:root {
  --ink: #11110f;
  --paper: #f4f4f0;
  --white: #fff;
  --line: #d8d8d1;
  --muted: #62625c;
  --gold: #f0b90b;
  --gold-dark: #755800;
  --cyan: #0b7683;
  --green: #2f7841;
  --coral: #9b4438;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: "PingFang SC", "Microsoft YaHei", "Noto Sans CJK SC", Arial, sans-serif;
  letter-spacing: 0;
  text-rendering: optimizeLegibility;
}
a { color: inherit; }
img { max-width: 100%; }

.site-header {
  position: sticky;
  top: 0;
  z-index: 20;
  border-bottom: 1px solid rgba(255,255,255,.1);
  background: rgba(11,11,10,.94);
  color: var(--white);
  backdrop-filter: blur(14px);
}
.nav {
  width: min(1120px, calc(100% - 32px));
  height: 64px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
}
.brand {
  display: inline-flex;
  align-items: center;
  gap: 11px;
  color: var(--white);
  font-size: 16px;
  font-weight: 750;
  text-decoration: none;
}
.brand-mark {
  width: 36px;
  height: 36px;
  display: grid;
  place-items: center;
  border-radius: 50%;
  background: var(--gold);
  color: #000;
  font-weight: 900;
}
.nav-links { display: flex; align-items: center; gap: 22px; font-size: 14px; }
.nav-links a { color: rgba(255,255,255,.72); text-decoration: none; }
.nav-links a:hover, .nav-links a[aria-current="page"] { color: var(--white); }
.nav-links .primary { color: #050505; background: var(--gold); padding: 9px 15px; border-radius: 8px; font-weight: 750; }

.hero { background: #0b0b0a; color: var(--white); }
.hero-inner, .section-inner, .article-shell, .footer-inner {
  width: min(1120px, calc(100% - 40px));
  margin: 0 auto;
}
.hero-inner { padding: 78px 0 72px; }
.breadcrumbs { font-size: 14px; color: rgba(255,255,255,.48); }
.breadcrumbs a { text-decoration: none; }
.eyebrow { margin-top: 42px; color: var(--gold); font-size: 15px; font-weight: 800; }
h1 { max-width: 950px; margin: 20px 0 0; font-size: clamp(42px, 6.2vw, 76px); line-height: 1.1; font-weight: 850; }
.hero-lead { max-width: 870px; margin-top: 28px; font-size: clamp(19px, 2.2vw, 25px); line-height: 1.75; color: rgba(255,255,255,.72); }
.hero-lead strong { color: var(--white); }
.meta { margin-top: 30px; font-size: 14px; color: rgba(255,255,255,.46); }

.answer-band { background: var(--gold); }
.answer-band .section-inner { padding: 34px 0; display: grid; grid-template-columns: 180px 1fr; gap: 32px; }
.answer-label { font-size: 16px; font-weight: 850; }
.answer-text { font-size: 21px; line-height: 1.65; font-weight: 650; }

.article-shell { padding: 76px 0 86px; }
.section { padding: 64px 0; border-top: 1px solid var(--line); }
.section:first-child { padding-top: 0; border-top: 0; }
.section h2 { margin: 0; font-size: clamp(32px, 4vw, 46px); line-height: 1.2; }
.section-intro { max-width: 760px; margin-top: 16px; color: var(--muted); font-size: 18px; line-height: 1.75; }
.section h3 { margin: 0; font-size: 23px; line-height: 1.35; }
.section p { font-size: 17px; line-height: 1.8; }

.layer-map { margin-top: 38px; display: grid; grid-template-columns: 1fr 84px 1.08fr; align-items: stretch; }
.tool-list { border-top: 1px solid var(--line); }
.tool-row { display: grid; grid-template-columns: 120px 1fr; gap: 22px; padding: 22px 0; border-bottom: 1px solid var(--line); }
.tool-name { font-size: 20px; font-weight: 800; }
.tool-desc { color: var(--muted); font-size: 16px; line-height: 1.6; }
.layer-arrow { display: grid; place-items: center; color: #8a8a83; font-size: 38px; }
.wudao-layer { padding: 32px; border-radius: 8px; background: var(--ink); color: var(--white); }
.wudao-layer .small { color: var(--gold); font-size: 14px; font-weight: 800; }
.wudao-layer h3 { margin-top: 14px; font-size: 34px; }
.wudao-layer p { margin: 16px 0 0; color: rgba(255,255,255,.68); }
.capability-grid { margin-top: 24px; display: grid; grid-template-columns: repeat(2, 1fr); border: 1px solid #3d3d39; }
.capability-grid span { padding: 13px; border: 1px solid #3d3d39; font-size: 15px; }

.table-scroll { margin-top: 38px; overflow-x: auto; border-top: 1px solid var(--line); }
.comparison { width: 100%; min-width: 900px; border-collapse: collapse; table-layout: fixed; }
.comparison th, .comparison td { padding: 19px 14px; border-bottom: 1px solid var(--line); text-align: left; vertical-align: top; font-size: 15px; line-height: 1.6; }
.comparison th { color: var(--muted); font-weight: 700; }
.comparison th:first-child, .comparison td:first-child { width: 132px; padding-left: 0; }
.comparison .wudao { background: #fff5cf; }
.comparison strong { display: block; margin-bottom: 4px; color: var(--ink); font-size: 18px; }

