:root {
  --ink: #191918;
  --muted: #5d5b55;
  --paper: #f6f1e8;
  --paper-strong: #fffaf0;
  --line: rgba(25, 25, 24, 0.14);
  --river: #0f6670;
  --cyan: #2eb7bd;
  --gold: #c49a54;
  --coral: #bf594b;
  --night: #0d1d24;
  --white: #ffffff;
  --shadow: 0 20px 70px rgba(15, 29, 36, 0.18);
  color-scheme: light;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: "Geist", "Avenir Next", "PingFang SC", "Microsoft YaHei", Arial, sans-serif;
  letter-spacing: 0;
}

.friends-feature {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0;
  padding-top: 0;
  padding-bottom: 0;
  margin-bottom: 120px;
  color: var(--white);
  background: var(--night);
}

.friends-feature__visual {
  min-height: 620px;
  overflow: hidden;
}

.friends-feature__visual img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.friends-feature__copy {
  display: flex;
  flex-direction: column;
  justify-content: flex-end;
  padding: clamp(40px, 4.5vw, 68px);
}

.friends-feature__copy h2 {
  margin-bottom: 30px;
  font-size: clamp(3.2rem, 4.2vw, 4.9rem);
  line-height: 0.94;
}

.friends-feature__copy p {
  margin: 0 0 30px;
  color: rgba(255, 255, 255, 0.7);
  line-height: 1.85;
}

.friends-feature__copy .text-link { color: #73dce7; }

body.nav-open {
  overflow: hidden;
}

a {
  color: inherit;
  text-decoration: none;
}

img,
canvas {
  display: block;
}

.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 50;
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 76px;
  padding: 0 34px;
  color: var(--white);
  transition: background 180ms ease, color 180ms ease, border 180ms ease;
}

.site-header.is-scrolled,
.site-header.is-open {
  background: rgba(246, 241, 232, 0.94);
  color: var(--ink);
  border-bottom: 1px solid var(--line);
  backdrop-filter: blur(18px);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  min-width: 230px;
}

.brand-mark {
  display: grid;
  place-items: center;
  width: 44px;
  height: 44px;
  border: 1px solid currentColor;
  background: rgba(255, 255, 255, 0.12);
  font-size: 0.82rem;
  font-weight: 800;
}

.brand-text {
  display: grid;
  gap: 2px;
}

.brand-text strong {
  font-size: 1rem;
  font-weight: 760;
}

.brand-text small {
  color: currentColor;
  font-size: 0.72rem;
  opacity: 0.72;
  text-transform: uppercase;
}

.site-nav {
  display: flex;
  align-items: center;
  gap: 28px;
  font-size: 0.94rem;
}

.site-nav a {
  position: relative;
  opacity: 0.84;
  padding: 28px 0;
}

.site-nav a::after {
  position: absolute;
  left: 0;
  right: 0;
  bottom: 20px;
  height: 2px;
  background: currentColor;
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 180ms ease;
  content: "";
}

.site-nav a:hover,
.site-nav a.is-active {
  opacity: 1;
}

.site-nav a:hover::after,
.site-nav a.is-active::after {
  transform: scaleX(1);
}

.nav-toggle {
  display: none;
  width: 44px;
  height: 44px;
  padding: 0;
  border: 1px solid currentColor;
  background: transparent;
  color: inherit;
  cursor: pointer;
}

.nav-toggle span {
  display: block;
  width: 18px;
  height: 2px;
  margin: 4px auto;
  background: currentColor;
}

.hero {
  position: relative;
  min-height: 82svh;
  display: grid;
  align-items: end;
  overflow: hidden;
  background: var(--night);
  color: var(--white);
  padding: 112px 34px 30px;
}

.hero-image {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  filter: saturate(0.96) contrast(1.04);
}

