/* ============================================================
   领航国际官网 | linghang-medtech-ai/static/css/style.css
   国际医疗科技AI大模型 · 全球医疗设备 · 医学影像 · 数字医院
   本样式表为全站唯一样式来源，7个页面共用同一套设计系统。
   ============================================================ */

/* ---------- 1. Design Tokens ---------- */
:root{
  /* 品牌色板：暖白 / 医疗深蓝 / 影像青蓝 / 数字健康青 / 石墨灰 / 安全橙 */
  --c-bg:            #F7F5F0;
  --c-bg-alt:        #EFF3F4;
  --c-surface:       #FFFFFF;
  --c-surface-2:     #F2F6F7;
  --c-line:          #E1E4E4;
  --c-line-soft:     #ECEEEE;

  --c-ink:           #17222D;
  --c-ink-soft:      #46545F;
  --c-ink-faint:     #78848D;

  --c-primary:       #0B3A63;
  --c-primary-700:   #082A49;
  --c-primary-100:   #E5EDF3;

  --c-accent:        #0E8FA6;
  --c-accent-700:    #0B6E80;
  --c-accent-100:    #E1F1F3;

  --c-teal:          #16A38F;
  --c-teal-100:      #E1F4F0;

  --c-gray:          #64707A;
  --c-orange:        #D97B31;
  --c-orange-100:    #FCEEE0;

  --c-red-soft:      #B54A3F;

  --radius-s:  8px;
  --radius-m:  14px;
  --radius-l:  22px;
  --radius-pill: 999px;

  --shadow-s: 0 1px 3px rgba(23,34,45,.06), 0 1px 2px rgba(23,34,45,.04);
  --shadow-m: 0 6px 20px rgba(11,58,99,.08);
  --shadow-l: 0 16px 40px rgba(11,58,99,.12);

  --maxw: 1180px;
  --gap: 24px;

  --font-base: "PingFang SC","Microsoft YaHei","Noto Sans SC",-apple-system,BlinkMacSystemFont,"Segoe UI",sans-serif;
  --font-mono: "SFMono-Regular",Consolas,"Courier New",monospace;
}

/* ---------- 2. Reset ---------- */
*,*::before,*::after{ box-sizing:border-box; }
html{ -webkit-text-size-adjust:100%; scroll-behavior:smooth; }
body{
  margin:0;
  font-family:var(--font-base);
  color:var(--c-ink);
  background:var(--c-bg);
  line-height:1.75;
  font-size:16px;
  overflow-x:hidden;
}
h1,h2,h3,h4,p,ul,ol,figure{ margin:0 0 0 0; }
ul,ol{ padding-left:1.2em; }
img{ max-width:100%; height:auto; display:block; }
a{ color:var(--c-primary); text-decoration:none; }
a:hover{ text-decoration:underline; }
button{ font-family:inherit; }
table{ border-collapse:collapse; width:100%; }

.container{
  max-width:var(--maxw);
  margin:0 auto;
  padding:0 20px;
}

/* ---------- 3. Skip link / a11y ---------- */
.skip-link{
  position:absolute; left:-999px; top:0;
  background:var(--c-primary); color:#fff; padding:10px 16px;
  z-index:999; border-radius:0 0 8px 0;
}
.skip-link:focus{ left:0; }

/* ---------- 4. Topbar / Header ---------- */
.topbar{
  background:var(--c-primary-700);
  color:#cfe0ee;
  font-size:13px;
}
.topbar .container{
  display:flex; justify-content:space-between; align-items:center;
  height:34px;
}
.topbar-tag{ letter-spacing:.02em; }
.topbar a{ color:#cfe0ee; }

.site-header{
  position:sticky; top:0; z-index:100;
  background:rgba(247,245,240,.92);
  backdrop-filter:blur(8px);
  border-bottom:1px solid var(--c-line);
}
.site-header .container{
  display:flex; align-items:center; justify-content:space-between;
  height:72px;
}
.brand{
  display:flex; align-items:center; gap:10px;
  font-weight:700; font-size:19px; color:var(--c-ink);
}
.brand img{ width:36px; height:36px; }
.brand small{
  display:block; font-weight:400; font-size:11px; color:var(--c-ink-faint); letter-spacing:.03em;
}

