:root {
  --page-bg: #f4efe5;
  --page-bg-deep: #eae2d5;
  --page-line: rgba(39, 32, 22, 0.15);
  --page-line-strong: rgba(39, 32, 22, 0.28);
  --text-strong: #171411;
  --text-body: #2d271f;
  --text-muted: #675d51;
  --accent: #1f6a55;
  --accent-soft: rgba(31, 106, 85, 0.1);
  --shell-width: 1140px;
  --outer-gap: 36px;
}

*,
*::before,
*::after {
  box-sizing: border-box;
  border-radius: 0;
}

html {
  min-height: 100%;
}

body {
  margin: 0;
  min-height: 100vh;
  color: var(--text-body);
  font-family: "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  background:
    radial-gradient(circle at top right, rgba(255, 255, 255, 0.75), transparent 22%),
    linear-gradient(180deg, rgba(255, 255, 255, 0.34), rgba(255, 255, 255, 0)),
    linear-gradient(180deg, var(--page-bg) 0%, var(--page-bg-deep) 100%);
}

a {
  color: inherit;
  text-decoration: none;
}

.page-shell {
  width: min(calc(100% - (2 * var(--outer-gap))), var(--shell-width));
  margin: 0 auto;
  padding: 26px 0 52px;
}

.site-topline {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  padding: 0 0 18px;
  border-bottom: 1px solid var(--page-line-strong);
}

.brand-mark,
.section-label,
.topic-meta {
  margin: 0;
  letter-spacing: 0.12em;
  text-transform: uppercase;
}

.brand-mark {
  color: var(--text-strong);
  font-size: 13px;
  font-weight: 700;
}

.site-links {
  display: flex;
  flex-wrap: wrap;
  gap: 18px;
}

.site-links a {
  color: var(--text-muted);
  font-size: 13px;
  transition: color 160ms ease, opacity 160ms ease;
}

.site-links a:hover {
  color: var(--text-strong);
  opacity: 0.86;
}

.hero {
  display: grid;
  grid-template-columns: minmax(0, 1.2fr) minmax(260px, 0.8fr);
  gap: 44px;
  align-items: end;
  padding: 62px 0 74px;
  border-bottom: 1px solid var(--page-line-strong);
}

.hero-kicker,
.hero-summary,
.hero-body,
.hero-panel-label,
.hero-panel-text,
.section-title,
.section-summary,
.feature-title,
.feature-text,
.topic-title,
.topic-text,
.about-title,
.about-text,
.footer-copy,
.footer-meta {
  margin: 0;
}

.hero-kicker {
  color: var(--accent);
  font-size: 13px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
}

.hero-title,
.section-title,
.feature-title,
.topic-title,
.about-title {
  color: var(--text-strong);
  font-family: "Noto Serif SC", "Source Han Serif SC", "STSong", serif;
}

.hero-title {
  max-width: 10ch;
  margin-top: 16px;
  font-size: clamp(44px, 7vw, 76px);
  line-height: 0.98;
  letter-spacing: -0.06em;
  font-weight: 700;
}

.hero-summary {
  max-width: 34ch;
  margin-top: 20px;
  color: var(--text-muted);
  font-size: 18px;
  line-height: 1.85;
}

.hero-body {
  max-width: 42ch;
  margin-top: 18px;
  color: var(--text-body);
  font-size: 18px;
  line-height: 1.9;
}

.hero-panel {
  padding: 22px 0 0 24px;
  border-left: 1px solid var(--page-line);
}

.hero-panel-label {
  color: var(--text-muted);
  font-size: 12px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
}

.hero-panel-text {
  margin-top: 14px;
  color: var(--text-body);
  font-size: 17px;
  line-height: 1.9;
}

.hero-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  list-style: none;
  margin: 18px 0 0;
  padding: 0;
}

.hero-tags li {
  padding: 8px 12px;
  color: var(--accent);
  font-size: 13px;
  background: var(--accent-soft);
}