.hero-shade {
  position: absolute;
  inset: 0;
  background:
    linear-gradient(90deg, rgba(8, 17, 22, 0.9) 0%, rgba(8, 17, 22, 0.68) 36%, rgba(8, 17, 22, 0.22) 74%, rgba(8, 17, 22, 0.5) 100%),
    linear-gradient(0deg, rgba(8, 17, 22, 0.84) 0%, rgba(8, 17, 22, 0) 45%);
}

.signal-canvas {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  opacity: 0.55;
  mix-blend-mode: screen;
  pointer-events: none;
}

.hero-content {
  position: relative;
  z-index: 2;
  max-width: 850px;
  padding-bottom: 88px;
}

.eyebrow,
.section-kicker {
  margin: 0 0 18px;
  color: var(--gold);
  font-size: 0.76rem;
  font-weight: 800;
  letter-spacing: 0;
  text-transform: uppercase;
}

.hero h1 {
  margin: 0;
  font-family: "Georgia", "Songti SC", "SimSun", serif;
  font-size: 5.7rem;
  line-height: 0.98;
  font-weight: 700;
  letter-spacing: 0;
}

.hero h1 span {
  color: #f4d9a3;
}

.hero-lede {
  max-width: 670px;
  margin: 24px 0 0;
  color: rgba(255, 255, 255, 0.86);
  font-size: 1.28rem;
  line-height: 1.78;
}

.hero-actions,
.join-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 28px;
}

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  min-height: 46px;
  padding: 0 18px;
  border: 1px solid currentColor;
  font-weight: 760;
  transition: transform 180ms ease, background 180ms ease, color 180ms ease, border 180ms ease;
}

.button:hover {
  transform: translateY(-2px);
}

.button.primary {
  border-color: #f0c572;
  background: #f0c572;
  color: #16120b;
}

.button.ghost {
  color: var(--white);
  background: rgba(255, 255, 255, 0.08);
  backdrop-filter: blur(12px);
}

.button.dark {
  background: var(--ink);
  color: var(--white);
  border-color: var(--ink);
}

.hero-panel {
  position: absolute;
  z-index: 3;
  right: 34px;
  bottom: 30px;
  display: grid;
  grid-template-columns: repeat(3, minmax(140px, 1fr));
  max-width: 680px;
  border: 1px solid rgba(255, 255, 255, 0.24);
  background: rgba(10, 20, 25, 0.42);
  backdrop-filter: blur(18px);
}

.hero-panel div {
  min-height: 108px;
  padding: 22px;
  border-right: 1px solid rgba(255, 255, 255, 0.2);
}

.hero-panel div:last-child {
  border-right: 0;
}

.hero-panel strong {
  display: block;
  color: #f6d28c;
  font-size: 1.42rem;
}

.hero-panel span {
  display: block;
  margin-top: 10px;
  color: rgba(255, 255, 255, 0.76);
  font-size: 0.88rem;
  line-height: 1.5;
}

.ticker {
  display: flex;
  gap: 1px;
  background: var(--ink);
  overflow-x: auto;
  scrollbar-width: none;
}

.ticker span {
  flex: 1 0 auto;
  min-width: 170px;
  padding: 18px 22px;
  border-right: 1px solid rgba(255, 255, 255, 0.12);
  color: #f4efe4;
  text-align: center;
  font-size: 0.78rem;
  font-weight: 800;
  text-transform: uppercase;
}

.section {
  max-width: 1220px;
  margin: 0 auto;
  padding: 96px 34px;
}

.intro-grid,
.dialogue,
.join-inner {
  display: grid;
  grid-template-columns: minmax(0, 0.95fr) minmax(0, 1.05fr);
  gap: 72px;
  align-items: start;
}

h2 {
  margin: 0;
  font-family: "Georgia", "Songti SC", "SimSun", serif;
  font-size: 3.25rem;
  line-height: 1.12;
  letter-spacing: 0;
}

h3 {
  margin: 0;
  font-size: 1.18rem;
  line-height: 1.42;
  letter-spacing: 0;
}

p {
  margin: 0;
}

.intro-copy {
  display: grid;
  gap: 18px;
  color: var(--muted);
  font-size: 1.04rem;
  line-height: 1.9;
}

