:root {
  --paper: #f7f7f4;
  --white: #ffffff;
  --ink: #17181b;
  --body-ink: #35383d;
  --muted: #686b70;
  --line: #d9dadd;
  --blue: #315eae;
  --display: "Songti SC", "STSong", "SimSun", serif;
  --body: "Microsoft YaHei UI", "PingFang SC", sans-serif;
  --space-1: 4px;
  --space-2: 8px;
  --space-3: 12px;
  --space-4: 16px;
  --space-6: 24px;
  --space-8: 32px;
  --space-12: 48px;
  --space-16: 64px;
  --space-24: 96px;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; background: var(--paper); color: var(--ink); }
body { margin: 0; min-width: 320px; font-family: var(--body); }
::selection { background: var(--blue); color: var(--white); }
a:focus-visible { outline: 2px solid var(--blue); outline-offset: 5px; }

.topbar {
  position: sticky;
  z-index: 10;
  top: 0;
  min-height: 72px;
  padding: 0 clamp(22px, 5vw, 80px);
  display: flex;
  align-items: center;
  justify-content: space-between;
  border-bottom: 1px solid var(--ink);
  background: rgba(247, 247, 244, .96);
  backdrop-filter: blur(12px);
}

.brand { display: inline-flex; align-items: center; gap: 12px; color: var(--ink); text-decoration: none; font-weight: 800; letter-spacing: -.02em; }
.brand-mark { position: relative; width: 25px; height: 25px; rotate: 45deg; border: 7px solid var(--ink); }
.brand-mark i { position: absolute; right: -7px; bottom: -7px; width: 7px; height: 7px; background: var(--blue); }
.section-nav { display: flex; align-items: center; gap: clamp(18px, 3vw, 42px); }
.section-link { padding: 25px 0 22px; border-bottom: 3px solid transparent; color: var(--muted); font-size: 12px; font-weight: 700; text-decoration: none; transition: color .18s ease, border-color .18s ease; }
.section-link:hover { border-color: var(--blue); color: var(--ink); }

main { width: min(1180px, 100%); margin: 0 auto; padding: 0 clamp(22px, 5vw, 72px) var(--space-24); }
.hero { min-height: 480px; display: grid; grid-template-columns: minmax(0, 1fr) minmax(310px, 420px); gap: var(--space-16); align-items: end; padding: var(--space-24) 0 var(--space-16); border-bottom: 1px solid var(--ink); }
h1 { max-width: 820px; margin: 0; font-family: var(--display); font-size: clamp(56px, 7.5vw, 96px); font-weight: 600; line-height: .98; letter-spacing: -.04em; text-wrap: balance; }
.hero-subtitle { max-width: 42ch; margin: var(--space-6) 0 0; color: var(--muted); font-size: 15px; line-height: 1.8; }
.hero-thesis { align-self: end; padding: var(--space-8); background: var(--ink); color: var(--white); }
.hero-thesis span { display: block; margin-bottom: var(--space-4); color: #afc8f4; font-size: 11px; font-weight: 800; letter-spacing: .12em; }
.hero-thesis p { margin: 0; font-family: var(--display); font-size: clamp(22px, 2.1vw, 30px); line-height: 1.55; text-wrap: pretty; }

.executive-summary { display: grid; grid-template-columns: 210px minmax(0, 1fr); gap: var(--space-12); margin-top: var(--space-12); padding: var(--space-12); background: var(--white); border-top: 4px solid var(--blue); }
.executive-summary header span { display: block; margin-bottom: var(--space-2); color: var(--blue); font-size: 11px; font-weight: 800; letter-spacing: .12em; }
.executive-summary h2 { margin: 0; font-family: var(--display); font-size: 36px; font-weight: 600; letter-spacing: -.03em; }
.summary-points { display: grid; }
.summary-point { display: grid; grid-template-columns: 92px minmax(0, 1fr); gap: var(--space-4); align-items: baseline; padding: var(--space-4) 0; border-bottom: 1px solid var(--line); }
.summary-point:first-child { padding-top: 0; }
.summary-point:last-child { padding-bottom: 0; border-bottom: 0; }
.summary-point span { color: var(--blue); font-size: 12px; font-weight: 800; }
.summary-point p { margin: 0; color: var(--ink); font-size: 17px; font-weight: 700; line-height: 1.65; }