.nav-toggle{
  display:none;
  width:42px; height:42px;
  border:1px solid var(--c-line);
  border-radius:var(--radius-s);
  background:var(--c-surface);
  cursor:pointer;
  position:relative;
}
.nav-toggle span,
.nav-toggle span::before,
.nav-toggle span::after{
  content:""; position:absolute; left:10px; width:22px; height:2px; background:var(--c-ink);
  transition:transform .2s ease, opacity .2s ease;
}
.nav-toggle span{ top:20px; }
.nav-toggle span::before{ top:-7px; }
.nav-toggle span::after{ top:7px; }
.nav-toggle[aria-expanded="true"] span{ background:transparent; }
.nav-toggle[aria-expanded="true"] span::before{ transform:translateY(7px) rotate(45deg); }
.nav-toggle[aria-expanded="true"] span::after{ transform:translateY(-7px) rotate(-45deg); }

.main-nav ul{
  list-style:none; margin:0; padding:0;
  display:flex; gap:6px;
}
.main-nav a{
  display:block; padding:10px 14px; border-radius:var(--radius-pill);
  color:var(--c-ink-soft); font-size:14.5px; font-weight:600;
  transition:background .15s ease, color .15s ease;
}
.main-nav a:hover,
.main-nav a[aria-current="page"]{
  background:var(--c-primary-100); color:var(--c-primary); text-decoration:none;
}

/* ---------- 5. Hero ---------- */
.hero{
  position:relative;
  padding:64px 0 56px;
  background:
    radial-gradient(1100px 420px at 82% -10%, rgba(14,143,166,.14), transparent 60%),
    linear-gradient(180deg, #FBFAF6 0%, var(--c-bg) 100%);
  border-bottom:1px solid var(--c-line);
}
.hero .container{
  display:grid; grid-template-columns:1.1fr .9fr; gap:48px; align-items:center;
}
.hero-eyebrow{
  display:inline-flex; align-items:center; gap:8px;
  font-size:12.5px; font-weight:700; color:var(--c-accent-700);
  background:var(--c-accent-100); padding:6px 12px; border-radius:var(--radius-pill);
  margin-bottom:18px;
}
.hero h1{
  font-size:clamp(26px,3.6vw,40px);
  line-height:1.35; color:var(--c-ink); font-weight:800;
  letter-spacing:-.01em;
}
.hero .lede{
  margin-top:16px; font-size:16.5px; color:var(--c-ink-soft); max-width:56ch;
}
.hero-actions{ margin-top:26px; display:flex; gap:12px; flex-wrap:wrap; }
.hero-figure{ position:relative; }

.btn{
  display:inline-flex; align-items:center; gap:8px;
  padding:12px 20px; border-radius:var(--radius-pill);
  font-weight:700; font-size:14.5px; border:1px solid transparent; cursor:pointer;
}
.btn-primary{ background:var(--c-primary); color:#fff; }
.btn-primary:hover{ background:var(--c-primary-700); text-decoration:none; }
.btn-outline{ background:var(--c-surface); border-color:var(--c-line); color:var(--c-ink); }
.btn-outline:hover{ border-color:var(--c-primary); color:var(--c-primary); text-decoration:none; }
.btn-sm{ padding:9px 15px; font-size:13.5px; }

/* ---------- 6. Section scaffolding ---------- */
section{ padding:56px 0; }
.section-alt{ background:var(--c-surface-2); }
.section-head{
  max-width:760px; margin:0 0 34px;
}
.section-head.center{ margin-left:auto; margin-right:auto; text-align:center; }
.eyebrow{
  display:inline-block; font-size:12.5px; font-weight:700; letter-spacing:.04em;
  color:var(--c-accent-700); text-transform:uppercase; margin-bottom:10px;
}
h2.section-title{
  font-size:clamp(22px,2.6vw,30px); font-weight:800; color:var(--c-ink); line-height:1.4;
}
.section-desc{ margin-top:12px; color:var(--c-ink-soft); font-size:15.5px; }

h3{ font-size:19px; font-weight:700; color:var(--c-ink); line-height:1.5; }
h4{ font-size:16px; font-weight:700; color:var(--c-ink); }

