/* =========================================================
   一字成文 YiziPaper · 学术科技蓝（参考产品真实品牌色）
   主色 #002fa7 钴蓝 · 强调 #f3641e 亮橙 · 仅本地字体/资源
   ========================================================= */
:root {
  --blue:       #002fa7;   /* 品牌钴蓝 */
  --blue-d:     #00227a;
  --blue-dd:    #001a5e;
  --blue-tint:  #e8eefc;   /* 浅蓝底 */
  --blue-soft:  #f4f7ff;   /* 极浅蓝分区 */
  --orange:     #f3641e;   /* 强调橙 */
  --orange-d:   #d24e0c;
  --ink:        #1a2030;
  --muted:      #5b6478;
  --faint:      #8b93a6;
  --line:       #e6e9f2;
  --line-2:     #d4d9e8;
  --bg:         #ffffff;
  --radius:     14px;
  --radius-lg:  20px;
  --maxw:       1080px;

  --sans: "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans CJK SC",
          -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }

body {
  margin: 0; color: var(--ink); background: var(--bg);
  font: 16.5px/1.75 var(--sans);
  -webkit-text-size-adjust: 100%;
  -webkit-font-smoothing: antialiased; text-rendering: optimizeLegibility;
}

a { color: var(--blue); text-decoration: none; }
img, svg { max-width: 100%; }

.skip-link {
  position: absolute; left: -999px; top: 8px; z-index: 100;
  background: var(--blue); color: #fff; padding: 8px 14px; border-radius: 8px;
}
.skip-link:focus { left: 12px; }

/* ===================== Header ===================== */
.site-header {
  position: sticky; top: 0; z-index: 20;
  display: flex; align-items: center; justify-content: space-between; gap: 16px;
  padding: 12px clamp(18px, 4vw, 40px);
  background: rgba(255,255,255,.88);
  border-bottom: 1px solid var(--line);
  backdrop-filter: saturate(150%) blur(8px);
}
.brand { display: inline-flex; align-items: center; gap: 10px; color: var(--ink); }
.brand-mark {
  display: grid; place-items: center; width: 34px; height: 34px; border-radius: 9px;
  background: var(--blue); color: #fff; font-family: Georgia, "Songti SC", serif;
  font-size: 19px; font-weight: 700; box-shadow: 0 6px 16px rgba(0,47,167,.3);
}
.brand-text { font-weight: 800; font-size: 18px; letter-spacing: .2px; }
.brand-text em { font-style: normal; color: var(--blue); }

.site-nav ul {
  display: flex; align-items: center; gap: clamp(14px, 2vw, 26px);
  list-style: none; margin: 0; padding: 0;
}
.site-nav a { color: var(--ink); font-size: 15px; font-weight: 500; transition: color .2s; }
.site-nav a:hover { color: var(--blue); }
.nav-cta {
  background: var(--blue); color: #fff !important;
  padding: 8px 18px; border-radius: 999px; font-weight: 700;
  transition: background .2s, transform .2s, box-shadow .2s;
  box-shadow: 0 8px 18px rgba(0,47,167,.28);
}
.nav-cta:hover { background: var(--blue-d); transform: translateY(-1px); }
.nav-toggle {
  display: none; border: 1px solid var(--line-2); background: #fff;
  border-radius: 9px; padding: 8px 14px; font-size: 14px; color: var(--ink); cursor: pointer;
}

/* ===================== Layout ===================== */
main { display: block; }
section { max-width: var(--maxw); margin: 0 auto; padding: clamp(56px, 8vw, 96px) clamp(18px, 4vw, 40px); }
.section-alt { background: var(--blue-soft); max-width: none; border-block: 1px solid var(--line); }
.section-alt > * { max-width: var(--maxw); margin-left: auto; margin-right: auto; }

.section-head { max-width: 760px; margin-bottom: 38px; }
.kicker {
  display: inline-block; font-size: 13px; font-weight: 800; letter-spacing: .14em;
  color: var(--orange); margin-bottom: 12px; text-transform: uppercase;
}
.kicker-light { color: #ffd2b8; }

h1, h2, h3 { font-family: var(--sans); font-weight: 800; line-height: 1.22; letter-spacing: -.01em; }
h1 { font-size: clamp(34px, 6vw, 56px); margin: 0 0 18px; }
h2 { font-size: clamp(25px, 4vw, 38px); margin: 0 0 16px; }
h3 { font-size: 19px; margin: 0 0 10px; }
p { margin: 0 0 12px; }

