:root {
  /* palette */
  --bg:          #FAF8F3;
  --bg-card:     #FFFFFF;
  --bg-soft:     #F3F0E6;
  --ink:         #111111;
  --ink-2:       #46423A;
  --ink-3:       #7A7263;
  --rule:        #E6E0D0;
  --rule-soft:   #EFEBDE;
  --accent:      #FF4D2D;
  --accent-deep: #C93414;
  --accent-soft: #FFE6DE;

  /* geometry */
  --radius-sm:   6px;
  --radius:      12px;
  --shell-max:   1260px;
  --shell-gutter: clamp(20px, 5vw, 56px);

  /* type */
  --font-display: "Instrument Serif", "Noto Serif SC", "Songti SC", Georgia, serif;
  --font-body:    "Inter Tight", -apple-system, BlinkMacSystemFont, "PingFang SC", "Microsoft YaHei", sans-serif;
  --font-mono:    "JetBrains Mono", ui-monospace, "SF Mono", Menlo, monospace;
}

* { box-sizing: border-box; margin: 0; padding: 0; }

html { scroll-behavior: smooth; }

body {
  background: var(--bg);
  color: var(--ink);
  font-family: var(--font-body);
  font-size: 15.5px;
  line-height: 1.6;
  min-height: 100vh;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
  background-image:
    radial-gradient(700px 400px at 15% -5%, rgba(255, 77, 45, 0.05), transparent 60%),
    radial-gradient(900px 500px at 100% 0%, rgba(255, 77, 45, 0.03), transparent 55%);
  background-attachment: fixed;
}

a { color: inherit; text-decoration: none; }
a:hover { color: var(--accent); }
button { font: inherit; color: inherit; cursor: pointer; background: transparent; border: 0; padding: 0; }

/* ============ Shell ============ */
.shell {
  max-width: var(--shell-max);
  margin: 0 auto;
  padding-left: var(--shell-gutter);
  padding-right: var(--shell-gutter);
}

/* ============ Header ============ */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(250, 248, 243, 0.82);
  backdrop-filter: saturate(180%) blur(14px);
  -webkit-backdrop-filter: saturate(180%) blur(14px);
  border-bottom: 1px solid var(--rule);
}
.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 32px;
  height: 68px;
}
.brand {
  display: inline-flex;
  align-items: center;
  gap: 12px;
}
.brand-mark {
  width: 32px; height: 32px;
  display: grid; place-items: center;
  background: var(--ink);
  color: var(--bg);
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 500;
  letter-spacing: 0.05em;
  border-radius: 7px;
}
.brand-mark.small { width: 28px; height: 28px; font-size: 10px; }
.brand-name {
  font-family: var(--font-display);
  font-size: 22px;
  letter-spacing: -0.01em;
  color: var(--ink);
}
.brand-name em {
  font-style: italic;
  color: var(--accent);
  padding-left: 2px;
}
.top-nav {
  display: flex;
  gap: 26px;
  font-size: 13.5px;
  font-weight: 500;
}
.top-nav a {
  color: var(--ink-2);
  position: relative;
  padding: 6px 0;
  transition: color 0.18s ease;
}
.top-nav a::after {
  content: '';
  position: absolute;
  left: 0; right: 0; bottom: 0;
  height: 1.5px;
  background: var(--accent);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 0.28s cubic-bezier(.2,.8,.2,1);
}
.top-nav a:hover { color: var(--ink); }
.top-nav a:hover::after { transform: scaleX(1); }
.clock {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-family: var(--font-mono);
  font-size: 11.5px;
  color: var(--ink-2);
  letter-spacing: 0.03em;
  white-space: nowrap;
}
.clock .dot {
  width: 6px; height: 6px;
  border-radius: 50%;
  background: var(--accent);
  box-shadow: 0 0 0 0 rgba(255, 77, 45, 0.45);
  animation: pulse 2.6s ease-in-out infinite;
}
@keyframes pulse {
  0%, 100% { box-shadow: 0 0 0 0 rgba(255, 77, 45, 0.45); }
  60%      { box-shadow: 0 0 0 6px rgba(255, 77, 45, 0); }
}

