@import url("https://fonts.googleapis.com/css2?family=Archivo:wght@400;500;600;700;800&family=Noto+Serif+SC:wght@400;500;600;700&family=Source+Serif+4:opsz,wght@8..60,400;8..60,500;8..60,600;8..60,700&display=swap");

:root {
  color-scheme: light;
  --paper: #f3eee2;
  --paper-light: #f8f4eb;
  --ink: #1c1a16;
  --accent: #a8432a;
  --muted: #6f675a;
  --rule: #d7cdb9;
  --dark: #17140f;
  --dark-ink: #efe9db;
  --dark-muted: #a99f8c;
  --measure: 820px;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font: 17px/1.82 "Source Serif 4", "Noto Serif SC", Georgia, serif;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}
body::before {
  content: "";
  position: fixed;
  inset: 0 0 auto;
  z-index: 20;
  height: 3px;
  background: var(--accent);
}
.report-progress {
  position: fixed;
  inset: 0 auto auto 0;
  z-index: 100;
  width: 0;
  height: 3px;
  background: var(--accent);
}
.report-masthead {
  position: sticky;
  top: 0;
  z-index: 50;
  display: grid;
  grid-template-columns: minmax(240px, 1fr) auto minmax(160px, 1fr);
  align-items: center;
  gap: 24px;
  min-height: 64px;
  border-bottom: 1px solid rgba(215, 205, 185, .86);
  padding: 12px max(24px, calc((100% - 1300px) / 2));
  background: rgba(243, 238, 226, .94);
  backdrop-filter: blur(12px);
  font-family: "Archivo", sans-serif;
}
.report-masthead a { border: 0; color: #413b31; }
.report-brand {
  color: var(--ink) !important;
  font-family: "Source Serif 4", "Noto Serif SC", serif;
  font-size: 21px;
  font-weight: 700;
  white-space: nowrap;
}
.report-brand span {
  margin-left: 10px;
  color: #8a7f6d;
  font: 600 9px/1 "Archivo", sans-serif;
  letter-spacing: .19em;
  text-transform: uppercase;
}
.report-masthead nav { display: flex; gap: 24px; font-size: 12px; font-weight: 600; }
.report-back { justify-self: end; font-size: 11px; font-weight: 700; letter-spacing: .06em; }
main { width: 100%; margin: 0; padding: 0 0 96px; }
main > header {
  position: relative;
  overflow: hidden;
  border: 0;
  margin: 0 0 72px;
  padding: 76px max(24px, calc((100% - var(--measure)) / 2)) 66px;
  background:
    radial-gradient(circle at 82% 20%, rgba(168,67,42,.28), transparent 52%),
    linear-gradient(rgba(210,190,150,.045) 1px, transparent 1px),
    linear-gradient(90deg, rgba(210,190,150,.045) 1px, transparent 1px),
    var(--dark);
  background-size: auto, 44px 44px, 44px 44px, auto;
  color: var(--dark-ink);
}
main > header::before {
  content: "AI 前沿情报站 · FRONTIER INTELLIGENCE";
  display: block;
  margin-bottom: 42px;
  color: var(--dark-muted);
  font: 600 10px/1 "Archivo", sans-serif;
  letter-spacing: .2em;
}
.eyebrow {
  color: var(--accent);
  font: 700 11px/1 "Archivo", sans-serif;
  letter-spacing: .18em;
  text-transform: uppercase;
}
h1, h2 { font-family: "Source Serif 4", "Noto Serif SC", Georgia, serif; }
h1 {
  max-width: 15ch;
  margin: 20px 0 24px;
  font-size: clamp(44px, 6vw, 66px);
  font-weight: 600;
  line-height: 1.04;
  letter-spacing: -.035em;
  text-wrap: balance;
}
.dek {
  max-width: 62ch;
  margin: 0 0 32px;
  color: #cdc3b0;
  font-size: 20px;
  line-height: 1.72;
}
.meta {
  border-top: 1px solid #37301f;
  padding-top: 22px;
  color: var(--dark-muted);
  font: 500 11px/1 "Archivo", sans-serif;
  letter-spacing: .1em;
}
.report-nav {
  position: sticky;
  top: 64px;
  z-index: 40;
  display: flex;
  justify-content: center;
  gap: clamp(18px, 4vw, 44px);
  overflow-x: auto;
  border-bottom: 1px solid rgba(215, 205, 185, .88);
