:root {
  --bg: #f7f8fb;
  --paper: #ffffff;
  --ink: #111827;
  --muted: #5f6b7a;
  --line: #e3e7ee;
  --soft: #eef2f7;
  --blue: #245eea;
  --blue-dark: #1647c8;
  --orange: #d97706;
  --green: #1f8a5b;
  --shadow: 0 20px 60px rgba(17, 24, 39, .08);
  --radius: 22px;
  --content: 1160px;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  color: var(--ink);
  background:
    radial-gradient(circle at 50% -10%, rgba(36, 94, 234, .07), transparent 28rem),
    var(--bg);
  font-family: Inter, ui-sans-serif, -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  line-height: 1.65;
  text-rendering: optimizeLegibility;
}

a { color: inherit; text-decoration: none; }
img { display: block; max-width: 100%; }
code, pre { font-family: "SFMono-Regular", Consolas, "Liberation Mono", monospace; }

.site-header {
  position: sticky;
  top: 0;
  z-index: 20;
  border-bottom: 1px solid rgba(227, 231, 238, .85);
  background: rgba(247, 248, 251, .86);
  backdrop-filter: blur(18px);
}
.nav-wrap {
  max-width: var(--content);
  height: 68px;
  margin: 0 auto;
  padding: 0 24px;
  display: flex;
  align-items: center;
  gap: 28px;
}
.brand { display: inline-flex; align-items: center; gap: 10px; font-weight: 750; letter-spacing: -.02em; }
.brand-mark {
  width: 32px;
  height: 32px;
  display: grid;
  place-items: center;
  border-radius: 9px;
  background: var(--ink);
  color: #fff;
  font-size: 12px;
  letter-spacing: -.04em;
}
.nav-links { margin-left: auto; display: flex; gap: 28px; color: #4b5563; font-size: 14px; }
.nav-links a:hover { color: var(--ink); }
.nav-github {
  border: 1px solid var(--line);
  border-radius: 999px;
  padding: 8px 14px;
  background: #fff;
  font-size: 14px;
  font-weight: 650;
}

.section {
  max-width: var(--content);
  margin: 0 auto;
  padding: 96px 24px;
}
.section.compact { padding-top: 56px; }
.hero {
  min-height: calc(100vh - 68px);
  display: grid;
  grid-template-columns: .93fr 1.07fr;
  align-items: center;
  gap: 50px;
  padding-top: 72px;
  padding-bottom: 80px;
}
.eyebrow-row { display: flex; flex-wrap: wrap; gap: 8px; margin-bottom: 20px; }
.pill {
  border: 1px solid #d8deea;
  background: rgba(255,255,255,.82);
  padding: 6px 10px;
  border-radius: 999px;
  color: #485569;
  font-size: 12px;
  font-weight: 700;
  letter-spacing: .03em;
}
.hero h1 {
  margin: 0;
  font-size: clamp(58px, 7.4vw, 100px);
  line-height: .92;
  letter-spacing: -.072em;
  font-weight: 830;
}
.hero-tagline {
  max-width: 650px;
  margin: 26px 0 0;
  font-size: clamp(22px, 2.2vw, 34px);
  line-height: 1.22;
  letter-spacing: -.035em;
  font-weight: 690;
}
.hero-cn { max-width: 650px; margin: 18px 0 0; font-size: 16px; color: var(--muted); }
.hero-actions { display: flex; flex-wrap: wrap; gap: 10px; margin-top: 28px; }
.button {
  min-height: 44px;
  padding: 10px 18px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border-radius: 11px;
  font-size: 14px;
  font-weight: 700;
  transition: transform .18s ease, box-shadow .18s ease, background .18s ease;
}
.button:hover { transform: translateY(-1px); }
.button.primary { background: var(--ink); color: #fff; box-shadow: 0 10px 24px rgba(17,24,39,.14); }
.button.primary:hover { background: #000; }
.button.secondary { background: #fff; border: 1px solid var(--line); }
.button.ghost { color: var(--blue); }
.hero-visual {
  border: 1px solid var(--line);
  border-radius: 28px;
  padding: 10px;
  background: rgba(255,255,255,.84);
  box-shadow: var(--shadow);
  transform: rotate(.8deg);
}
.hero-visual img { width: 100%; border-radius: 19px; }

