:root {
  color-scheme: light;
  --ink: #0d1829;
  --muted: #4e6076;
  --line: #dce8f1;
  --blue: #236ff2;
  --navy: #173357;
  --mint: #29d8b0;
  --page-width: 920px;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  color: var(--ink);
  background: #fff;
  font-family: Inter, ui-sans-serif, -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", Arial, sans-serif;
  -webkit-font-smoothing: antialiased;
}
a { color: inherit; text-decoration: none; }
button { font: inherit; }

.site-header {
  height: 69px;
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  align-items: center;
  gap: 30px;
  padding: 0 max(36px, calc((100vw - 1380px) / 2));
  border-bottom: 1px solid rgba(20, 64, 85, .13);
  background: rgba(255,255,255,.92);
  backdrop-filter: blur(18px);
  position: sticky;
  top: 0;
  z-index: 20;
}
.brand { display: flex; align-items: center; width: max-content; gap: 8px; font-weight: 800; }
.brand-mark { width: 37px; height: 37px; }
.brand-name { font-size: 27px; letter-spacing: -.8px; }
.brand-cn { font-size: 14px; margin-left: 1px; font-weight: 600; }
.desktop-nav { display: flex; align-items: stretch; height: 100%; gap: 38px; font-weight: 650; }
.desktop-nav a { display: flex; align-items: center; position: relative; }
.desktop-nav a::after { content: ""; position: absolute; height: 2px; left: 20%; right: 20%; bottom: 16px; background: var(--mint); transform: scaleX(0); transition: .2s; }
.desktop-nav a:hover::after, .desktop-nav a.active::after { transform: scaleX(1); }
.header-actions { justify-self: end; display: flex; gap: 14px; }
.button { display: inline-flex; align-items: center; justify-content: center; border-radius: 11px; font-weight: 700; transition: transform .2s, box-shadow .2s, border-color .2s; }
.button:hover, .mini-button:hover { transform: translateY(-2px); }
.button-login { height: 39px; min-width: 72px; border: 1px solid #d8e1ec; }
.button-register { height: 39px; min-width: 72px; color: #fff; background: #0c1523; box-shadow: 0 8px 18px rgba(15,25,40,.18); }
.menu-button, .mobile-nav { display: none; }

.hero-section {
  min-height: 915px;
  padding: 52px 24px 58px;
  overflow: hidden;
  background:
    radial-gradient(circle at 76% 17%, rgba(255,241,123,.37), transparent 19%),
    radial-gradient(circle at 81% 69%, rgba(75,239,196,.21), transparent 28%),
    linear-gradient(115deg, #f8fdff 0%, #e7f9ff 52%, #f4fffb 100%);
}
.hero-grid {
  width: min(var(--page-width), 100%);
  margin: 0 auto;
  display: grid;
  grid-template-columns: 1fr 300px;
  align-items: center;
  gap: 92px;
}
.hero-copy { padding-top: 6px; }
.hero-kicker { margin: 0 0 2px; font-size: 34px; line-height: 1.22; letter-spacing: -1.5px; }
.hero-copy h1 { margin: 0; font-size: 49px; line-height: 1.2; letter-spacing: -2.7px; }
.hero-subtitle { margin: 44px 0; font-size: 14px; }
.hero-subtitle strong { font-weight: 500; }
.hero-actions { display: flex; gap: 17px; }
.primary-button { min-width: 132px; height: 43px; padding: 0 25px; color: #fff; background: linear-gradient(120deg, #183553, #1266e8); box-shadow: 0 14px 28px rgba(25,91,177,.25); }
.secondary-button { min-width: 116px; height: 43px; padding: 0 18px; border: 1px solid #d2deeb; background: rgba(255,255,255,.84); }