.media-frame { margin-top: 38px; overflow: hidden; border: 1px solid #2b2b29; border-radius: 8px; background: #0b0b0a; }
.media-frame img { display: block; width: 100%; height: auto; }
.feature-lines { margin-top: 30px; display: grid; grid-template-columns: repeat(2, 1fr); gap: 0 36px; }
.feature-line { padding: 22px 0; border-top: 1px solid var(--line); }
.feature-line h3 { font-size: 21px; }
.feature-line p { margin: 8px 0 0; color: var(--muted); font-size: 16px; }
.feature-line:nth-child(4n+1) h3 { color: var(--gold-dark); }
.feature-line:nth-child(4n+2) h3 { color: var(--cyan); }
.feature-line:nth-child(4n+3) h3 { color: var(--green); }
.feature-line:nth-child(4n+4) h3 { color: var(--coral); }

.steps { margin-top: 38px; border-top: 1px solid var(--line); }
.step { display: grid; grid-template-columns: 90px 280px 1fr; gap: 28px; padding: 27px 0; border-bottom: 1px solid var(--line); }
.step-number { color: var(--gold-dark); font-weight: 850; }
.step p { margin: 0; color: var(--muted); font-size: 16px; }

.prompt { margin-top: 36px; padding: 30px; border-radius: 8px; background: var(--ink); color: var(--white); }
.prompt-label { color: var(--gold); font-size: 14px; font-weight: 850; }
.prompt blockquote { margin: 16px 0 0; font-size: 22px; line-height: 1.7; font-weight: 650; }
.formula { margin-top: 22px; display: grid; grid-template-columns: repeat(4, 1fr); border: 1px solid #393936; }
.formula div { padding: 14px; border: 1px solid #393936; color: rgba(255,255,255,.68); font-size: 14px; line-height: 1.55; }
.formula strong { display: block; color: var(--gold); }

.examples { margin-top: 38px; }
.example { display: grid; grid-template-columns: 165px 1fr; gap: 26px; padding: 22px 0; border-top: 1px solid var(--line); }
.example:last-child { border-bottom: 1px solid var(--line); }
.scene { color: var(--gold-dark); font-weight: 800; }
.example p { margin: 0; color: #30302d; font-size: 17px; font-weight: 520; }

.choice-list, .faq-list, .source-list { margin-top: 34px; border-top: 1px solid var(--line); }
.choice, .faq, .source { padding: 24px 0; border-bottom: 1px solid var(--line); }
.choice { display: grid; grid-template-columns: 220px 1fr; gap: 30px; }
.choice p, .faq p, .source p { margin: 9px 0 0; color: var(--muted); font-size: 16px; }
.faq h3 { font-size: 20px; }
.source a { color: #215d8f; text-underline-offset: 3px; }

.cta-band { background: #0b0b0a; color: var(--white); }
.cta-band .section-inner { padding: 68px 0; }
.cta-band h2 { max-width: 850px; margin: 0; font-size: clamp(36px, 5vw, 56px); line-height: 1.18; }
.cta-band p { max-width: 760px; margin: 20px 0 0; color: rgba(255,255,255,.65); font-size: 19px; line-height: 1.7; }
.actions { margin-top: 30px; display: flex; flex-wrap: wrap; gap: 12px; }
.button { display: inline-flex; align-items: center; min-height: 46px; padding: 11px 18px; border: 1px solid rgba(255,255,255,.22); border-radius: 8px; color: var(--white); font-weight: 750; text-decoration: none; }
.button.primary { border-color: var(--gold); background: var(--gold); color: #050505; }

.guide-index { min-height: calc(100vh - 64px); background: var(--white); }
.guide-index .article-shell { padding-top: 78px; }
.guide-links { margin-top: 44px; border-top: 1px solid var(--line); }
.guide-link { display: grid; grid-template-columns: 190px 1fr auto; gap: 30px; align-items: center; padding: 30px 0; border-bottom: 1px solid var(--line); text-decoration: none; }
.guide-link span { color: var(--gold-dark); font-weight: 800; }
.guide-link p { margin: 8px 0 0; color: var(--muted); }
.guide-link b { font-size: 28px; }

.download-note { margin-top: 24px; color: var(--muted); font-size: 15px; }
.download-note a { color: #215d8f; }

.site-footer { border-top: 1px solid #2f2f2c; background: #0b0b0a; color: rgba(255,255,255,.6); }
.footer-inner { min-height: 96px; display: flex; align-items: center; justify-content: space-between; gap: 24px; font-size: 14px; }
.footer-links { display: flex; flex-wrap: wrap; gap: 20px; }
.footer-links a { text-decoration: none; }

@media (max-width: 760px) {
  .nav { width: min(100% - 24px, 1120px); }
  .nav-links a:not(.primary):not([aria-current="page"]) { display: none; }
  .hero-inner, .section-inner, .article-shell, .footer-inner { width: min(100% - 32px, 1120px); }
  .hero-inner { padding: 52px 0 48px; }
  .eyebrow { margin-top: 28px; }
  h1 { font-size: 42px; }
  .answer-band .section-inner { grid-template-columns: 1fr; gap: 10px; padding: 26px 0; }
  .answer-text { font-size: 18px; }
  .article-shell { padding: 52px 0 64px; }
  .section { padding: 48px 0; }
  .layer-map { grid-template-columns: 1fr; gap: 24px; }
  .layer-arrow { transform: rotate(90deg); }
  .feature-lines { grid-template-columns: 1fr; }
  .step { grid-template-columns: 48px 1fr; gap: 14px; }
  .step p { grid-column: 2; }
  .formula { grid-template-columns: repeat(2, 1fr); }
  .example { grid-template-columns: 1fr; gap: 8px; }
  .choice { grid-template-columns: 1fr; gap: 8px; }
  .guide-link { grid-template-columns: 1fr auto; gap: 12px; }
  .guide-link > div { grid-column: 1 / -1; }
  .footer-inner { padding: 24px 0; align-items: flex-start; flex-direction: column; }
}