:root {
  --bg: #f6f7fb;
  --surface: rgba(255, 255, 255, .86);
  --surface-strong: #ffffff;
  --text: #151821;
  --muted: #646b7a;
  --line: #e4e7ee;
  --accent: #635bff;
  --accent-soft: #ecebff;
  --shadow: 0 18px 55px rgba(25, 29, 45, .08);
  --max: 960px;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0b0d12;
    --surface: rgba(20, 23, 31, .88);
    --surface-strong: #14171f;
    --text: #f3f5fb;
    --muted: #a8afbf;
    --line: #282d39;
    --accent: #9b96ff;
    --accent-soft: #252345;
    --shadow: 0 18px 55px rgba(0, 0, 0, .24);
  }
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: ui-sans-serif, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  background:
    radial-gradient(circle at 15% 0%, color-mix(in srgb, var(--accent) 12%, transparent), transparent 35rem),
    var(--bg);
  color: var(--text);
  line-height: 1.65;
}

a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }

.site-header {
  position: sticky;
  top: 0;
  z-index: 10;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: .9rem max(1rem, calc((100vw - var(--max)) / 2));
  background: color-mix(in srgb, var(--bg) 82%, transparent);
  backdrop-filter: blur(18px);
  border-bottom: 1px solid color-mix(in srgb, var(--line) 80%, transparent);
}

.brand { display: inline-flex; align-items: center; gap: .6rem; color: var(--text); font-weight: 750; }
.brand:hover { text-decoration: none; }
.brand-mark { display: grid; place-items: center; width: 2rem; height: 2rem; background: var(--accent-soft); border-radius: .7rem; }
nav { display: flex; gap: 1.1rem; }
nav a { color: var(--muted); font-size: .92rem; }

main { width: min(var(--max), calc(100% - 2rem)); margin: 0 auto; }
.hero { padding: 5.5rem 0 2.2rem; max-width: 790px; }
.eyebrow { color: var(--accent); font-weight: 750; letter-spacing: .08em; text-transform: uppercase; font-size: .78rem; }
h1 { margin: .35rem 0 1rem; font-size: clamp(2.7rem, 8vw, 5.8rem); line-height: .96; letter-spacing: -.055em; }
.lead { font-size: clamp(1.05rem, 2vw, 1.32rem); color: var(--muted); max-width: 750px; }
.meta { margin-top: 1.5rem; color: var(--muted); font-size: .92rem; }

.summary {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1rem;
  margin: .5rem 0 1.2rem;
}
.summary article,
.card {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: 1.25rem;
  box-shadow: var(--shadow);
  backdrop-filter: blur(16px);
}
.summary article { padding: 1.15rem; }
.summary strong, .summary span { display: block; }
.summary strong { margin-bottom: .3rem; }
.summary span { color: var(--muted); font-size: .93rem; }

.card { padding: clamp(1.25rem, 4vw, 3rem); margin-bottom: 3rem; }
.prose h2 { margin: 2.15rem 0 .6rem; font-size: 1.35rem; letter-spacing: -.02em; }
.prose h2:first-child { margin-top: 0; }
.prose p, .prose li { color: color-mix(in srgb, var(--text) 84%, var(--muted)); }
.prose ul { padding-left: 1.2rem; }
.notice { padding: 1rem 1.1rem; background: var(--accent-soft); border-radius: .9rem; }

footer {
  width: min(var(--max), calc(100% - 2rem));
  margin: 0 auto;
  padding: 0 0 3rem;
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  color: var(--muted);
  font-size: .92rem;
}

@media (max-width: 720px) {
  .site-header { align-items: flex-start; }
  nav { display: none; }
  .hero { padding-top: 3.2rem; }
  .summary { grid-template-columns: 1fr; }
  footer { flex-direction: column; }
}