.model-window {
  height: 330px;
  border-radius: 20px;
  padding-top: 39px;
  background: linear-gradient(135deg, rgba(222,251,255,.86), rgba(255,251,185,.64));
  border: 1px solid rgba(255,255,255,.9);
  box-shadow: 0 20px 48px rgba(46,117,139,.14), inset 0 0 0 1px rgba(255,255,255,.35);
  position: relative;
}
.window-bar { position: absolute; display: flex; gap: 8px; top: 19px; left: 25px; }
.window-bar i { width: 7px; height: 7px; border-radius: 50%; background: #ff7081; }
.window-bar i:nth-child(2) { background: #ffb629; }
.window-bar i:nth-child(3) { background: #34c997; }
.model-card {
  height: 290px;
  border-radius: 19px;
  padding: 3px 28px 12px;
  background: rgba(255,255,255,.91);
  box-shadow: 0 10px 0 rgba(255,255,255,.5);
}
.model-card h2 { margin: 0 0 32px; font-size: 22px; letter-spacing: -.7px; }
.model-card p { height: 43px; margin: 0 0 14px; font-size: 12px; line-height: 1.55; color: #56657a; }
.model-card ul { margin: 0; padding: 0; list-style: none; }
.model-card li { display: flex; justify-content: space-between; align-items: center; min-height: 35px; border-bottom: 1px solid #e7edf2; font-size: 12px; }
.model-card li:last-child { border-bottom: 0; }
.model-card li span { color: #53657b; }
.model-card li .blue { color: #156cff; }
.model-card li .green { color: #00a77d; }
.model-card li .orange { color: #ff8a00; }

.use-cases { width: min(var(--page-width), 100%); margin: 51px auto 0; text-align: center; }
.use-cases > h2 { margin: 0; font-size: 29px; letter-spacing: -.8px; }
.use-cases > p { margin: 6px 0 16px; font-size: 11px; }
.mini-button { display: inline-flex; align-items: center; justify-content: center; height: 35px; min-width: 96px; padding: 0 18px; border-radius: 999px; color: #fff; font-size: 12px; font-weight: 700; background: #2d76ee; box-shadow: 0 9px 18px rgba(38,105,224,.25); transition: transform .2s; }
.role-tabs { display: grid; grid-template-columns: repeat(8, 1fr); gap: 36px; margin-top: 44px; }
.role-tab {
  appearance: none;
  border: 0;
  padding: 0;
  height: 84px;
  border-radius: 15px;
  overflow: hidden;
  position: relative;
  background: #d7e9f7;
  cursor: pointer;
  box-shadow: inset 0 0 0 1px rgba(17,56,90,.06);
  transition: transform .2s, box-shadow .2s;
}
.role-tab:hover { transform: translateY(-3px); }
.role-tab.active { box-shadow: 0 0 0 2px #2675ff, 0 8px 18px rgba(35,102,208,.17); }
.role-tab img { width: 100%; height: 100%; object-fit: cover; display: block; }
.role-tab span { position: absolute; left: 0; right: 0; bottom: 0; padding: 6px 1px; color: #fff; background: rgba(7,22,43,.78); font-size: 11px; font-weight: 800; }
.estimate-card {
  min-height: 170px;
  margin-top: 20px;
  padding: 23px;
  border: 1px solid #9fcaff;
  border-radius: 13px;
  background: rgba(255,255,255,.75);
  text-align: left;
  position: relative;
}
.card-pointer { position: absolute; width: 18px; height: 18px; top: -10px; left: 41px; transform: rotate(45deg); background: #f7feff; border-left: 1px solid #9fcaff; border-top: 1px solid #9fcaff; transition: left .25s ease; }
.estimate-card h3 { margin: 0 0 15px; font-size: 15px; font-weight: 650; }
.estimate-card h3 strong { color: #1d63f0; }
.person-line { display: flex; align-items: center; gap: 11px; }
.person-line img { width: 29px; height: 29px; object-fit: cover; border-radius: 50%; }
.person-line p { margin: 0; font-size: 14px; line-height: 1.55; }
.person-line p strong { font-size: 12px; }
.estimate-card small { display: block; margin-top: 21px; font-size: 11px; color: #718097; }

