:root {
  color-scheme: light;
  --ink: #132235;
  --muted: #5b6b7d;
  --line: #dce5ea;
  --soft: #f4f8f9;
  --blue: #0f5f9f;
  --cyan: #1aa1ad;
  --danger: #a93636;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  background: #fff;
  color: var(--ink);
  font: 16px/1.72 -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto,
    "Noto Sans", "Noto Sans SC", "Helvetica Neue", Arial, sans-serif;
}

a { color: var(--blue); }

.site-header {
  position: sticky;
  top: 0;
  z-index: 5;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  min-height: 68px;
  padding: 10px max(20px, calc((100vw - 1040px) / 2));
  border-bottom: 1px solid rgba(220, 229, 234, .92);
  background: rgba(255, 255, 255, .96);
  backdrop-filter: blur(14px);
}

.brand {
  display: flex;
  align-items: center;
  gap: 12px;
  color: var(--ink);
  text-decoration: none;
}

.brand-mark {
  display: grid;
  width: 42px;
  height: 42px;
  place-items: center;
  border-radius: 13px;
  background: linear-gradient(135deg, #0d1623, var(--blue) 52%, var(--cyan));
  color: #fff;
  font-weight: 800;
  letter-spacing: -.06em;
}

.brand span:last-child { display: grid; line-height: 1.2; }
.brand small { margin-top: 3px; color: var(--muted); }
.header-links { display: flex; flex-wrap: wrap; gap: 14px; }

.page {
  width: min(920px, calc(100% - 40px));
  margin: 48px auto 80px;
}

.hero {
  padding: 38px;
  border: 1px solid var(--line);
  border-radius: 24px;
  background:
    radial-gradient(circle at 90% 10%, rgba(26, 161, 173, .14), transparent 38%),
    linear-gradient(135deg, #f9fbfc, var(--soft));
}

.eyebrow {
  margin: 0 0 8px;
  color: var(--blue);
  font-size: 13px;
  font-weight: 750;
  letter-spacing: .1em;
  text-transform: uppercase;
}

h1 { margin: 0; font-size: clamp(30px, 5vw, 48px); line-height: 1.18; }
.subtitle { margin: 10px 0 0; color: var(--muted); font-size: 18px; }
.meta { margin: 18px 0 0; color: var(--muted); font-size: 14px; }

.notice {
  margin: 24px 0;
  padding: 16px 18px;
  border-left: 4px solid var(--cyan);
  border-radius: 10px;
  background: var(--soft);
}

.toc {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 8px 20px;
  margin: 28px 0;
  padding: 22px 26px;
  border: 1px solid var(--line);
  border-radius: 18px;
}

.toc a { text-decoration: none; }

section { padding: 24px 0; border-bottom: 1px solid var(--line); }
h2 { margin: 0 0 12px; font-size: 24px; line-height: 1.3; }
h3 { margin: 20px 0 8px; font-size: 18px; }
p { margin: 10px 0; }
ul, ol { padding-left: 24px; }
li + li { margin-top: 7px; }

.summary-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 14px;
}

.summary-card {
  padding: 18px;
  border: 1px solid var(--line);
  border-radius: 16px;
  background: #fff;
}

.summary-card strong { display: block; margin-bottom: 6px; }

.button {
  display: inline-block;
  margin: 8px 8px 8px 0;
  padding: 11px 18px;
  border-radius: 999px;
  background: var(--blue);
  color: #fff;
  font-weight: 700;
  text-decoration: none;
}

.button.secondary { background: var(--soft); color: var(--blue); }

.site-footer {
  padding: 28px 20px 42px;
  background: #0d1623;
  color: #d8e6ef;
  text-align: center;
}

.site-footer a { color: #9bdfe7; }
.lang-note { color: var(--muted); font-size: 14px; }

@media (max-width: 640px) {
  .site-header { align-items: flex-start; }
  .header-links { justify-content: flex-end; font-size: 14px; }
  .page { width: min(100% - 28px, 920px); margin-top: 22px; }
  .hero { padding: 24px; border-radius: 18px; }
  .toc, .summary-grid { grid-template-columns: 1fr; }
  .toc { padding: 18px; }
}