:root {
  color-scheme: dark;
  --bg: #061524;
  --bg-2: #0a2238;
  --surface: rgba(255, 255, 255, 0.075);
  --surface-strong: rgba(255, 255, 255, 0.12);
  --line: rgba(255, 255, 255, 0.15);
  --text: #f3f7fb;
  --muted: #b9c8d8;
  --soft: #8ea6bb;
  --accent: #51a7ff;
  --accent-2: #8ed8ff;
  --warning: #ffd27a;
  --danger: #ff8f8f;
  --shadow: rgba(0, 0, 0, 0.32);
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  min-width: 320px;
  background:
    radial-gradient(circle at top left, rgba(81, 167, 255, 0.24), transparent 34rem),
    linear-gradient(180deg, var(--bg-2), var(--bg) 36rem, #04101d);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  font-size: 16px;
  line-height: 1.6;
}

a { color: var(--accent-2); text-decoration-thickness: 0.08em; text-underline-offset: 0.18em; }
a:hover { color: #ffffff; }

.skip-link {
  position: absolute;
  left: 1rem;
  top: -4rem;
  z-index: 100;
  padding: 0.7rem 1rem;
  border-radius: 0.5rem;
  background: #ffffff;
  color: #061524;
  font-weight: 700;
}
.skip-link:focus { top: 1rem; }

.site-header {
  position: sticky;
  top: 0;
  z-index: 20;
  border-bottom: 1px solid var(--line);
  background: rgba(6, 21, 36, 0.94);
  backdrop-filter: blur(14px);
}

.header-inner {
  max-width: 1120px;
  margin: 0 auto;
  padding: 0.95rem 1.15rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.7rem;
  color: var(--text);
  font-weight: 800;
  letter-spacing: 0;
  text-decoration: none;
}

.brand-mark {
  width: 2.2rem;
  height: 2.2rem;
  border-radius: 0.55rem;
  display: grid;
  place-items: center;
  background: linear-gradient(135deg, #1670c8, #51a7ff);
  color: #fff;
  box-shadow: 0 0.6rem 1.6rem var(--shadow);
}

.site-nav {
  display: flex;
  flex-wrap: wrap;
  justify-content: flex-end;
  gap: 0.45rem 0.75rem;
  font-size: 0.92rem;
}

.site-nav a {
  color: var(--muted);
  text-decoration: none;
  padding: 0.25rem 0.15rem;
}
.site-nav a:hover, .site-nav a[aria-current="page"] { color: var(--text); }

main {
  max-width: 1120px;
  margin: 0 auto;
  padding: 3.4rem 1.15rem 4rem;
}

.hero {
  min-height: 68vh;
  display: grid;
  align-items: center;
  gap: 2rem;
  padding: 1rem 0 3rem;
}

.hero-grid {
  display: grid;
  grid-template-columns: minmax(0, 1.2fr) minmax(280px, 0.8fr);
  gap: 1.4rem;
  align-items: stretch;
}

.eyebrow {
  margin: 0 0 0.7rem;
  color: var(--accent-2);
  font-size: 0.82rem;
  font-weight: 800;
  letter-spacing: 0.09em;
  text-transform: uppercase;
}

h1, h2, h3 { line-height: 1.15; letter-spacing: 0; }
h1 {
  margin: 0;
  max-width: 14ch;
  font-size: clamp(3.2rem, 11vw, 7.4rem);
  font-weight: 900;
}

.page-title h1 {
  max-width: 900px;
  font-size: clamp(2.4rem, 7vw, 4.6rem);
}

h2 { margin: 0 0 1rem; font-size: clamp(1.45rem, 3vw, 2.15rem); }
h3 { margin: 0 0 0.55rem; font-size: 1.08rem; }
p { margin: 0 0 1rem; color: var(--muted); }
ul, ol { margin: 0.4rem 0 0; padding-left: 1.25rem; color: var(--muted); }
li { margin: 0.35rem 0; }
strong { color: var(--text); }

.lead {
  max-width: 780px;
  color: #d8e5f2;
  font-size: clamp(1.1rem, 2vw, 1.35rem);
}

.actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin-top: 1.4rem;
}

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 2.75rem;
  padding: 0.72rem 1rem;
  border-radius: 0.55rem;
  border: 1px solid var(--line);
  background: rgba(255, 255, 255, 0.08);
  color: var(--text);
  text-decoration: none;
  font-weight: 750;
}
.button.primary { background: linear-gradient(135deg, #1b78d4, #51a7ff); border-color: transparent; color: #fff; }
.button:hover { transform: translateY(-1px); }

.card, .section-card, .notice {
  border: 1px solid var(--line);
  border-radius: 0.9rem;
  background: var(--surface);
  box-shadow: 0 1rem 2.4rem var(--shadow);
}
.card { padding: 1.1rem; }
.section-card { padding: clamp(1.1rem, 3vw, 1.5rem); margin: 1rem 0; }
.notice { padding: 1.15rem; border-color: rgba(255, 210, 122, 0.42); background: rgba(255, 210, 122, 0.10); }
.notice strong { color: var(--warning); }

.hero-panel {
  display: grid;
  gap: 0.75rem;
  align-content: center;
  background:
    linear-gradient(180deg, rgba(81, 167, 255, 0.16), rgba(255,255,255,0.06)),
    var(--surface);
}

.stat-grid, .feature-grid, .link-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 1rem;
}
.feature-grid { grid-template-columns: repeat(4, minmax(0, 1fr)); }
.link-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }

.kicker {
  color: var(--accent-2);
  font-weight: 800;
  font-size: 0.85rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
}

.meta {
  color: var(--soft);
  font-size: 0.98rem;
  margin-top: 0.55rem;
}

.page-title {
  padding-bottom: 1.5rem;
  border-bottom: 1px solid var(--line);
  margin-bottom: 1.4rem;
}

.content-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 280px;
  gap: 1.4rem;
  align-items: start;
}

.toc {
  position: sticky;
  top: 5.5rem;
  padding: 1rem;
}
.toc a { display: block; color: var(--muted); text-decoration: none; padding: 0.25rem 0; }
.toc a:hover { color: var(--text); }

.site-footer {
  border-top: 1px solid var(--line);
  background: rgba(3, 13, 24, 0.75);
}
.footer-inner {
  max-width: 1120px;
  margin: 0 auto;
  padding: 2rem 1.15rem;
  display: grid;
  gap: 1rem;
}
.footer-links { display: flex; flex-wrap: wrap; gap: 0.6rem 1rem; }
.footer-links a { color: var(--muted); text-decoration: none; }
.footer-links a:hover { color: var(--text); }
.small { color: var(--soft); font-size: 0.92rem; }

@media (max-width: 880px) {
  .header-inner { align-items: flex-start; flex-direction: column; }
  .site-nav { justify-content: flex-start; }
  .hero { min-height: auto; }
  .hero-grid, .content-grid { grid-template-columns: 1fr; }
  .feature-grid, .stat-grid, .link-grid { grid-template-columns: 1fr; }
  .toc { position: static; }
}

@media (max-width: 520px) {
  main { padding-top: 2.3rem; }
  .actions { flex-direction: column; }
  .button { width: 100%; }
  .site-nav { font-size: 0.88rem; }
}