:root {
  color-scheme: light;
  --ink: #17203f;
  --muted: #5f6887;
  --line: #dfe4f4;
  --surface: #ffffff;
  --wash: #f5f7ff;
  --brand: #3347b8;
  --brand-dark: #23338f;
  --accent: #e7ebff;
  --max: 74rem;
}

* { box-sizing: border-box; }

html {
  scroll-behavior: smooth;
  background: var(--wash);
}

body {
  margin: 0;
  color: var(--ink);
  background:
    radial-gradient(circle at 88% 2%, rgba(97, 118, 235, .14), transparent 24rem),
    linear-gradient(180deg, #fbfcff 0, var(--wash) 34rem);
  font: 1rem/1.7 ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}

a { color: var(--brand); }
a:hover { color: var(--brand-dark); }
a:focus-visible, .button:focus-visible { outline: 3px solid #f4b942; outline-offset: 3px; }

.skip-link {
  position: fixed;
  left: 1rem;
  top: -5rem;
  z-index: 10;
  padding: .75rem 1rem;
  border-radius: .65rem;
  background: var(--ink);
  color: white;
}
.skip-link:focus { top: 1rem; }

.topbar {
  border-bottom: 1px solid rgba(223, 228, 244, .9);
  background: rgba(255, 255, 255, .88);
  backdrop-filter: blur(14px);
}

.nav {
  width: min(calc(100% - 2rem), var(--max));
  min-height: 4.5rem;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: .7rem;
  color: var(--ink);
  font-weight: 800;
  text-decoration: none;
  letter-spacing: -.02em;
}

.brand-mark {
  display: grid;
  width: 2.2rem;
  height: 2.2rem;
  place-items: center;
  border-radius: .75rem;
  color: white;
  background: linear-gradient(145deg, #6275e9, var(--brand-dark));
  box-shadow: 0 8px 20px rgba(51, 71, 184, .25);
  font-size: 1.05rem;
}

.nav-links { display: flex; align-items: center; gap: .35rem; flex-wrap: wrap; justify-content: flex-end; }
.nav-links a {
  padding: .5rem .7rem;
  border-radius: .6rem;
  color: var(--muted);
  font-size: .92rem;
  font-weight: 650;
  text-decoration: none;
}
.nav-links a:hover, .nav-links a[aria-current="page"] { color: var(--brand-dark); background: var(--accent); }

.hero, .document, .footer-inner {
  width: min(calc(100% - 2rem), var(--max));
  margin-inline: auto;
}

.hero { padding: clamp(3.5rem, 8vw, 7rem) 0 4rem; }
.eyebrow {
  margin: 0 0 .85rem;
  color: var(--brand);
  font-size: .82rem;
  font-weight: 800;
  letter-spacing: .12em;
  text-transform: uppercase;
}
h1, h2, h3 { line-height: 1.2; letter-spacing: -.03em; text-wrap: balance; }
h1 { max-width: 17ch; margin: 0; font-size: clamp(2.7rem, 8vw, 5.6rem); }
.lede { max-width: 44rem; margin: 1.4rem 0 0; color: var(--muted); font-size: clamp(1.05rem, 2vw, 1.25rem); }

.cards {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1rem;
  margin-top: 2.3rem;
}
.card {
  display: block;
  padding: 1.5rem;
  border: 1px solid var(--line);
  border-radius: 1.2rem;
  color: var(--ink);
  background: rgba(255,255,255,.88);
  box-shadow: 0 14px 40px rgba(24, 36, 88, .06);
  text-decoration: none;
  transition: transform .18s ease, border-color .18s ease, box-shadow .18s ease;
}
.card:hover { transform: translateY(-3px); border-color: #aab5ee; box-shadow: 0 18px 44px rgba(24,36,88,.1); }
.card h2 { margin: 0 0 .45rem; font-size: 1.35rem; }
.card p { margin: 0; color: var(--muted); }
.card .arrow { display: block; margin-top: 1.25rem; color: var(--brand); font-weight: 800; }

.document {
  display: grid;
  grid-template-columns: 14rem minmax(0, 1fr);
  gap: clamp(2rem, 5vw, 5rem);
  padding: 3.5rem 0 5rem;
}
.toc { align-self: start; position: sticky; top: 1.5rem; }
.toc strong { display: block; margin-bottom: .7rem; font-size: .85rem; letter-spacing: .08em; text-transform: uppercase; }
.toc a { display: block; padding: .28rem 0; color: var(--muted); font-size: .9rem; text-decoration: none; }
.toc a:hover { color: var(--brand); }
.paper {
  min-width: 0;
  padding: clamp(1.5rem, 5vw, 4.2rem);
  border: 1px solid var(--line);
  border-radius: 1.35rem;
  background: var(--surface);
  box-shadow: 0 20px 60px rgba(24, 36, 88, .08);
}
.paper header { padding-bottom: 2rem; border-bottom: 1px solid var(--line); }
.paper h1 { max-width: none; font-size: clamp(2.2rem, 6vw, 4rem); }
.meta { margin-top: 1rem; color: var(--muted); font-size: .94rem; }
.summary {
  margin: 1.7rem 0 0;
  padding: 1rem 1.1rem;
  border-left: 4px solid var(--brand);
  border-radius: 0 .7rem .7rem 0;
  background: var(--accent);
}
.paper section { padding-top: 2.2rem; scroll-margin-top: 1.5rem; }
.paper h2 { margin: 0 0 .8rem; font-size: 1.5rem; }
.paper h3 { margin: 1.4rem 0 .45rem; font-size: 1.08rem; }
.paper p, .paper ul { max-width: 68ch; }
.paper ul { padding-left: 1.25rem; }
.paper li + li { margin-top: .55rem; }
.table-wrap { overflow-x: auto; margin-top: 1rem; }
table { width: 100%; border-collapse: collapse; font-size: .94rem; }
th, td { padding: .8rem; border: 1px solid var(--line); text-align: left; vertical-align: top; }
th { background: var(--wash); }
.callout { padding: 1rem 1.1rem; border: 1px solid #c9d1f7; border-radius: .8rem; background: #f7f8ff; }
.button {
  display: inline-block;
  margin-top: .6rem;
  padding: .7rem .95rem;
  border-radius: .7rem;
  color: white;
  background: var(--brand);
  font-weight: 750;
  text-decoration: none;
}
.button:hover { color: white; background: var(--brand-dark); }

footer { border-top: 1px solid var(--line); background: white; }
.footer-inner { display: flex; justify-content: space-between; gap: 1rem; padding: 1.5rem 0; color: var(--muted); font-size: .9rem; }
.footer-inner p { margin: 0; }

@media (max-width: 760px) {
  .nav { align-items: flex-start; padding: .8rem 0; }
  .nav-links { gap: 0; }
  .cards { grid-template-columns: 1fr; }
  .document { display: block; padding-top: 1.25rem; }
  .toc { position: static; margin-bottom: 1rem; padding: 1rem; border: 1px solid var(--line); border-radius: .85rem; background: white; }
  .toc a { display: inline-block; margin-right: .8rem; }
  .paper { border-radius: 1rem; }
  .footer-inner { display: block; }
  .footer-inner p + p { margin-top: .35rem; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .card { transition: none; }
}