.closing-section { text-align: center; padding: 76px 24px 84px; background: #fff; }
.closing-section p { margin: 0 0 10px; color: #2471eb; font-weight: 700; }
.closing-section h2 { margin: 0 auto 28px; max-width: 620px; font-size: 32px; }
footer { min-height: 74px; padding: 20px max(24px, calc((100vw - 920px)/2)); display: flex; justify-content: space-between; align-items: center; border-top: 1px solid #edf1f5; color: #748197; font-size: 13px; }
footer div { display: flex; gap: 24px; }

@media (max-width: 760px) {
  .site-header { height: 69px; grid-template-columns: 1fr auto; padding: 0 16px; }
  .brand { gap: 5px; }
  .brand-mark { width: 30px; height: 30px; }
  .brand-name { font-size: 19px; }
  .brand-cn { font-size: 12px; }
  .desktop-nav, .header-actions { display: none; }
  .menu-button { display: flex; flex-direction: column; justify-content: center; gap: 5px; width: 40px; height: 40px; border: 0; border-radius: 10px; background: transparent; }
  .menu-button span { width: 22px; height: 2px; margin: 0 auto; background: #172436; transition: .2s; }
  .menu-button[aria-expanded="true"] span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
  .menu-button[aria-expanded="true"] span:nth-child(2) { opacity: 0; }
  .menu-button[aria-expanded="true"] span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }
  .mobile-nav { position: fixed; z-index: 19; top: 69px; left: 0; right: 0; padding: 12px 16px 18px; display: grid; gap: 4px; background: rgba(255,255,255,.98); border-bottom: 1px solid #e2eaf1; box-shadow: 0 18px 32px rgba(30,60,82,.12); transform: translateY(-130%); transition: transform .25s ease; }
  .mobile-nav.open { transform: translateY(0); }
  .mobile-nav a { padding: 12px 14px; border-radius: 9px; font-weight: 650; }
  .mobile-nav a:hover { background: #f0f6ff; }
  .mobile-nav .mobile-register { color: #fff; background: #111b2a; text-align: center; }

  .hero-section { min-height: 0; padding: 38px 16px 44px; }
  .hero-grid { grid-template-columns: 1fr; gap: 22px; }
  .hero-copy { padding: 0; }
  .hero-kicker { font-size: 27px; letter-spacing: -1px; }
  .hero-copy h1 { font-size: clamp(34px, 10vw, 43px); letter-spacing: -2px; white-space: nowrap; }
  .hero-subtitle { margin: 36px 0 31px; font-size: 13px; }
  .hero-actions { gap: 10px; }
  .hero-actions .button { flex: 1; min-width: 0; padding: 0 12px; }
  .model-window { width: 100%; height: 227px; border-radius: 19px; padding-top: 39px; }
  .model-card { height: 198px; border-radius: 19px; padding: 1px 16px 7px; }
  .model-card h2 { margin-bottom: 8px; font-size: 23px; }
  .model-card p { height: auto; margin-bottom: 9px; font-size: 11px; }
  .model-card li { min-height: 27px; font-size: 11px; }
  .use-cases { margin-top: 47px; }
  .use-cases > h2 { font-size: 25px; white-space: nowrap; }
  .use-cases > p { margin-top: 8px; }
  .role-tabs { display: flex; gap: 5px; margin: 42px -1px 0; overflow-x: auto; scrollbar-width: none; }
  .role-tabs::-webkit-scrollbar { display: none; }
  .role-tab { flex: 0 0 40px; height: 44px; border-radius: 8px; }
  .role-tab span { font-size: 9px; padding: 4px 0; }
  .estimate-card { min-height: 188px; margin-top: 22px; padding: 20px 16px; }
  .card-pointer { left: 13px; }
  .estimate-card h3 { line-height: 1.55; }
  .person-line p { font-size: 12px; }
  .estimate-card small { margin-top: 15px; line-height: 1.5; }
  .closing-section { padding: 60px 20px 66px; }
  .closing-section h2 { font-size: 27px; }
  footer { flex-direction: column; gap: 16px; text-align: center; }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { scroll-behavior: auto !important; transition: none !important; }
}