/* ===================== Hero ===================== */
.hero {
  display: grid; grid-template-columns: 1.05fr .95fr; align-items: center; gap: 40px;
  padding-top: clamp(56px, 8vw, 92px); padding-bottom: clamp(56px, 8vw, 92px);
  overflow-x: clip;
}
.eyebrow {
  display: inline-block; font-size: 13px; font-weight: 800; letter-spacing: .12em;
  color: var(--blue); background: var(--blue-tint); padding: 5px 14px; border-radius: 999px;
  margin: 0 0 18px;
}
.hero h1 .hl { color: var(--orange); }
.lede { max-width: 560px; color: var(--muted); font-size: 18px; }

.hero-actions { display: flex; gap: 14px; flex-wrap: wrap; margin-top: 26px; }

.hero-tags { list-style: none; display: flex; flex-wrap: wrap; gap: 10px; margin: 30px 0 0; padding: 0; }
.hero-tags li {
  font-size: 13.5px; font-weight: 600; color: var(--blue);
  background: #fff; border: 1px solid var(--line-2); border-radius: 999px; padding: 6px 14px;
}

/* 仿产品 UI 预览 */
.hero-preview { perspective: 1200px; }
.app {
  background: #fff; border: 1px solid var(--line-2); border-radius: var(--radius-lg);
  box-shadow: 0 30px 60px -20px rgba(0,47,167,.35); overflow: hidden;
  transform: rotateY(-9deg) rotateX(3deg); transition: transform .5s ease;
}
.hero-preview:hover .app { transform: rotateY(0) rotateX(0); }
.app-bar {
  display: flex; align-items: center; gap: 7px; padding: 11px 16px;
  background: linear-gradient(180deg, #f3f6ff, #e9eefc); border-bottom: 1px solid var(--line);
}
.app-bar .dot { width: 11px; height: 11px; border-radius: 50%; background: #c7cee0; }
.app-bar .dot:first-child { background: var(--orange); }
.app-url { margin-left: 10px; font-size: 12.5px; color: var(--faint); font-weight: 600; }
.app-body { display: grid; grid-template-columns: 116px 1fr; min-height: 260px; }
.app-side { background: var(--blue-soft); border-right: 1px solid var(--line); padding: 14px 10px; display: grid; gap: 8px; }
.side-item {
  font-size: 12.5px; font-weight: 600; color: var(--muted); padding: 8px 10px; border-radius: 9px;
}
.side-item.active { background: var(--blue); color: #fff; box-shadow: 0 6px 14px rgba(0,47,167,.3); }
.app-doc { padding: 18px; position: relative; }
.doc-title { font-size: 14px; font-weight: 800; color: var(--ink); margin-bottom: 14px; }
.line { height: 9px; border-radius: 5px; background: var(--line); margin-bottom: 10px; }
.line.w60 { width: 60%; } .line.w80 { width: 80%; } .line.w90 { width: 90%; }
.line.w95 { width: 95%; } .line.w100 { width: 100%; }
.doc-btn {
  margin-top: 14px; border: 0; cursor: default; background: var(--blue); color: #fff;
  font-weight: 700; font-size: 13px; padding: 9px 18px; border-radius: 9px;
  box-shadow: 0 8px 18px rgba(0,47,167,.3);
}
.doc-chip {
  position: absolute; right: 18px; bottom: 16px; font-size: 11.5px; font-weight: 700;
  color: #fff; background: var(--orange); padding: 5px 10px; border-radius: 999px;
}