/* ============ Hero ============ */
.hero {
  padding: 112px 0 88px;
  position: relative;
}
.hero-grid {
  display: grid;
  grid-template-columns: 1.55fr 1fr;
  gap: 72px;
  align-items: end;
}
.hero-eyebrow {
  font-family: var(--font-mono);
  font-size: 11.5px;
  text-transform: uppercase;
  letter-spacing: 0.14em;
  color: var(--ink-3);
  margin-bottom: 28px;
  display: inline-flex;
  align-items: center;
  gap: 10px;
}
.hero-eyebrow::before {
  content: '';
  width: 24px; height: 1px;
  background: currentColor;
  display: inline-block;
}
.hero-title {
  font-family: var(--font-display);
  font-weight: 400;
  font-size: clamp(44px, 6.6vw, 84px);
  line-height: 1.02;
  letter-spacing: -0.015em;
  color: var(--ink);
  margin-bottom: 32px;
}
.hero-title em {
  /* Chinese: skip synthetic italic (browsers fake-slant CJK awkwardly at large sizes).
     Highlighter-style accent wash under the glyphs reads as editorial emphasis. */
  font-style: normal;
  color: var(--accent);
  display: inline;
  background-image: linear-gradient(to top, var(--accent-soft) 20%, transparent 20%);
  padding: 0 3px;
}
.hero-desc {
  font-size: 17px;
  color: var(--ink-2);
  max-width: 540px;
  line-height: 1.65;
}
.hero-stats {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1px;
  background: var(--rule);
  border: 1px solid var(--rule);
  border-radius: var(--radius);
  overflow: hidden;
}
.stat {
  background: var(--bg-card);
  padding: 22px 24px;
  display: flex;
  flex-direction: column;
  gap: 6px;
  min-height: 110px;
  justify-content: flex-end;
}
.stat-value {
  font-family: var(--font-display);
  font-size: 44px;
  line-height: 1;
  color: var(--ink);
  font-weight: 400;
  letter-spacing: -0.01em;
  font-feature-settings: "tnum" 1;
}
.stat-label {
  font-family: var(--font-mono);
  font-size: 10.5px;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--ink-3);
}

/* ============ Spotlight ============ */
.spotlight {
  padding: 8px 0 64px;
}
.kicker {
  font-family: var(--font-mono);
  font-size: 11.5px;
  text-transform: uppercase;
  letter-spacing: 0.14em;
  color: var(--accent);
  display: inline-flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 18px;
}
.kicker::before {
  content: '';
  width: 26px; height: 1px;
  background: var(--accent);
}
.spotlight-card {
  position: relative;
  padding: 44px 48px;
  background: var(--bg-card);
  border: 1px solid var(--rule);
  border-radius: var(--radius);
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 40px;
  align-items: center;
  transition: border-color 0.25s ease, box-shadow 0.25s ease;
}
.spotlight-card::before {
  content: '';
  position: absolute;
  top: 0; left: 0;
  width: 4px; height: 100%;
  background: var(--accent);
  border-radius: var(--radius) 0 0 var(--radius);
  opacity: 0.9;
}
.spotlight-card:hover {
  border-color: var(--ink);
  box-shadow: 0 12px 40px -24px rgba(17, 17, 17, 0.18);
}
.spotlight-meta {
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--ink-3);
  letter-spacing: 0.05em;
  margin-bottom: 14px;
  text-transform: uppercase;
}
.spotlight-title {
  font-family: var(--font-display);
  font-size: clamp(26px, 3vw, 36px);
  line-height: 1.18;
  font-weight: 400;
  letter-spacing: -0.01em;
  margin-bottom: 6px;
  max-width: 720px;
}
.spotlight-title a { transition: color 0.15s ease; }
.spotlight-title a:hover { color: var(--accent); }
.spotlight-title-en {
  font-family: var(--font-body);
  font-style: italic;
  font-size: 14px;
  color: var(--ink-3);
  display: block;
  margin-bottom: 16px;
}
.spotlight-summary {
  color: var(--ink-2);
  line-height: 1.7;
  max-width: 720px;
  font-size: 15.5px;
}
.spotlight-cta {
  font-family: var(--font-mono);
  font-size: 11.5px;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--ink);
  border: 1px solid var(--ink);
  padding: 13px 22px;
  border-radius: 100px;
  white-space: nowrap;
  transition: all 0.22s ease;
}
.spotlight-cta:hover {
  background: var(--ink);
  color: var(--bg);
}
.spotlight-skel {
  grid-column: 1 / -1;
  height: 180px;
  background: linear-gradient(100deg, var(--bg-card) 30%, var(--bg-soft) 50%, var(--bg-card) 70%);
  background-size: 200% 100%;
  animation: shimmer 1.8s ease-in-out infinite;
  border-radius: var(--radius-sm);
}