.metrics {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 1px;
  margin-top: 64px;
  background: var(--line);
  border: 1px solid var(--line);
}

.metric {
  min-height: 160px;
  padding: 26px;
  background: var(--paper-strong);
}

.metric span {
  color: var(--river);
  font-size: 2.1rem;
  font-weight: 820;
}

.metric p {
  margin-top: 18px;
  color: var(--muted);
  line-height: 1.6;
}

.section-heading {
  display: grid;
  grid-template-columns: minmax(0, 1.15fr) minmax(260px, 0.85fr);
  gap: 64px;
  align-items: end;
  margin-bottom: 44px;
}

.section-heading p {
  color: var(--muted);
  font-size: 1rem;
  line-height: 1.8;
}

.programs {
  max-width: none;
  background: #ece4d6;
}

.programs > * {
  max-width: 1152px;
  margin-left: auto;
  margin-right: auto;
}

.program-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 14px;
}

.program-card {
  position: relative;
  min-height: 280px;
  padding: 28px;
  border: 1px solid rgba(25, 25, 24, 0.12);
  border-radius: 8px;
  background: #fffaf0;
  box-shadow: none;
  overflow: hidden;
}

.program-card::before {
  position: absolute;
  left: 0;
  top: 0;
  width: 5px;
  height: 100%;
  background: var(--accent);
  content: "";
}

.program-card h3 {
  margin-top: 44px;
}

.program-card p {
  margin-top: 18px;
  color: var(--muted);
  line-height: 1.75;
}

.card-number {
  position: absolute;
  top: 24px;
  left: 28px;
  color: var(--accent);
  font-weight: 900;
}

.accent-cyan {
  --accent: var(--river);
}

.accent-gold {
  --accent: var(--gold);
}

.accent-coral {
  --accent: var(--coral);
}

.accent-ink {
  --accent: var(--ink);
}

.wide-card {
  grid-column: span 3;
  min-height: 170px;
}

.wide-card h3 {
  margin-top: 34px;
}

.ai-calls {
  display: grid;
  grid-template-columns: minmax(0, 0.86fr) minmax(0, 1.14fr);
  gap: 72px;
  align-items: start;
}

.ai-calls > .section-kicker {
  grid-column: 1 / -1;
  margin-bottom: -44px;
}

.tab-shell {
  border: 1px solid var(--line);
  background: var(--paper-strong);
  box-shadow: var(--shadow);
}

.tab-list {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  border-bottom: 1px solid var(--line);
}

.tab-button {
  min-height: 58px;
  border: 0;
  border-right: 1px solid var(--line);
  background: transparent;
  color: var(--muted);
  font: inherit;
  font-weight: 780;
  cursor: pointer;
}

.tab-button:last-child {
  border-right: 0;
}

.tab-button.is-active {
  background: var(--ink);
  color: var(--white);
}

.tab-panel {
  display: none;
  min-height: 290px;
  padding: 32px;
}

.tab-panel.is-active {
  display: block;
}

.tab-panel p {
  color: var(--muted);
  font-size: 1.08rem;
  line-height: 1.9;
}

.tab-panel ul {
  display: grid;
  gap: 12px;
  margin: 28px 0 0;
  padding: 0;
  list-style: none;
}

.tab-panel li {
  padding: 14px 16px;
  border-left: 4px solid var(--gold);
  background: rgba(196, 154, 84, 0.12);
  font-weight: 760;
}

.dialogue {
  max-width: none;
  background: var(--night);
  color: var(--white);
}

.dialogue-panel,
.dialogue-list {
  max-width: 560px;
}

.dialogue-panel {
  justify-self: end;
}

.dialogue-panel p {
  margin-top: 24px;
  color: rgba(255, 255, 255, 0.74);
  line-height: 1.9;
}

.country-line {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 30px;
}

.country-line span {
  padding: 8px 10px;
  border: 1px solid rgba(255, 255, 255, 0.18);
  color: #f5d68d;
  font-size: 0.78rem;
  font-weight: 800;
}