/* ---------- 7. Chain / flow list ---------- */
.chain{
  display:flex; flex-wrap:wrap; align-items:stretch; gap:10px;
  list-style:none; padding:0; margin:0;
}
.chain li{
  flex:1 1 128px;
  background:var(--c-surface); border:1px solid var(--c-line); border-radius:var(--radius-m);
  padding:14px 12px; text-align:center; font-size:13.5px; font-weight:700; color:var(--c-ink);
  position:relative; display:flex; align-items:center; justify-content:center;
  min-height:64px;
}
.chain li::after{
  content:"→"; position:absolute; right:-15px; top:50%; transform:translateY(-50%);
  color:var(--c-accent); font-weight:900; font-size:15px;
}
.chain li:last-child::after{ display:none; }
@media (max-width:760px){
  .chain{ flex-direction:column; }
  .chain li::after{ content:"↓"; right:auto; left:50%; top:auto; bottom:-15px; transform:translateX(-50%); }
}

/* ---------- 8. Cards ---------- */
.grid{ display:grid; gap:var(--gap); }
.grid-2{ grid-template-columns:repeat(2,1fr); }
.grid-3{ grid-template-columns:repeat(3,1fr); }
.grid-4{ grid-template-columns:repeat(4,1fr); }
@media (max-width:920px){ .grid-3,.grid-4{ grid-template-columns:repeat(2,1fr); } }
@media (max-width:600px){ .grid-2,.grid-3,.grid-4{ grid-template-columns:1fr; } }

.card{
  background:var(--c-surface); border:1px solid var(--c-line); border-radius:var(--radius-l);
  padding:24px; box-shadow:var(--shadow-s);
}
.feature-card{ text-align:left; }
.feature-card img{ width:46px; height:46px; margin-bottom:14px; }
.feature-card h3{ margin-bottom:8px; font-size:16.5px; }
.feature-card p{ color:var(--c-ink-soft); font-size:14.5px; }

/* ---------- 9. Article cards (homepage 8 signature pieces) ---------- */
.article-feature{
  background:var(--c-surface); border:1px solid var(--c-line); border-radius:var(--radius-l);
  padding:0; overflow:hidden; box-shadow:var(--shadow-s); margin-bottom:22px;
}
.article-feature .art-head{
  display:grid; grid-template-columns:210px 1fr; gap:0;
}
.article-feature .art-figure{
  background:var(--c-primary-100); display:flex; align-items:center; justify-content:center; padding:20px;
}
.article-feature .art-figure img{ width:100%; height:auto; }
.article-feature .art-body{ padding:26px 28px; }
.art-meta{
  display:flex; gap:10px; align-items:center; flex-wrap:wrap;
  font-size:12.5px; color:var(--c-ink-faint); margin-bottom:10px;
}
.art-cat{
  background:var(--c-teal-100); color:var(--c-teal); font-weight:700;
  padding:3px 10px; border-radius:var(--radius-pill); font-size:11.5px;
}
.art-index{
  display:inline-flex; align-items:center; justify-content:center;
  width:26px; height:26px; border-radius:50%; background:var(--c-primary); color:#fff;
  font-size:12px; font-weight:800; margin-right:8px;
}
.article-feature h3{ font-size:19.5px; line-height:1.5; margin-bottom:12px; }
.art-abstract{ color:var(--c-ink-soft); font-size:15px; }
.art-preview{ color:var(--c-ink-soft); font-size:15px; margin-top:10px; }
.art-full{
  display:none; color:var(--c-ink-soft); font-size:15px; margin-top:10px;
}
.art-full.is-open{ display:block; }
.art-full h4{ margin-top:20px; margin-bottom:8px; font-size:15.5px; }
.art-full p{ margin-bottom:12px; }
.art-toggle{
  margin-top:16px; background:none; border:1px solid var(--c-line); border-radius:var(--radius-pill);
  padding:9px 16px; font-size:13.5px; font-weight:700; color:var(--c-primary); cursor:pointer;
}
.art-toggle:hover{ border-color:var(--c-primary); background:var(--c-primary-100); }
.art-links{ margin-top:14px; font-size:13.5px; }

@media (max-width:760px){
  .article-feature .art-head{ grid-template-columns:1fr; }
  .article-feature .art-figure{ padding:24px 24px 0; }
}

