:root {
  color-scheme: dark;
  --ink: #f5f5f2;
  --body: #d1d1cd;
  --muted: #969691;
  --paper: #050505;
  --panel: #101010;
  --panel-raised: #151515;
  --line: #292929;
  --line-strong: #626262;
  --white: #ffffff;
  --max: 1120px;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  color: var(--ink);
  background:
    radial-gradient(circle at 82% -16%, #1a1a1a 0, transparent 34rem),
    var(--paper);
  font-family: ui-sans-serif, -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  line-height: 1.7;
  text-rendering: optimizeLegibility;
}

img { max-width: 100%; }

a {
  color: inherit;
  text-underline-offset: 0.22em;
}

a:focus-visible,
button:focus-visible {
  outline: 2px solid var(--white);
  outline-offset: 4px;
}

.skip-link {
  position: fixed;
  top: 12px;
  left: 16px;
  z-index: 20;
  transform: translateY(-140%);
  padding: 8px 12px;
  border: 1px solid var(--white);
  border-radius: 999px;
  background: var(--white);
  color: #000;
  text-decoration: none;
  transition: transform 160ms ease;
}

.skip-link:focus { transform: translateY(0); }

.shell {
  width: min(var(--max), calc(100% - 48px));
  margin: 0 auto;
}

.site-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 28px;
  padding: 24px 0;
  border-bottom: 1px solid var(--line);
}

.mark {
  display: inline-flex;
  flex: 0 0 auto;
  align-items: center;
  min-width: 0;
  text-decoration: none;
}

.brand-logo {
  display: block;
  width: clamp(168px, 18vw, 238px);
  height: auto;
  filter: invert(1);
  mix-blend-mode: screen;
}

.nav {
  display: flex;
  flex-wrap: wrap;
  justify-content: flex-end;
  gap: 8px 22px;
  color: var(--muted);
  font-size: 0.84rem;
  letter-spacing: 0.03em;
}

.nav a {
  text-decoration: none;
  transition: color 160ms ease;
}

.nav a:hover { color: var(--ink); }

.hero {
  max-width: 980px;
  padding: clamp(94px, 15vw, 180px) 0 clamp(104px, 13vw, 156px);
}

.eyebrow {
  margin: 0;
  color: var(--muted);
  font-size: 0.7rem;
  font-weight: 700;
  letter-spacing: 0.22em;
  text-transform: uppercase;
}

h1,
h2,
h3 {
  color: var(--ink);
  line-height: 1.08;
  letter-spacing: -0.045em;
}

h1 {
  max-width: 900px;
  margin: 22px 0 26px;
  font-size: clamp(3rem, 8vw, 7rem);
  font-weight: 670;
}

h2 {
  margin: 10px 0 0;
  font-size: clamp(2rem, 4.6vw, 4rem);
  font-weight: 650;
}

h3 {
  margin: 26px 0 10px;
  font-size: 1.28rem;
}

.lede {
  max-width: 720px;
  margin: 0;
  color: var(--body);
  font-size: clamp(1.08rem, 1.8vw, 1.25rem);
}

.hero-actions,
.inline-actions,
.panel-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.hero-actions { margin-top: 34px; }

.hero-note {
  max-width: 760px;
  margin: 24px 0 0;
  color: var(--muted);
  font-size: 0.88rem;
}

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  padding: 10px 17px;
  border: 1px solid var(--line-strong);
  border-radius: 999px;
  background: transparent;
  color: var(--ink);
  text-decoration: none;
  font-size: 0.88rem;
  line-height: 1.35;
  transition: border-color 160ms ease, background-color 160ms ease, color 160ms ease;
}

.button:hover {
  border-color: var(--white);
  background: var(--white);
  color: #000;
}

.button.primary {
  border-color: var(--white);
  background: var(--white);
  color: #000;
}

.button.primary:hover {
  border-color: #d0d0cc;
  background: #d0d0cc;
}

.button.quiet { color: var(--muted); }

.section {
  padding: clamp(58px, 8vw, 100px) 0;
  border-top: 1px solid var(--line);
}

.section-heading {
  display: grid;
  grid-template-columns: minmax(0, 0.95fr) minmax(280px, 0.7fr);
  gap: 22px 60px;
  align-items: end;
  margin-bottom: 28px;
}