.dialogue-list {
  display: grid;
  gap: 1px;
  background: rgba(255, 255, 255, 0.14);
}

.dialogue-list article {
  padding: 30px;
  background: rgba(255, 255, 255, 0.06);
}

.dialogue-list p {
  margin-top: 12px;
  color: rgba(255, 255, 255, 0.68);
  line-height: 1.75;
}

.experience {
  background:
    linear-gradient(90deg, rgba(15, 102, 112, 0.08), transparent 40%),
    var(--paper);
}

.route-board {
  display: grid;
  grid-template-columns: minmax(0, 1.2fr) minmax(280px, 0.8fr);
  gap: 1px;
  border: 1px solid var(--line);
  background: var(--line);
}

.route-map {
  position: relative;
  min-height: 360px;
  background:
    linear-gradient(135deg, rgba(15, 102, 112, 0.12), rgba(196, 154, 84, 0.12)),
    #fffaf0;
  overflow: hidden;
}

.river-line {
  position: absolute;
  left: 6%;
  right: 6%;
  top: 53%;
  height: 3px;
  background: var(--river);
  transform: rotate(-8deg);
}

.river-line::before,
.river-line::after {
  position: absolute;
  left: 0;
  right: 0;
  height: 1px;
  background: rgba(15, 102, 112, 0.28);
  content: "";
}

.river-line::before {
  top: -26px;
}

.river-line::after {
  top: 26px;
}

.route-map i {
  position: absolute;
  width: 18px;
  height: 18px;
  border: 3px solid var(--paper-strong);
  background: var(--coral);
  box-shadow: 0 0 0 8px rgba(191, 89, 75, 0.14);
  transform: translate(-50%, -50%);
}

.route-copy {
  display: grid;
  align-content: center;
  padding: 38px;
  background: var(--paper-strong);
}

.route-copy p {
  margin-top: 18px;
  color: var(--muted);
  line-height: 1.8;
}

.text-link {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  margin-top: 28px;
  color: var(--river);
  font-weight: 850;
}

.timeline {
  max-width: none;
  background: #fffaf0;
}

.timeline > .section-kicker,
.timeline > h2,
.timeline-track {
  max-width: 1152px;
  margin-left: auto;
  margin-right: auto;
}

.timeline-track {
  position: relative;
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 18px;
  margin-top: 48px;
}

.timeline-track article {
  min-height: 230px;
  padding: 28px;
  border-top: 4px solid var(--river);
  background: var(--paper);
}

.timeline-track span {
  color: var(--coral);
  font-size: 0.84rem;
  font-weight: 850;
}

.timeline-track h3 {
  margin-top: 24px;
}

.timeline-track p {
  margin-top: 14px;
  color: var(--muted);
  line-height: 1.72;
}

.partner-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 1px;
  border: 1px solid var(--line);
  background: var(--line);
}

.partner-grid span {
  display: grid;
  min-height: 92px;
  place-items: center;
  padding: 18px;
  background: var(--paper-strong);
  text-align: center;
  line-height: 1.5;
  font-weight: 760;
}

.join {
  max-width: none;
  background:
    linear-gradient(90deg, rgba(25, 25, 24, 0.88), rgba(25, 25, 24, 0.66)),
    url("assets/haihe-hero.png") center / cover;
  color: var(--white);
}

.join-inner {
  max-width: 1152px;
  margin: 0 auto;
  align-items: center;
}

.join p {
  margin-top: 22px;
  color: rgba(255, 255, 255, 0.74);
  line-height: 1.9;
}

.join-actions {
  justify-content: flex-end;
  margin-top: 0;
}

.site-footer {
  display: flex;
  flex-wrap: wrap;
  gap: 12px 28px;
  justify-content: space-between;
  padding: 30px 34px;
  background: var(--ink);
  color: rgba(255, 255, 255, 0.74);
  font-size: 0.88rem;
}