/* ===================== Buttons ===================== */
.btn {
  display: inline-block; padding: 12px 24px; border-radius: 999px;
  font-weight: 700; font-size: 15px; transition: transform .2s, background .2s, box-shadow .2s, color .2s, border-color .2s;
}
.btn-primary { background: var(--blue); color: #fff; box-shadow: 0 10px 24px rgba(0,47,167,.3); }
.btn-primary:hover { background: var(--blue-d); transform: translateY(-2px); }
.btn-ghost { border: 1.5px solid var(--line-2); color: var(--ink); }
.btn-ghost:hover { border-color: var(--blue); color: var(--blue); transform: translateY(-2px); }
.btn-orange { background: var(--orange); color: #fff; box-shadow: 0 10px 24px rgba(243,100,30,.35); }
.btn-orange:hover { background: var(--orange-d); transform: translateY(-2px); }
.btn-ghost-light { border: 1.5px solid rgba(255,255,255,.5); color: #fff; }
.btn-ghost-light:hover { border-color: #fff; transform: translateY(-2px); }

/* ===================== Stats ===================== */
.stats {
  display: grid; grid-template-columns: repeat(4, 1fr); gap: 18px;
  max-width: var(--maxw); margin: -28px auto 0; position: relative; z-index: 2;
}
.stat {
  text-align: center; background: #fff; border: 1px solid var(--line);
  border-radius: var(--radius); padding: 22px 14px; box-shadow: 0 14px 30px -16px rgba(0,47,167,.35);
}
.stat b { display: block; font-size: clamp(30px, 5vw, 42px); font-weight: 800; color: var(--blue); line-height: 1; }
.stat span { font-size: 14px; color: var(--muted); margin-top: 8px; display: block; }

/* ===================== Capabilities ===================== */
.card-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(248px, 1fr)); gap: 18px; }
.card {
  position: relative; background: #fff; border: 1px solid var(--line); border-radius: var(--radius);
  padding: 26px 24px 24px; overflow: hidden;
  transition: transform .25s ease, box-shadow .25s ease, border-color .25s ease;
}
.card::before {
  content: ""; position: absolute; left: 0; top: 0; height: 4px; width: 100%;
  background: linear-gradient(90deg, var(--blue), var(--orange));
  transform: scaleX(0); transform-origin: left; transition: transform .4s ease;
}
.card:hover { transform: translateY(-6px); box-shadow: 0 20px 40px -18px rgba(0,47,167,.4); border-color: var(--line-2); }
.card:hover::before { transform: scaleX(1); }
.card .ic {
  display: grid; place-items: center; width: 48px; height: 48px; border-radius: 12px;
  background: var(--blue-tint); font-size: 24px; margin-bottom: 14px;
}
.card h3 { color: var(--ink); }

/* ===================== Flow / Timeline ===================== */
.timeline { list-style: none; margin: 0 auto; max-width: 760px; padding: 0; position: relative; }
#flow .section-head { margin-left: auto; margin-right: auto; }
.timeline::before {
  content: ""; position: absolute; left: 23px; top: 16px; bottom: 16px; width: 2px;
  background: linear-gradient(var(--blue), var(--blue-tint));
}
.timeline li {
  position: relative; padding: 16px 20px 16px 64px; margin-bottom: 14px;
  background: #fff; border: 1px solid var(--line); border-radius: var(--radius);
  transition: transform .2s, box-shadow .2s;
}
.timeline li:hover { transform: translateX(4px); box-shadow: 0 12px 28px rgba(0,47,167,.14); }
.timeline .step {
  position: absolute; left: 11px; top: 50%; transform: translateY(-50%);
  display: grid; place-items: center; width: 26px; height: 26px; border-radius: 50%;
  background: var(--blue); color: #fff; font-weight: 800; font-size: 14px;
}
.timeline strong { display: block; font-size: 17px; color: var(--ink); }
.timeline span { color: var(--muted); }

/* ===================== Scenes ===================== */
.scene-list { list-style: none; margin: 0; padding: 0; columns: 2; column-gap: 30px; }
.scene-list li {
  position: relative; break-inside: avoid; margin-bottom: 14px; padding-left: 26px;
  font-size: 18px; color: var(--ink);
}
.scene-list li::before {
  content: ""; position: absolute; left: 0; top: .62em; width: 9px; height: 9px;
  background: var(--orange); border-radius: 50%;
}

/* ===================== Note ===================== */
.note { position: relative; max-width: 820px; }
.quote-mark {
  position: absolute; left: -4px; top: -8px; font-size: 84px; line-height: 1;
  color: var(--blue); opacity: .16; font-family: Georgia, serif;
}
.note h2 { padding-left: 44px; }
.note p { padding-left: 44px; max-width: 720px; color: var(--muted); font-size: 18px; }