.copy-section { scroll-margin-top: 84px; padding-top: var(--space-24); }
.section-heading { display: grid; grid-template-columns: minmax(260px, .9fr) minmax(300px, 1fr); gap: var(--space-12); align-items: end; padding-bottom: var(--space-8); }
.section-heading h2 { max-width: 650px; margin: 0; font-family: var(--display); font-size: clamp(38px, 4.8vw, 62px); font-weight: 600; line-height: 1.12; letter-spacing: -.04em; text-wrap: balance; }
.section-heading > span { max-width: 46ch; color: var(--muted); font-size: 14px; line-height: 1.85; }

.copy-item { display: grid; grid-template-columns: 58px minmax(0, 1fr); gap: var(--space-6); padding: var(--space-12) 0; border-top: 1px solid var(--line); }
.copy-item:first-of-type { border-top-color: var(--ink); }
.copy-item:last-child { border-bottom: 1px solid var(--ink); }
.item-index { padding-top: 7px; color: var(--blue); font-size: 12px; font-weight: 800; font-variant-numeric: tabular-nums; letter-spacing: .12em; }
.item-body { max-width: 860px; }
.question-line { display: flex; align-items: flex-start; gap: var(--space-3); margin-bottom: var(--space-4); }
.question-line > span { flex: none; margin-top: 3px; padding: 4px 7px; background: var(--blue); color: var(--white); font-size: 10px; font-weight: 800; letter-spacing: .08em; }
.item-body h3 { margin: 0; font-size: clamp(18px, 1.7vw, 22px); font-weight: 800; line-height: 1.55; text-wrap: balance; }
.item-body > h3 { margin-bottom: var(--space-4); }
.item-body p { max-width: 70ch; margin: 0; color: var(--body-ink); font-family: var(--display); font-size: clamp(19px, 1.8vw, 23px); line-height: 1.82; text-wrap: pretty; }
.copy-item.priority { margin: var(--space-4) calc(var(--space-6) * -1) 0; padding: var(--space-12) var(--space-6); background: var(--white); border-top-color: var(--blue); }
.copy-item.priority + .copy-item { border-top-color: transparent; }

.copy-item.featured { margin: var(--space-8) 0 0; padding: var(--space-12); border: 0; background: var(--ink); color: var(--white); }
.featured .item-index { color: #afc8f4; }
.featured .question-line > span { background: var(--white); color: var(--ink); }
.featured .item-body h3 { color: #d9dce2; }
.featured .item-body p { max-width: 26ch; color: var(--white); font-size: clamp(29px, 4vw, 48px); line-height: 1.5; letter-spacing: -.025em; }

footer { width: min(1180px, calc(100% - 44px)); margin: 0 auto; padding: var(--space-8) 0 var(--space-12); display: flex; justify-content: space-between; border-top: 1px solid var(--line); color: var(--muted); font-size: 11px; letter-spacing: .08em; text-transform: uppercase; }
footer p { margin: 0; }

@media (max-width: 820px) {
  .topbar { min-height: 62px; }
  .section-nav { gap: 14px; }
  .section-link { padding-block: 21px 18px; font-size: 10px; }
  main { padding-bottom: var(--space-16); }
  .hero { min-height: auto; grid-template-columns: 1fr; gap: var(--space-12); padding: var(--space-16) 0 var(--space-12); }
  .hero-thesis { max-width: 520px; }
  .executive-summary { grid-template-columns: 1fr; gap: var(--space-8); padding: var(--space-8) var(--space-6); }
  .copy-section { padding-top: var(--space-16); }
  .section-heading { grid-template-columns: 1fr; gap: var(--space-4); padding-bottom: var(--space-6); }
  .copy-item { grid-template-columns: 34px minmax(0, 1fr); gap: var(--space-3); padding: var(--space-8) 0; }
  .copy-item.priority { margin-inline: -10px; padding: var(--space-8) 10px; }
  .copy-item.featured { margin-inline: -10px; padding: var(--space-8) 18px var(--space-12); }
  .question-line { display: block; }
  .question-line > span { display: inline-block; margin: 0 0 var(--space-2); }
  footer { width: calc(100% - 44px); }
}

@media (max-width: 520px) {
  .brand > span:last-child { display: none; }
  .summary-point { grid-template-columns: 1fr; gap: var(--space-1); }
  .section-nav { width: calc(100% - 45px); justify-content: space-between; }
  .featured .item-body p { font-size: 28px; }
}

@media print {
  .topbar { position: static; }
  .section-nav { display: none; }
  .hero { min-height: 360px; }
  .copy-section { break-before: page; }
  .copy-item { break-inside: avoid; }
  body { background: #fff; }
}