.section-heading .eyebrow {
  grid-column: 1 / -1;
}

.section-heading p:not(.eyebrow) {
  margin: 0;
  color: var(--muted);
}

.feature-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 12px;
}

.card {
  min-height: 228px;
  padding: 24px;
  border: 1px solid var(--line);
  background: var(--panel);
  transition: border-color 160ms ease, background-color 160ms ease;
}

.card:hover {
  border-color: var(--line-strong);
  background: var(--panel-raised);
}

.card p {
  margin: 0;
  color: var(--body);
  font-size: 0.94rem;
}

.card-label {
  color: var(--muted);
  font-size: 0.7rem;
  font-weight: 700;
  letter-spacing: 0.18em;
}

.split-section {
  display: grid;
  grid-template-columns: minmax(0, 0.72fr) minmax(320px, 1fr);
  gap: 28px 74px;
  align-items: start;
}

.steps {
  display: grid;
  gap: 0;
}

.step {
  display: grid;
  grid-template-columns: 48px 1fr;
  gap: 18px;
  align-items: baseline;
  padding: 20px 0;
  border-bottom: 1px solid var(--line);
}

.step:first-child { padding-top: 4px; }

.step p {
  margin: 0;
  color: var(--body);
}

.step-number {
  color: var(--muted);
  font-size: 0.72rem;
  font-weight: 800;
  letter-spacing: 0.14em;
}

.support-panel {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  margin-bottom: 48px;
  padding: 28px;
  border: 1px solid var(--line-strong);
  background: var(--panel);
}

.support-panel h2 {
  max-width: 620px;
  margin-top: 8px;
  font-size: clamp(1.75rem, 3.6vw, 3rem);
}

.support-panel p:not(.eyebrow) {
  max-width: 620px;
  margin: 12px 0 0;
  color: var(--muted);
}

.panel-actions {
  flex: 0 0 auto;
  justify-content: flex-end;
}

.site-footer {
  padding: 30px 0 38px;
  border-top: 1px solid var(--line);
  color: var(--muted);
  font-size: 0.8rem;
}

.footer-row {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 14px 22px;
}

.footer-links {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 18px;
}

.footer-links a {
  text-decoration-thickness: 1px;
}

.document {
  max-width: 790px;
  padding: 78px 0 110px;
}

.document h1 {
  margin-bottom: 12px;
  font-size: clamp(2.65rem, 6.6vw, 5rem);
}

.document .updated {
  color: var(--muted);
  font-size: 0.86rem;
}

.document h2 {
  margin-top: 52px;
  font-size: 1.5rem;
}

.document h3 {
  margin-top: 30px;
  font-size: 1.08rem;
}

.document p,
.document li {
  color: var(--body);
}

.document ul { padding-left: 1.3em; }

.notice {
  padding: 20px 22px;
  border-left: 2px solid var(--white);
  background: var(--panel);
}

.document a:not(.button) {
  color: var(--white);
}

.inline-actions { margin-top: 18px; }

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    scroll-behavior: auto !important;
    transition-duration: 0.01ms !important;
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
  }
}

@media (max-width: 860px) {
  .section-heading,
  .split-section {
    grid-template-columns: 1fr;
  }

  .feature-grid { grid-template-columns: 1fr; }

  .support-panel { display: block; }

  .panel-actions {
    justify-content: flex-start;
    margin-top: 20px;
  }
}

@media (max-width: 720px) {
  .shell { width: min(var(--max), calc(100% - 32px)); }

  .site-header {
    align-items: flex-start;
    padding-top: 18px;
  }

  .brand-logo { width: 182px; }

  .nav {
    gap: 7px 14px;
    font-size: 0.78rem;
  }

  .hero {
    padding-top: 82px;
  }

  .card { min-height: auto; }
}

@media (max-width: 430px) {
  .site-header { display: block; }

  .brand-logo { width: 174px; }

  .nav {
    justify-content: flex-start;
    margin-top: 18px;
  }

  h1 {
    font-size: clamp(2.8rem, 15vw, 4.2rem);
  }

  .button { width: 100%; }

  .step {
    grid-template-columns: 1fr;
    gap: 4px;
  }

  .support-panel { padding: 22px; }
}