/* ===================== FAQ ===================== */
.faq { display: grid; gap: 12px; max-width: 820px; }
.faq details {
  border: 1px solid var(--line); border-radius: var(--radius); background: #fff;
  padding: 4px 20px; transition: border-color .2s, box-shadow .2s;
}
.faq details[open] { border-color: var(--blue); box-shadow: 0 10px 26px rgba(0,47,167,.12); }
.faq summary {
  cursor: pointer; font-weight: 600; font-size: 17px; padding: 14px 0;
  list-style: none; display: flex; align-items: center; justify-content: space-between; gap: 12px;
}
.faq summary::-webkit-details-marker { display: none; }
.faq summary::after {
  content: "+"; font-size: 24px; color: var(--blue); font-weight: 700; transition: transform .25s;
}
.faq details[open] summary::after { transform: rotate(45deg); }
.faq p { margin: 0 0 16px; color: var(--muted); }

/* ===================== CTA (蓝渐变) ===================== */
.cta {
  position: relative; max-width: none; color: #fff; overflow: hidden;
  background: radial-gradient(120% 140% at 15% 0%, var(--blue) 0%, var(--blue-dd) 70%);
  padding: clamp(60px, 9vw, 104px) clamp(18px, 4vw, 40px);
}
.cta::after {
  content: ""; position: absolute; right: -8%; top: -30%; width: 360px; height: 360px;
  background: radial-gradient(circle, rgba(243,100,30,.4), transparent 70%); pointer-events: none;
}
.cta-inner { position: relative; max-width: 720px; margin: 0 auto; text-align: center; z-index: 1; }
.cta .hero-actions { justify-content: center; }
.cta h2 { color: #fff; }
.cta p { color: rgba(255,255,255,.82); font-size: 19px; }
.cta .contact-note { margin-top: 22px; font-size: 14px; color: rgba(255,255,255,.6); }
.cta .contact-note a { color: #ffd2b8; }

/* ===================== Footer ===================== */
.site-footer { border-top: 1px solid var(--line); background: #fff; }
.footer-inner {
  max-width: var(--maxw); margin: 0 auto; padding: 28px clamp(18px, 4vw, 40px);
  display: flex; align-items: center; gap: 12px; justify-content: center; flex-wrap: wrap;
  color: var(--faint); font-size: 14px; text-align: center;
}
.footer-mark { width: 26px; height: 26px; font-size: 15px; }
.site-footer .footer-inner p { margin: 0; }
.site-footer a { color: var(--blue); font-weight: 700; }

/* ===================== 滚动渐显（无 JS 时默认可见，GEO 友好） ===================== */
.reveal { opacity: 1; transform: none; }
.js .reveal { opacity: 0; transform: translateY(22px); transition: opacity .7s ease, transform .7s cubic-bezier(.2,.7,.2,1); transition-delay: var(--d, 0s); }
.js .reveal.in { opacity: 1; transform: none; }

/* ===================== Responsive ===================== */
@media (max-width: 900px) {
  .hero { grid-template-columns: 1fr; text-align: left; gap: 32px; }
  .hero-preview { max-width: 460px; }
  .app { transform: none; }
  .stats { grid-template-columns: repeat(2, 1fr); margin-top: 8px; }
}
@media (max-width: 720px) {
  .site-nav ul {
    display: none; position: absolute; right: 16px; top: 60px;
    flex-direction: column; align-items: stretch; gap: 6px;
    background: #fff; border: 1px solid var(--line-2); border-radius: var(--radius);
    padding: 14px; box-shadow: 0 16px 40px rgba(0,47,167,.18); min-width: 200px;
  }
  .site-nav ul.open { display: flex; }
  .nav-toggle { display: inline-block; }
  .scene-list { columns: 1; }
  .note h2, .note p { padding-left: 30px; }
  .quote-mark { font-size: 60px; }
  .app-body { grid-template-columns: 96px 1fr; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .js .reveal { opacity: 1 !important; transform: none !important; transition: none; }
  .app { transform: none !important; }
  * { animation: none !important; }
}