/* ---------- 10. Observation posts (官网医疗科技观察) ---------- */
.observe-card{
  background:var(--c-surface-2); border:1px solid var(--c-line); border-radius:var(--radius-l);
  padding:26px 28px; margin-bottom:18px;
}
.observe-card h3{ font-size:17.5px; margin-bottom:10px; }
.observe-card p{ color:var(--c-ink-soft); font-size:14.8px; margin-bottom:10px; }

/* ---------- 11. Secondary-page article blocks (full长文) ---------- */
.article-block{
  border-top:1px solid var(--c-line); padding-top:36px; margin-top:36px;
}
.article-block:first-of-type{ border-top:none; padding-top:0; margin-top:0; }
.article-block h2{ font-size:clamp(20px,2.4vw,26px); margin-bottom:10px; }
.article-block .art-meta{ margin-bottom:16px; }
.article-block p{ color:var(--c-ink-soft); font-size:15.3px; margin-bottom:14px; }
.article-block h4{ margin:22px 0 10px; font-size:16px; }
.callout{
  background:var(--c-accent-100); border-left:4px solid var(--c-accent);
  padding:14px 18px; border-radius:var(--radius-s); font-size:14.5px; color:var(--c-ink);
  margin:16px 0;
}
.callout strong{ color:var(--c-accent-700); }

/* ---------- 12. Summary list (二级页面回流首页摘要) ---------- */
.summary-list{ list-style:none; margin:0; padding:0; display:grid; gap:16px; }
.summary-item{
  background:var(--c-surface); border:1px solid var(--c-line); border-radius:var(--radius-m);
  padding:18px 20px;
}
.summary-item h4{ font-size:15.5px; margin-bottom:6px; }
.summary-item a{ color:var(--c-ink); }
.summary-item a:hover{ color:var(--c-primary); }
.summary-item p{ color:var(--c-ink-soft); font-size:14px; margin-top:6px; }
.summary-item .art-meta{ margin-bottom:4px; }

/* ---------- 13. Tables ---------- */
.table-scroll{ overflow-x:auto; border:1px solid var(--c-line); border-radius:var(--radius-m); }
.table-scroll table{ min-width:640px; }
.table-scroll th,.table-scroll td{
  padding:12px 16px; text-align:left; border-bottom:1px solid var(--c-line-soft); font-size:14px;
}
.table-scroll th{ background:var(--c-primary-100); color:var(--c-primary-700); font-weight:700; white-space:nowrap; }
.table-scroll tr:last-child td{ border-bottom:none; }
.table-scroll td{ color:var(--c-ink-soft); }

/* ---------- 14. Tabs (设备分类 / 影像比较) ---------- */
.tabs{ display:flex; gap:8px; flex-wrap:wrap; margin-bottom:18px; }
.tab-btn{
  padding:9px 16px; border-radius:var(--radius-pill); border:1px solid var(--c-line);
  background:var(--c-surface); color:var(--c-ink-soft); font-weight:700; font-size:13.5px; cursor:pointer;
}
.tab-btn[aria-selected="true"]{ background:var(--c-primary); border-color:var(--c-primary); color:#fff; }
.tab-panel{ display:none; }
.tab-panel.is-active{ display:block; }

/* ---------- 15. Timeline (生命周期) ---------- */
.timeline{ list-style:none; margin:0; padding:0; position:relative; }
.timeline::before{
  content:""; position:absolute; left:17px; top:6px; bottom:6px; width:2px; background:var(--c-line);
}
.timeline li{ position:relative; padding:0 0 26px 46px; }
.timeline li:last-child{ padding-bottom:0; }
.timeline li::before{
  content:""; position:absolute; left:9px; top:2px; width:18px; height:18px; border-radius:50%;
  background:var(--c-surface); border:3px solid var(--c-accent);
}
.timeline h4{ margin-bottom:4px; font-size:15.5px; }
.timeline p{ color:var(--c-ink-soft); font-size:14px; margin:0; }