.kicker {
  display: inline-block;
  color: var(--blue);
  text-transform: uppercase;
  letter-spacing: .12em;
  font-size: 12px;
  font-weight: 800;
  margin-bottom: 12px;
}
.section-heading { max-width: 820px; }
.section-heading.centered { margin: 0 auto 42px; text-align: center; }
.section-heading h2,
.split-copy h2,
.tech-copy h2,
.boundary-section h2,
.cta h2 {
  margin: 0;
  font-size: clamp(34px, 4vw, 54px);
  line-height: 1.08;
  letter-spacing: -.045em;
}
.section-heading p,
.split-copy > p,
.tech-copy > p,
.boundary-section > p {
  margin: 20px 0 0;
  color: var(--muted);
  font-size: 17px;
}

.metrics {
  margin-top: 38px;
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}
.metric { padding: 24px 22px; border-right: 1px solid var(--line); }
.metric:first-child { padding-left: 0; }
.metric:last-child { border-right: 0; }
.metric-value { display: block; font-size: 21px; font-weight: 800; letter-spacing: -.02em; }
.metric-label { display: block; margin-top: 4px; color: #7a8492; font-size: 12px; line-height: 1.45; }

.figure-card {
  padding: 22px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--paper);
  box-shadow: var(--shadow);
}
.figure-card img { width: 100%; }
.three-principles {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 18px;
  margin-top: 20px;
}
.three-principles article {
  padding: 26px;
  border: 1px solid var(--line);
  border-radius: 18px;
  background: rgba(255,255,255,.7);
}
.principle-index { color: #9ba5b2; font-size: 12px; font-weight: 800; letter-spacing: .1em; }
.three-principles h3 { margin: 10px 0 8px; font-size: 19px; }
.three-principles p { margin: 0; color: var(--muted); font-size: 14px; }

.split-section {
  display: grid;
  grid-template-columns: .9fr 1.1fr;
  gap: 72px;
  align-items: center;
}
.mini-flow { display: flex; flex-wrap: wrap; gap: 9px; align-items: center; margin-top: 26px; font-size: 13px; }
.mini-flow span { padding: 7px 10px; border-radius: 8px; border: 1px solid var(--line); background: #fff; }
.mini-flow .accent-box { border-color: #abc2ff; color: var(--blue-dark); background: #eef3ff; font-weight: 800; }
.decision-panels { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; }
.decision-card {
  min-height: 330px;
  padding: 28px;
  border-radius: 22px;
  color: #fff;
  box-shadow: var(--shadow);
}
.decision-card.slow { background: linear-gradient(160deg, #202b48, #111827); }
.decision-card.fast { background: linear-gradient(160deg, #164e63, #0d2f3a); }
.decision-label { font-size: 11px; font-weight: 850; letter-spacing: .12em; opacity: .64; }
.decision-card h3 { margin: 14px 0 22px; font-size: 26px; letter-spacing: -.03em; }
.decision-card ul { margin: 0; padding-left: 18px; color: rgba(255,255,255,.82); }
.decision-card li { margin: 12px 0; }

.gallery {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 18px;
}
.shot {
  margin: 0;
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: 20px;
  background: var(--paper);
  box-shadow: 0 14px 44px rgba(17,24,39,.06);
}
.shot.wide { grid-column: 1 / -1; }
.shot img { width: 100%; display: block; background: #eef1f6; }
.shot:not(.strip-shot) img { aspect-ratio: 16 / 10; object-fit: cover; object-position: top center; }
.strip-shot img { object-fit: contain; background: #11151b; }
.shot figcaption { padding: 18px 20px 20px; display: flex; gap: 8px; flex-direction: column; }
.shot figcaption b { font-size: 15px; }
.shot figcaption span { color: var(--muted); font-size: 13px; }