@media (max-width: 1060px) {
  .hero h1 {
    font-size: 4.35rem;
  }

  .hero-content {
    padding-bottom: 170px;
  }

  .hero-panel {
    left: 34px;
    right: 34px;
    max-width: none;
  }

  .intro-grid,
  .dialogue,
  .join-inner,
  .ai-calls {
    grid-template-columns: 1fr;
    gap: 38px;
  }

  .ai-calls > .section-kicker {
    margin-bottom: -16px;
  }

  .program-grid,
  .timeline-track {
    grid-template-columns: repeat(2, 1fr);
  }

  .wide-card {
    grid-column: span 2;
  }

  .metrics,
  .partner-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .dialogue-panel,
  .dialogue-list {
    justify-self: auto;
    max-width: none;
  }
}

@media (max-width: 820px) {
  .site-header {
    height: 66px;
    padding: 0 18px;
  }

  .brand {
    min-width: 0;
  }

  .brand-mark {
    width: 40px;
    height: 40px;
  }

  .brand-text strong {
    font-size: 0.95rem;
  }

  .nav-toggle {
    display: block;
  }

  .site-nav {
    position: fixed;
    left: 16px;
    right: 16px;
    top: 76px;
    display: none;
    padding: 16px;
    border: 1px solid var(--line);
    background: var(--paper-strong);
    color: var(--ink);
    box-shadow: var(--shadow);
  }

  .site-header.is-open .site-nav {
    display: grid;
    gap: 0;
  }

  .site-nav a {
    padding: 16px 6px;
    border-bottom: 1px solid var(--line);
  }

  .site-nav a:last-child {
    border-bottom: 0;
  }

  .site-nav a::after {
    display: none;
  }

  .hero {
    display: block;
    min-height: auto;
    padding: 100px 20px 20px;
  }

  .hero-shade {
    background:
      linear-gradient(90deg, rgba(8, 17, 22, 0.92), rgba(8, 17, 22, 0.48)),
      linear-gradient(0deg, rgba(8, 17, 22, 0.9) 0%, rgba(8, 17, 22, 0) 44%);
  }

  .hero-content {
    padding-bottom: 0;
  }

  .hero h1 {
    font-size: 3.28rem;
  }

  .hero-lede {
    font-size: 1.03rem;
    line-height: 1.75;
  }

  .hero-panel {
    position: relative;
    left: auto;
    right: auto;
    bottom: auto;
    grid-template-columns: 1fr;
    margin-top: 26px;
  }

  .hero-panel div {
    min-height: 74px;
    padding: 16px;
    border-right: 0;
    border-bottom: 1px solid rgba(255, 255, 255, 0.2);
  }

  .hero-panel div:last-child {
    border-bottom: 0;
  }

  .section {
    padding: 72px 20px;
  }

  h2 {
    font-size: 2.18rem;
  }

  .section-heading {
    grid-template-columns: 1fr;
    gap: 22px;
  }

  .program-grid,
  .timeline-track,
  .metrics,
  .partner-grid,
  .route-board {
    grid-template-columns: 1fr;
  }

  .friends-feature {
    grid-template-columns: 1fr;
    margin-bottom: 72px;
  }

  .friends-feature__visual { min-height: 340px; }

  .friends-feature__copy { min-height: 460px; padding: 42px 26px; }

  .wide-card {
    grid-column: span 1;
  }

  .program-card {
    min-height: 230px;
  }

  .tab-list {
    grid-template-columns: 1fr;
  }

  .tab-button {
    border-right: 0;
    border-bottom: 1px solid var(--line);
  }

  .route-map {
    min-height: 280px;
  }

  .join-actions {
    justify-content: flex-start;
  }

  .site-footer {
    padding: 24px 20px;
  }
}

@media (max-width: 440px) {
  .hero h1 {
    font-size: 2.72rem;
  }

  .hero-actions,
  .join-actions {
    display: grid;
  }

  .button {
    width: 100%;
  }

  .brand-text small {
    display: none;
  }
}