/* ---------- 16. FAQ ---------- */
.faq-item{ border-bottom:1px solid var(--c-line); }
.faq-q{
  width:100%; text-align:left; background:none; border:none; cursor:pointer;
  padding:18px 4px; display:flex; justify-content:space-between; align-items:center; gap:12px;
  font-size:15.5px; font-weight:700; color:var(--c-ink);
}
.faq-q .icon{ flex:none; width:20px; height:20px; position:relative; }
.faq-q .icon::before,.faq-q .icon::after{
  content:""; position:absolute; background:var(--c-primary); border-radius:2px;
}
.faq-q .icon::before{ left:0; top:9px; width:20px; height:2px; }
.faq-q .icon::after{ left:9px; top:0; width:2px; height:20px; transition:transform .2s ease; }
.faq-item[data-open="true"] .icon::after{ transform:scaleY(0); }
.faq-a{ display:none; padding:0 4px 20px; color:var(--c-ink-soft); font-size:14.5px; }
.faq-item[data-open="true"] .faq-a{ display:block; }

/* ---------- 17. Callout / disclaimer boxes ---------- */
.notice{
  border-radius:var(--radius-l); padding:26px 28px; border:1px solid var(--c-line);
}
.notice-edu{ background:linear-gradient(135deg, var(--c-primary-100), var(--c-surface)); }
.notice-warn{ background:var(--c-orange-100); border-color:#F0D3B0; }
.notice h3{ margin-bottom:10px; }
.notice p{ color:var(--c-ink-soft); font-size:14.8px; }
.notice + .notice{ margin-top:16px; }

/* ---------- 18. Badges / pills ---------- */
.pill{
  display:inline-block; padding:4px 12px; border-radius:var(--radius-pill);
  font-size:12px; font-weight:700; background:var(--c-bg-alt); color:var(--c-ink-soft);
  border:1px solid var(--c-line);
}
.pill-blue{ background:var(--c-primary-100); color:var(--c-primary-700); border-color:transparent; }
.pill-teal{ background:var(--c-teal-100); color:var(--c-teal); border-color:transparent; }
.pill-orange{ background:var(--c-orange-100); color:var(--c-orange); border-color:transparent; }

/* ---------- 19. Breadcrumb ---------- */
.breadcrumb{ font-size:13px; color:var(--c-ink-faint); padding:16px 0 0; }
.breadcrumb a{ color:var(--c-ink-faint); }
.breadcrumb a:hover{ color:var(--c-primary); }

/* ---------- 20. App page specifics ---------- */
.app-hero{
  background:linear-gradient(135deg, var(--c-primary) 0%, var(--c-primary-700) 60%, #06213A 100%);
  color:#fff; border-radius:var(--radius-l); padding:40px 32px; position:relative; overflow:hidden;
}
.app-hero .lede{ color:#CBDCEA; }
.app-hero h1{ color:#fff; }
.download-row{ display:flex; gap:14px; flex-wrap:wrap; margin-top:24px; }
.download-btn{
  display:flex; align-items:center; gap:10px; background:rgba(255,255,255,.08);
  border:1px solid rgba(255,255,255,.25); border-radius:var(--radius-m); padding:12px 18px; color:#fff;
}
.download-btn img{ width:26px; height:26px; }
.download-btn .txt{ font-size:12px; opacity:.8; }
.download-btn strong{ display:block; font-size:14.5px; }
.download-note{
  margin-top:18px; font-size:13px; color:#B9CCDD; background:rgba(255,255,255,.06);
  border-radius:var(--radius-s); padding:10px 14px;
}

.app-feature-grid{ display:grid; grid-template-columns:repeat(4,1fr); gap:16px; }
@media (max-width:920px){ .app-feature-grid{ grid-template-columns:repeat(2,1fr); } }
@media (max-width:520px){ .app-feature-grid{ grid-template-columns:1fr; } }
.app-feature{
  background:var(--c-surface); border:1px solid var(--c-line); border-radius:var(--radius-m); padding:18px;
  text-align:center;
}
.app-feature img{ width:40px; height:40px; margin:0 auto 10px; }
.app-feature h4{ font-size:14px; }

/* ---------- 21. Assistant Q&A demo (ai.html) ---------- */
.assistant-demo{
  background:var(--c-ink); color:#EAF0F4; border-radius:var(--radius-l); padding:26px;
}
.assistant-demo .q,.assistant-demo .a{
  border-radius:var(--radius-m); padding:14px 16px; font-size:14.3px; margin-bottom:12px; max-width:88%;
}
.assistant-demo .q{ background:rgba(255,255,255,.08); margin-left:auto; }
.assistant-demo .a{ background:rgba(14,143,166,.18); border:1px solid rgba(14,143,166,.35); }
.assistant-demo .a .tag{ display:block; font-size:11px; color:#7fd9c9; margin-bottom:6px; font-weight:700; }
.assistant-refuse{
  background:rgba(217,123,49,.14); border:1px solid rgba(217,123,49,.35);
}