.feature-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px; margin-top: 38px; }
.feature-card {
  padding: 26px;
  border: 1px solid var(--line);
  border-radius: 18px;
  background: rgba(255,255,255,.78);
}
.feature-icon { width: 36px; height: 36px; display: grid; place-items: center; border-radius: 10px; background: #edf2ff; color: var(--blue); font-weight: 900; }
.feature-card h3 { margin: 18px 0 9px; font-size: 18px; }
.feature-card p { margin: 0; color: var(--muted); font-size: 14px; }

.tech-section { display: grid; grid-template-columns: 1fr .9fr; gap: 64px; align-items: center; }
.tech-tags { margin-top: 24px; display: flex; flex-wrap: wrap; gap: 8px; }
.tech-tags span { border: 1px solid var(--line); background: #fff; border-radius: 999px; padding: 6px 10px; font-size: 12px; color: #536071; }
.code-card { overflow: hidden; border-radius: 18px; background: #111827; color: #dbe5f3; box-shadow: var(--shadow); }
.code-card pre { margin: 0; padding: 28px; overflow: auto; font-size: 13px; line-height: 1.7; }

.boundary-section {
  display: grid;
  grid-template-columns: .8fr 1.2fr;
  gap: 60px;
  padding-top: 62px;
  padding-bottom: 62px;
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}
.boundary-section h2 { font-size: clamp(30px, 3.2vw, 44px); }
.boundary-section > p { margin-top: 28px; }

.cta { text-align: center; padding-top: 112px; padding-bottom: 112px; }
.cta h2 { max-width: 720px; margin: 0 auto; }
.centered-actions { justify-content: center; }

.footer {
  max-width: var(--content);
  margin: 0 auto;
  padding: 34px 24px 46px;
  border-top: 1px solid var(--line);
  display: flex;
  justify-content: space-between;
  gap: 30px;
  color: #6b7280;
  font-size: 12px;
}
.footer-note { max-width: 600px; text-align: right; }

.reveal {
  opacity: 0;
  transform: translateY(12px);
  transition: opacity .55s ease, transform .55s ease;
}
.reveal.visible { opacity: 1; transform: none; }

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

@media (max-width: 980px) {
  .nav-links { display: none; }
  .nav-github { margin-left: auto; }
  .hero { grid-template-columns: 1fr; min-height: auto; padding-top: 62px; }
  .hero-copy { max-width: 820px; }
  .hero-visual { transform: none; }
  .metrics { grid-template-columns: 1fr 1fr; }
  .metric:nth-child(2) { border-right: 0; }
  .metric:nth-child(-n+2) { border-bottom: 1px solid var(--line); }
  .metric:first-child, .metric:nth-child(3) { padding-left: 0; }
  .three-principles { grid-template-columns: 1fr; }
  .split-section, .tech-section, .boundary-section { grid-template-columns: 1fr; gap: 34px; }
}

@media (max-width: 720px) {
  .section { padding: 72px 18px; }
  .nav-wrap { padding: 0 18px; }
  .hero { padding-top: 50px; }
  .hero h1 { font-size: clamp(54px, 19vw, 84px); }
  .hero-tagline { font-size: 24px; }
  .metrics { grid-template-columns: 1fr; }
  .metric { border-right: 0; border-bottom: 1px solid var(--line); padding-left: 0; }
  .metric:last-child { border-bottom: 0; }
  .decision-panels, .feature-grid, .gallery { grid-template-columns: 1fr; }
  .shot.wide { grid-column: auto; }
  .footer { flex-direction: column; }
  .footer-note { text-align: left; }
}