:root {
  color-scheme: light dark;
  --bg: #f7f8fb;
  --surface: rgba(255, 255, 255, 0.88);
  --text: #16181d;
  --muted: #656b76;
  --line: rgba(22, 24, 29, 0.1);
  --blue: #1769ff;
  --cyan: #00a6c7;
  --violet: #7b55e7;
  --shadow: 0 18px 55px rgba(25, 35, 55, 0.08);
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  min-height: 100vh;
  font-family: -apple-system, BlinkMacSystemFont, "SF Pro Text", "PingFang SC", "Helvetica Neue", Arial, sans-serif;
  font-size: 16px;
  line-height: 1.72;
  color: var(--text);
  background:
    radial-gradient(circle at 7% 0%, rgba(23, 105, 255, 0.12), transparent 28rem),
    radial-gradient(circle at 92% 18%, rgba(123, 85, 231, 0.12), transparent 26rem),
    var(--bg);
}

a {
  color: var(--blue);
  text-underline-offset: 0.18em;
}

.site-header,
.site-footer,
.shell {
  width: min(100% - 32px, 900px);
  margin-inline: auto;
}

.site-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  padding: 24px 0;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  color: var(--text);
  font-weight: 700;
  text-decoration: none;
  letter-spacing: -0.02em;
}

.brand-mark {
  width: 30px;
  height: 30px;
  border: 2px solid var(--blue);
  border-radius: 50%;
  position: relative;
}

.brand-mark::before,
.brand-mark::after {
  content: "";
  position: absolute;
  inset: 5px;
  border: 2px solid var(--violet);
  border-radius: 50%;
}

.brand-mark::after {
  inset: 11px;
  border-color: var(--cyan);
}

.nav {
  display: flex;
  flex-wrap: wrap;
  justify-content: flex-end;
  gap: 8px 16px;
  font-size: 14px;
}

.nav a {
  color: var(--muted);
  text-decoration: none;
}

.nav a:hover,
.nav a:focus-visible {
  color: var(--blue);
}

.hero,
.document {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: 28px;
  box-shadow: var(--shadow);
  backdrop-filter: blur(18px);
}

.hero {
  padding: clamp(36px, 8vw, 76px);
  overflow: hidden;
  position: relative;
}

.eyebrow {
  margin: 0 0 8px;
  color: var(--blue);
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
}

h1,
h2,
h3 {
  line-height: 1.25;
}

h1 {
  margin: 0;
  max-width: 720px;
  font-size: clamp(34px, 7vw, 64px);
  letter-spacing: -0.05em;
}

.lead {
  max-width: 660px;
  margin: 18px 0 0;
  color: var(--muted);
  font-size: clamp(17px, 2.3vw, 20px);
}

.cards {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 16px;
  margin-top: 24px;
}

.card {
  display: block;
  min-height: 180px;
  padding: 24px;
  color: var(--text);
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: 22px;
  text-decoration: none;
  box-shadow: 0 10px 30px rgba(25, 35, 55, 0.05);
  transition: transform 180ms ease, border-color 180ms ease, box-shadow 180ms ease;
}

.card:hover,
.card:focus-visible {
  transform: translateY(-3px);
  border-color: rgba(23, 105, 255, 0.45);
  box-shadow: 0 16px 38px rgba(25, 35, 55, 0.1);
}

.card h2 {
  margin: 10px 0 8px;
  font-size: 22px;
}

.card p {
  margin: 0;
  color: var(--muted);
}

.card-index {
  color: var(--blue);
  font-size: 13px;
  font-weight: 700;
}

.document {
  padding: clamp(28px, 6vw, 58px);
}

.document h1 {
  font-size: clamp(32px, 5vw, 48px);
}

.document h2 {
  margin: 36px 0 12px;
  font-size: 24px;
}

.document h3 {
  margin: 24px 0 8px;
  font-size: 18px;
}

.document p,
.document li {
  color: #343942;
}

.document ul,
.document ol {
  padding-left: 1.35em;
}

.meta,
.note {
  color: var(--muted);
}

.language-links {
  display: flex;
  gap: 10px;
  margin: 22px 0 0;
}

.language-links a {
  padding: 6px 12px;
  border: 1px solid var(--line);
  border-radius: 999px;
  text-decoration: none;
  font-size: 14px;
}

.language-section + .language-section {
  margin-top: 54px;
  padding-top: 46px;
  border-top: 1px solid var(--line);
}

.contact-box {
  margin-top: 38px;
  padding: 22px 24px;
  background: rgba(23, 105, 255, 0.07);
  border: 1px solid rgba(23, 105, 255, 0.18);
  border-radius: 18px;
}

.contact-box h2,
.contact-box h3,
.contact-box p {
  margin-top: 0;
}

.site-footer {
  padding: 30px 0 40px;
  color: var(--muted);
  font-size: 14px;
  text-align: center;
}

.site-footer a {
  color: inherit;
}

@media (max-width: 720px) {
  .site-header {
    align-items: flex-start;
    flex-direction: column;
  }

  .nav {
    justify-content: flex-start;
  }

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

  .card {
    min-height: 0;
  }
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0d0f13;
    --surface: rgba(24, 27, 34, 0.88);
    --text: #f4f6fb;
    --muted: #aab0bc;
    --line: rgba(255, 255, 255, 0.1);
    --blue: #78a7ff;
    --cyan: #57d3e9;
    --violet: #ae91ff;
    --shadow: 0 18px 55px rgba(0, 0, 0, 0.28);
  }

  .document p,
  .document li {
    color: #d6dae3;
  }
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  .card {
    transition: none;
  }
}