.section-block {
  padding: 34px 0 36px;
  border-bottom: 1px solid var(--page-line);
}

.section-label {
  color: var(--text-muted);
  font-size: 12px;
}

.section-title {
  margin-top: 10px;
  font-size: clamp(28px, 4vw, 42px);
  line-height: 1.08;
  letter-spacing: -0.05em;
}

.section-summary {
  max-width: 48ch;
  margin-top: 10px;
  color: var(--text-muted);
  font-size: 16px;
  line-height: 1.8;
}

.feature-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 26px;
  margin-top: 28px;
}

.feature-item,
.about-item {
  padding-top: 18px;
  border-top: 2px solid var(--page-line-strong);
}

.feature-title,
.about-title {
  font-size: 26px;
  line-height: 1.18;
}

.feature-text,
.about-text {
  margin-top: 12px;
  color: var(--text-muted);
  font-size: 16px;
  line-height: 1.85;
}

.topic-list {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 18px 28px;
  list-style: none;
  margin: 28px 0 0;
  padding: 0;
}

.topic-item {
  padding: 18px 0 0;
  border-top: 1px solid var(--page-line-strong);
}

.topic-meta {
  color: var(--accent);
  font-size: 11px;
}

.topic-title {
  margin-top: 10px;
  font-size: 28px;
  line-height: 1.14;
}

.topic-text {
  margin-top: 10px;
  color: var(--text-muted);
  font-size: 16px;
  line-height: 1.8;
}

.about-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 26px;
  margin-top: 28px;
}

.site-footer {
  display: flex;
  align-items: center;
  justify-content: center;
  flex-direction: column;
  gap: 24px;
  padding-top: 24px;
  text-align: center;
}

.footer-copy {
  max-width: 42ch;
  color: var(--text-muted);
  font-size: 14px;
  line-height: 1.8;
}

.footer-meta {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 18px;
  color: var(--text-strong);
  font-size: 14px;
}

.footer-meta a {
  color: var(--accent);
  border-bottom: 1px solid transparent;
  transition: color 160ms ease, border-color 160ms ease, opacity 160ms ease;
}

.footer-meta a:hover {
  opacity: 0.82;
  border-color: currentColor;
}

@media (max-width: 980px) {
  .hero,
  .feature-grid,
  .about-grid,
  .site-footer {
    grid-template-columns: 1fr;
  }

  .hero {
    gap: 28px;
  }

  .hero-panel {
    padding: 18px 0 0;
    border-left: 0;
    border-top: 1px solid var(--page-line);
  }

  .topic-list {
    grid-template-columns: 1fr;
  }

  .site-footer {
    display: grid;
  }

  .footer-meta {
    justify-content: center;
  }
}

@media (max-width: 720px) {
  .page-shell {
    width: min(calc(100% - 28px), var(--shell-width));
    padding: 18px 0 34px;
  }

  .site-topline {
    align-items: start;
    flex-direction: column;
    gap: 10px;
  }

  .hero {
    padding: 42px 0 56px;
  }

  .hero-title {
    max-width: none;
    font-size: clamp(38px, 14vw, 58px);
  }

  .hero-summary,
  .hero-body,
  .hero-panel-text {
    font-size: 16px;
  }

  .section-title {
    font-size: 30px;
  }

  .feature-title,
  .topic-title,
  .about-title {
    font-size: 22px;
  }
}

@media (prefers-reduced-motion: no-preference) {
  .hero-copy > *,
  .hero-panel,
  .section-block,
  .site-footer {
    animation: rise-in 520ms ease both;
  }

  .hero-copy > .hero-title {
    animation-delay: 70ms;
  }

  .hero-copy > .hero-summary {
    animation-delay: 140ms;
  }

  .hero-copy > .hero-body {
    animation-delay: 210ms;
  }

  .hero-panel {
    animation-delay: 280ms;
  }
}

@keyframes rise-in {
  from {
    opacity: 0;
    transform: translateY(14px);
  }

  to {
    opacity: 1;
    transform: translateY(0);
  }
}