/* ============ Section ============ */
.section {
  padding: 72px 0;
  border-top: 1px solid var(--rule);
}
.section-head {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 28px;
  align-items: start;
  margin-bottom: 48px;
}
.section-num {
  font-family: var(--font-display);
  font-style: italic;
  font-size: 60px;
  color: var(--accent);
  line-height: 0.85;
  font-weight: 400;
  padding-top: 8px;
  font-feature-settings: "tnum" 1;
}
.section-title {
  font-family: var(--font-display);
  font-size: 38px;
  font-weight: 400;
  line-height: 1.08;
  letter-spacing: -0.01em;
  margin-bottom: 6px;
}
.section-sub {
  color: var(--ink-3);
  font-size: 14px;
  max-width: 640px;
}
.updated-tag {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 10.5px;
  color: var(--ink-3);
  margin-top: 10px;
  letter-spacing: 0.04em;
}
.section-meta > h2 + p,
.section-meta > h2 + .updated-tag { margin-top: 6px; }

/* ============ Card grid (knowledge / cases / resources) ============ */
.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(290px, 1fr));
  gap: 1px;
  background: var(--rule);
  border: 1px solid var(--rule);
  border-radius: var(--radius);
  overflow: hidden;
}
.card {
  background: var(--bg-card);
  padding: 28px 26px;
  transition: background 0.18s ease;
  display: flex;
  flex-direction: column;
  gap: 10px;
  min-height: 148px;
}
.card:hover { background: #FFFCF4; }
.card-title {
  font-family: var(--font-display);
  font-size: 20px;
  font-weight: 400;
  line-height: 1.22;
  letter-spacing: -0.005em;
  margin-bottom: 0;
}
.card-title a { transition: color 0.15s ease; }
.card-title a:hover { color: var(--accent); }
.card-desc {
  color: var(--ink-2);
  font-size: 14px;
  line-height: 1.6;
}
.card-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  margin-top: 8px;
}
.tag {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 10.5px;
  color: var(--ink-2);
  border: 1px solid var(--rule);
  padding: 3px 8px;
  border-radius: 4px;
  letter-spacing: 0.02em;
  font-weight: 500;
  background: var(--bg);
}
.tag.green {
  color: var(--accent-deep);
  border-color: var(--accent-soft);
  background: var(--accent-soft);
}
.tag.orange {
  color: var(--accent-deep);
  border-color: var(--accent-soft);
}

/* ============ List feed (academic / news) ============ */
.list-feed {
  display: flex;
  flex-direction: column;
}
.feed-row {
  border-top: 1px solid var(--rule);
  padding: 28px 0;
  display: flex;
  flex-direction: column;
  gap: 8px;
  transition: padding-left 0.22s cubic-bezier(.2,.8,.2,1);
}
.feed-row:first-child { border-top: 0; padding-top: 4px; }
.feed-row:hover { padding-left: 6px; }
.feed-row:hover .feed-title { color: var(--accent); }
.feed-title {
  font-family: var(--font-display);
  font-size: 23px;
  font-weight: 400;
  line-height: 1.22;
  letter-spacing: -0.005em;
  color: var(--ink);
  margin-bottom: 0;
  transition: color 0.15s ease;
}
.feed-title a { transition: color 0.15s ease; }
.feed-title-en {
  font-family: var(--font-body);
  font-size: 13.5px;
  font-style: italic;
  color: var(--ink-3);
  margin-top: -2px;
}
.feed-meta {
  font-family: var(--font-mono);
  font-size: 11.5px;
  color: var(--ink-3);
  display: flex;
  gap: 14px;
  flex-wrap: wrap;
  letter-spacing: 0.02em;
  margin-top: 2px;
}
.feed-summary {
  font-size: 15px;
  color: var(--ink-2);
  line-height: 1.72;
  max-width: 720px;
  margin-top: 4px;
}

