:root {
  color-scheme: light;
  --ink: #163944;
  --muted: #60757b;
  --line: #dce7e4;
  --soft: #edf5f2;
  --paper: #ffffff;
  --brand: #0f6b5b;
  --brand-dark: #0b5147;
  --shadow: 0 18px 50px rgba(25, 64, 68, 0.08);
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  background:
    radial-gradient(circle at 12% 0%, rgba(45, 145, 118, 0.11), transparent 29rem),
    #f4f7f6;
  color: var(--ink);
  font-family:
    -apple-system, BlinkMacSystemFont, "SF Pro Text", "PingFang SC",
    "Microsoft YaHei", sans-serif;
  line-height: 1.75;
}

a {
  color: var(--brand);
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}

.topbar {
  position: sticky;
  top: 0;
  z-index: 10;
  border-bottom: 1px solid rgba(220, 231, 228, 0.9);
  background: rgba(255, 255, 255, 0.88);
  backdrop-filter: blur(18px);
}

.topbar-inner {
  display: flex;
  width: min(1120px, calc(100% - 40px));
  min-height: 68px;
  margin: 0 auto;
  align-items: center;
  justify-content: space-between;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  color: var(--ink);
  font-size: 19px;
  font-weight: 750;
  letter-spacing: 0.04em;
}

.brand-mark {
  display: grid;
  width: 34px;
  height: 34px;
  place-items: center;
  border-radius: 11px;
  background: var(--brand);
  color: #fff;
  font-size: 18px;
  box-shadow: 0 8px 20px rgba(15, 107, 91, 0.2);
}

.topbar-links {
  display: flex;
  gap: 18px;
  font-size: 14px;
  font-weight: 650;
}

.hero {
  width: min(980px, calc(100% - 40px));
  margin: 72px auto 42px;
  text-align: center;
}

.eyebrow {
  margin: 0 0 12px;
  color: var(--brand);
  font-size: 13px;
  font-weight: 750;
  letter-spacing: 0.16em;
}

h1 {
  margin: 0;
  font-size: clamp(36px, 6vw, 58px);
  line-height: 1.15;
  letter-spacing: -0.045em;
}

.hero > p:last-of-type {
  max-width: 670px;
  margin: 20px auto 0;
  color: var(--muted);
  font-size: 16px;
}

.meta {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 8px 18px;
  margin-top: 24px;
  color: #73868b;
  font-size: 13px;
}

.layout {
  display: grid;
  grid-template-columns: 228px minmax(0, 1fr);
  gap: 28px;
  width: min(1120px, calc(100% - 40px));
  margin: 0 auto 72px;
  align-items: start;
}

.toc {
  position: sticky;
  top: 92px;
  padding: 20px;
  border: 1px solid var(--line);
  border-radius: 18px;
  background: rgba(255, 255, 255, 0.75);
}

.toc strong {
  display: block;
  margin-bottom: 10px;
  font-size: 13px;
}

.toc a {
  display: block;
  padding: 5px 0;
  color: var(--muted);
  font-size: 13px;
}

main {
  min-width: 0;
  padding: clamp(26px, 5vw, 58px);
  border: 1px solid var(--line);
  border-radius: 26px;
  background: var(--paper);
  box-shadow: var(--shadow);
}

.notice {
  margin: 0 0 34px;
  padding: 18px 20px;
  border-left: 4px solid var(--brand);
  border-radius: 0 12px 12px 0;
  background: var(--soft);
  color: #405f63;
  font-size: 14px;
}

section {
  scroll-margin-top: 92px;
}

section + section {
  margin-top: 44px;
  padding-top: 36px;
  border-top: 1px solid var(--line);
}

h2 {
  margin: 0 0 16px;
  font-size: 25px;
  line-height: 1.35;
  letter-spacing: -0.02em;
}

h3 {
  margin: 25px 0 10px;
  font-size: 17px;
}

p,
li {
  color: #425f66;
  font-size: 15px;
}

ul,
ol {
  padding-left: 1.4em;
}

li + li {
  margin-top: 7px;
}

.contact-card {
  display: grid;
  gap: 8px;
  margin-top: 18px;
  padding: 22px;
  border-radius: 16px;
  background: var(--brand-dark);
  color: #fff;
}

.contact-card strong,
.contact-card span,
.contact-card a {
  color: #fff;
}

.contact-card span {
  font-size: 14px;
  opacity: 0.84;
}

footer {
  padding: 0 20px 46px;
  color: #7b8c90;
  text-align: center;
  font-size: 13px;
}

@media (max-width: 820px) {
  .hero {
    margin-top: 48px;
  }

  .layout {
    display: block;
    width: min(100% - 24px, 720px);
  }

  .toc {
    display: none;
  }

  main {
    padding: 26px 20px 36px;
    border-radius: 20px;
  }

  .topbar-links a:first-child {
    display: none;
  }
}

@media print {
  .topbar,
  .toc,
  footer {
    display: none;
  }

  .hero {
    margin: 20px auto;
  }

  .layout {
    display: block;
    width: 100%;
    margin: 0;
  }

  main {
    border: 0;
    box-shadow: none;
  }
}