  padding: 0 24px;
  background: rgba(243, 238, 226, .95);
  backdrop-filter: blur(12px);
  scrollbar-width: none;
}
.report-nav::-webkit-scrollbar { display: none; }
.report-nav a {
  flex: 0 0 auto;
  border: 0;
  padding: 17px 0 15px;
  color: #625a4d;
  font: 600 10px/1 "Archivo", sans-serif;
  letter-spacing: .09em;
  text-transform: uppercase;
}
.report-nav b { margin-right: 5px; color: var(--accent); font-weight: 800; }
.report-nav a:hover { color: var(--ink); }
main > p,
main > h2,
main > footer { width: min(var(--measure), calc(100% - 48px)); margin-right: auto; margin-left: auto; }
main > p { color: #2a251d; }
h2 {
  margin-top: 62px;
  margin-bottom: 22px;
  border-bottom: 1px solid var(--ink);
  padding-bottom: 14px;
  font-size: 31px;
  font-weight: 600;
  line-height: 1.2;
}
.key {
  border: 1px solid var(--rule);
  border-left: 4px solid var(--accent);
  margin-top: 0;
  margin-bottom: 46px;
  padding: 24px 28px;
  background: var(--paper-light);
  font-size: 22px;
  font-weight: 600;
  line-height: 1.6;
}
.report-section {
  width: min(var(--measure), calc(100% - 48px));
  margin: 0 auto;
  padding-top: 88px;
  scroll-margin-top: 118px;
}
.report-section-head {
  display: grid;
  grid-template-columns: auto 1fr;
  align-items: end;
  gap: 24px;
  border-bottom: 1.5px solid var(--ink);
  margin-bottom: 40px;
  padding-bottom: 18px;
}
.report-section-head > span {
  color: var(--accent);
  font: 800 62px/.78 "Archivo", sans-serif;
  letter-spacing: -.04em;
}
.report-section-head small {
  display: block;
  margin-bottom: 10px;
  color: #8a7f6d;
  font: 700 10px/1 "Archivo", sans-serif;
  letter-spacing: .22em;
  text-transform: uppercase;
}
.report-section-head h2 {
  border: 0;
  margin: 0;
  padding: 0;
  font-size: 38px;
  line-height: 1;
}
.report-section h3 {
  margin: 0 0 18px;
  font-family: "Source Serif 4", "Noto Serif SC", Georgia, serif;
  font-size: 27px;
  font-weight: 600;
  line-height: 1.34;
}
.report-section > p:not(.key) { margin: 0 0 22px; color: #2a251d; font-size: 18px; }
.report-section .key { width: auto; }
a { color: var(--accent); text-decoration: none; border-bottom: 1px solid rgba(168,67,42,.35); }
a:hover { color: #8f3620; border-bottom-color: #8f3620; }
footer {
  border-top: 1px solid var(--rule);
  margin-top: 72px;
  padding-top: 24px;
  color: var(--muted);
  font: 600 11px/1.5 "Archivo", sans-serif;
  letter-spacing: .05em;
}
footer a { display: inline-flex; border-bottom: 2px solid var(--accent); padding-bottom: 5px; }

@media (max-width: 620px) {
  body { font-size: 16px; }
  .report-masthead { grid-template-columns: 1fr auto; min-height: 58px; padding: 10px 18px; }
  .report-masthead nav, .report-brand span { display: none; }
  .report-back { font-size: 10px; }
  main > header { margin-bottom: 52px; padding-top: 52px; padding-bottom: 48px; }
  main > header::before { margin-bottom: 32px; font-size: 8px; }
  h1 { font-size: clamp(40px, 13vw, 54px); }
  .dek { font-size: 18px; }
  .report-nav { top: 58px; justify-content: flex-start; padding: 0 18px; }
  .report-section { width: min(100% - 36px, var(--measure)); padding-top: 64px; scroll-margin-top: 108px; }
  .report-section-head { gap: 16px; margin-bottom: 30px; }
  .report-section-head > span { font-size: 47px; }
  .report-section-head h2 { font-size: 31px; }
  .report-section > p:not(.key) { font-size: 16px; }
  .key { padding: 20px; font-size: 19px; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
}