/* ============ Tabs ============ */
.tab-bar {
  display: flex;
  gap: 0;
  margin-bottom: 24px;
  border-bottom: 1px solid var(--rule);
}
.tab-btn, .res-tab {
  font-size: 13px;
  font-weight: 500;
  color: var(--ink-3);
  padding: 12px 18px 16px;
  position: relative;
  letter-spacing: 0.005em;
  transition: color 0.15s ease;
}
.tab-btn:hover, .res-tab:hover { color: var(--ink); }
.tab-btn.active, .res-tab.active { color: var(--ink); }
.tab-btn.active::after, .res-tab.active::after {
  content: '';
  position: absolute;
  left: 14px; right: 14px; bottom: -1px;
  height: 2px;
  background: var(--accent);
}
.tab-panel { display: none; }
.tab-panel.active { display: block; }

/* ============ Section sub-block (typical cases) ============ */
.section-sub-block {
  margin-top: 72px;
  padding-top: 48px;
  border-top: 1px dashed var(--rule);
}
.sub-title {
  font-family: var(--font-display);
  font-size: 26px;
  font-weight: 400;
  margin-bottom: 24px;
  color: var(--ink);
  display: flex;
  align-items: center;
  gap: 12px;
  letter-spacing: -0.005em;
}
.sub-title::before {
  content: '';
  width: 8px; height: 8px;
  background: var(--accent);
  border-radius: 50%;
}

/* ============ Skeleton loaders ============ */
.skeleton-card, .skeleton-row {
  background: linear-gradient(100deg, var(--bg-card) 30%, var(--bg-soft) 50%, var(--bg-card) 70%);
  background-size: 200% 100%;
  animation: shimmer 1.8s ease-in-out infinite;
}
.skeleton-card { height: 148px; }
.skeleton-row { height: 68px; border-bottom: 1px solid var(--rule); }
@keyframes shimmer {
  0% { background-position: 200% 0; }
  100% { background-position: -200% 0; }
}

/* ============ Footer ============ */
.site-footer {
  border-top: 1px solid var(--rule);
  margin-top: 64px;
  padding: 48px 0;
  color: var(--ink-3);
  font-size: 13px;
}
.footer-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 32px;
  flex-wrap: wrap;
}
.footer-brand {
  display: flex; align-items: center; gap: 14px;
}
.footer-brand strong {
  font-family: var(--font-display);
  font-weight: 400;
  font-size: 16px;
  color: var(--ink);
  letter-spacing: -0.005em;
}
.footer-meta {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.02em;
  color: var(--ink-3);
}

/* ============ Page load staggered reveals ============ */
@keyframes fadeUp {
  from { opacity: 0; transform: translateY(14px); }
  to   { opacity: 1; transform: translateY(0); }
}
.hero-eyebrow { animation: fadeUp 0.55s ease-out 0.05s both; }
.hero-title   { animation: fadeUp 0.7s  ease-out 0.15s both; }
.hero-desc    { animation: fadeUp 0.7s  ease-out 0.3s  both; }
.hero-stats   { animation: fadeUp 0.7s  ease-out 0.45s both; }
.spotlight    { animation: fadeUp 0.7s  ease-out 0.6s  both; }

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}

/* ============ Responsive ============ */
@media (max-width: 960px) {
  .hero { padding: 72px 0 56px; }
  .hero-grid { grid-template-columns: 1fr; gap: 48px; align-items: start; }
  .spotlight-card { grid-template-columns: 1fr; gap: 28px; padding: 32px; }
  .spotlight-cta { justify-self: start; }
  .section { padding: 56px 0; }
  .section-head { gap: 18px; }
  .section-num { font-size: 44px; padding-top: 4px; }
  .section-title { font-size: 28px; }
  .feed-title { font-size: 20px; }
  .card-title { font-size: 18px; }
}
@media (max-width: 720px) {
  .header-inner { height: 60px; }
  .top-nav { display: none; }
  .brand-name { font-size: 19px; }
  .hero-title { font-size: 44px; line-height: 1.05; }
  .stat-value { font-size: 36px; }
}
@media (max-width: 520px) {
  .hero-stats { grid-template-columns: 1fr; }
  .spotlight-card { padding: 24px 22px; }
  .spotlight-card::before { width: 3px; }
  .feed-row { padding: 22px 0; }
  .feed-row:hover { padding-left: 8px; }
}