/* ---------- 22. Footer ---------- */
.site-footer{ background:var(--c-primary-700); color:#C7D6E2; padding:52px 0 26px; margin-top:40px; }
.footer-grid{ display:grid; grid-template-columns:1.4fr 1fr 1fr 1fr; gap:32px; }
@media (max-width:820px){ .footer-grid{ grid-template-columns:1fr 1fr; } }
@media (max-width:520px){ .footer-grid{ grid-template-columns:1fr; } }
.site-footer h4{ color:#fff; font-size:13.5px; margin-bottom:14px; letter-spacing:.03em; }
.site-footer ul{ list-style:none; padding:0; margin:0; }
.site-footer li{ margin-bottom:9px; font-size:13.5px; }
.site-footer a{ color:#C7D6E2; }
.site-footer a:hover{ color:#fff; }
.site-footer p{ font-size:13px; color:#A9BCCB; line-height:1.8; }
.footer-brand{ display:flex; align-items:center; gap:10px; margin-bottom:14px; }
.footer-brand img{ width:30px; height:30px; }
.footer-brand strong{ color:#fff; font-size:16px; }
.footer-bottom{
  border-top:1px solid rgba(255,255,255,.12); margin-top:36px; padding-top:20px;
  display:flex; justify-content:space-between; flex-wrap:wrap; gap:10px; font-size:12.5px; color:#9BB0C0;
}
.footer-disclaimer{
  margin-top:28px; padding-top:22px; border-top:1px solid rgba(255,255,255,.12);
  font-size:12.5px; color:#9BB0C0; line-height:1.9;
}
.footer-disclaimer strong{ color:#C7D6E2; }

/* ---------- 23. Back to top ---------- */
.back-top{
  position:fixed; right:22px; bottom:22px; width:46px; height:46px; border-radius:50%;
  background:var(--c-primary); color:#fff; border:none; cursor:pointer; box-shadow:var(--shadow-m);
  display:flex; align-items:center; justify-content:center; opacity:0; pointer-events:none;
  transition:opacity .2s ease, transform .2s ease; z-index:90;
}
.back-top.is-visible{ opacity:1; pointer-events:auto; }
.back-top:hover{ transform:translateY(-2px); }

/* ---------- 24. Mobile nav ---------- */
@media (max-width:920px){
  .nav-toggle{ display:block; }
  .main-nav{
    position:fixed; inset:72px 0 0 0; background:var(--c-bg); z-index:99;
    transform:translateX(100%); transition:transform .22s ease; overflow-y:auto;
    border-top:1px solid var(--c-line);
  }
  .main-nav.is-open{ transform:translateX(0); }
  .main-nav ul{ flex-direction:column; padding:18px 20px; gap:4px; }
  .main-nav a{ padding:14px 16px; font-size:16px; border-radius:var(--radius-m); }
  .hero .container{ grid-template-columns:1fr; }
  .hero-figure{ order:-1; max-width:320px; margin:0 auto; }
}

@media (max-width:600px){
  .site-header .container{ height:64px; }
  .hero{ padding:40px 0 36px; }
  section{ padding:40px 0; }
  .article-feature .art-body{ padding:20px; }
  .footer-grid{ gap:26px; }
  .app-hero{ padding:28px 20px; }
}

/* ---------- 25. Misc ---------- */
.text-center{ text-align:center; }
.mt-0{ margin-top:0; }
.divider{ height:1px; background:var(--c-line); margin:40px 0; }
.small-note{ font-size:12.5px; color:var(--c-ink-faint); }
.kw-inline{ color:var(--c-accent-700); font-weight:700; }
.hidden{ display:none !important; }

.stat-row{ display:flex; gap:16px; flex-wrap:wrap; margin-top:24px; }
.stat-box{
  flex:1 1 140px; background:var(--c-surface); border:1px solid var(--c-line); border-radius:var(--radius-m);
  padding:16px; text-align:center;
}
.stat-box .num{ font-size:20px; font-weight:800; color:var(--c-primary); }
.stat-box .lbl{ font-size:12px; color:var(--c-ink-faint); margin-top:4px; }