14px;
  color: #b5b5b5;
}

.f-bar p { margin: 0; }

.f-bar-links { display: flex; gap: 6px; flex-wrap: wrap; }

.f-bar-links a {
  display: inline-block;
  min-height: 40px;
  padding: 9px 6px;
  color: #e4e4e4;
  text-decoration: none;
}

.f-bar-links a:hover { color: #fff; }

/* ---------- 动效 ---------- */
body.js-anim .rv,
body.js-anim .doc > div {
  opacity: 0;
  transform: translate3d(0, 18px, 0);
  transition: opacity .55s ease, transform .55s cubic-bezier(.22, .8, .3, 1);
}

body.js-anim .in {
  opacity: 1;
  transform: none;
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .pulse { animation: none; }
  body.js-anim .rv,
  body.js-anim .doc > div { opacity: 1; transform: none; transition: none; }
}

/* ---------- 断点 ---------- */
@media (max-width: 1100px) {
  :root { --rail: 226px; }
  .wrap { grid-template-columns: 220px minmax(0, 1fr); }
}

@media (max-width: 900px) {
  body { padding-left: 0; }

  .rail {
    position: static;
    width: auto;
    height: auto;
    flex-direction: row;
    align-items: center;
    gap: 8px;
    padding: 10px 12px;
    border-right: 0;
    border-bottom: 3px solid var(--ink);
    box-shadow: none;
  }

  .brand {
    padding: 6px;
    border-bottom: 0;
    flex: 0 0 auto;
  }

  .brand-name { display: none; }

  .railnav {
    flex-direction: row;
    overflow-x: auto;
    overflow-y: hidden;
    gap: 6px;
    padding: 2px 2px 4px;
    -webkit-overflow-scrolling: touch;
  }

  .navlink {
    white-space: nowrap;
    min-height: 44px;
    padding: 10px 12px;
    font-size: 15px;
  }

  .navlink:hover { transform: none; }

  .topbar {
    position: static;
    left: auto;
    height: auto;
    padding: 8px 14px;
    font-size: 14px;
  }

  main { padding-top: 0; }

  .hero {
    min-height: 82vh;
    clip-path: polygon(0 0, 100% 0, 100% calc(100% - 48px), 0 100%);
  }

  .hero-in { padding: 42px 20px 96px; }

  .layers { display: none; }

  .wrap {
    grid-template-columns: minmax(0, 1fr);
    padding-top: 30px;
    gap: 22px;
  }

  .side { position: static; }

  .doc { box-shadow: 6px 6px 0 #ececec; }

  .foot { grid-template-columns: 1fr 1fr; gap: 20px; }

  .f-cta { grid-column: 1 / -1; }

  .f-go { justify-content: flex-start; }

  .f-bar { flex-direction: column; align-items: flex-start; }
}

@media (max-width: 520px) {
  body { font-size: 16px; }

  .hero h1 { font-size: clamp(30px, 9vw, 40px); max-width: 18ch; }

  .foot { grid-template-columns: minmax(0, 1fr); }
}

button[aria-expanded]{min-width:44px;min-height:44px}