:root{
  --brand:#1a73e8;
  --brand-2:#6a5cff;
  --brand-3:#00b8d4;
  --accent:#ffd54f;
  --bg:#f6f8fc;
  --bg-soft:#eef2f9;
  --surface:#ffffff;
  --surface-glass:rgba(255,255,255,0.65);
  --border:rgba(26,115,232,0.14);
  --text:#16202e;
  --text-soft:#4a5768;
  --text-mute:#7a8699;
  --shadow-sm:0 2px 8px rgba(22,32,46,0.06);
  --shadow-md:0 10px 30px rgba(22,32,46,0.10);
  --shadow-lg:0 24px 60px rgba(22,32,46,0.16);
  --radius-sm:10px;
  --radius:16px;
  --radius-lg:24px;
  --radius-pill:999px;
  --ease:cubic-bezier(0.22,1,0.36,1);
  --maxw:1180px;
  --grad-banner:linear-gradient(135deg,#1a73e8 0%,#6a5cff 48%,#00b8d4 100%);
}

@media (prefers-color-scheme: dark){
  :root{
    --bg:#0c1220;
    --bg-soft:#111a2c;
    --surface:#131d30;
    --surface-glass:rgba(19,29,48,0.62);
    --border:rgba(120,160,255,0.16);
    --text:#e8eefb;
    --text-soft:#b3c0d6;
    --text-mute:#8b99b2;
    --shadow-sm:0 2px 8px rgba(0,0,0,0.35);
    --shadow-md:0 10px 30px rgba(0,0,0,0.45);
    --shadow-lg:0 24px 60px rgba(0,0,0,0.55);
    --grad-banner:linear-gradient(135deg,#0b3b8c 0%,#3a2fa8 48%,#006b80 100%);
  }
}

*,*::before,*::after{box-sizing:border-box;}

html{
  scroll-behavior:smooth;
  scroll-padding-top:96px;
  -webkit-text-size-adjust:100%;
}

body{
  margin:0;
  font-family:-apple-system,BlinkMacSystemFont,"Segoe UI","PingFang SC","Hiragino Sans GB","Microsoft YaHei","Helvetica Neue",Arial,sans-serif;
  font-size:16px;
  line-height:1.75;
  color:var(--text);
  background:
    radial-gradient(1200px 600px at 85% -10%,rgba(106,92,255,0.12),transparent 60%),
    radial-gradient(900px 500px at -10% 10%,rgba(0,184,212,0.10),transparent 60%),
    var(--bg);
  background-attachment:fixed;
  overflow-x:hidden;
  transition:background-color .4s var(--ease),color .4s var(--ease);
}

img,svg{max-width:100%;height:auto;display:block;}

a{
  color:var(--brand);
  text-decoration:none;
  transition:color .25s var(--ease),opacity .25s var(--ease);
}
a:hover,a:focus-visible{color:var(--brand-2);}
a:focus-visible{outline:2px solid var(--brand-2);outline-offset:3px;border-radius:4px;}

::selection{background:rgba(26,115,232,0.22);color:var(--text);}

/* ============ Header ============ */
header{
  position:sticky;
  top:0;
  z-index:100;
  background:var(--surface-glass);
  -webkit-backdrop-filter:saturate(180%) blur(18px);
  backdrop-filter:saturate(180%) blur(18px);
  border-bottom:1px solid var(--border);
  box-shadow:var(--shadow-sm);
}

header > div{
  max-width:var(--maxw);
  margin:0 auto;
  padding:12px 24px;
  display:flex;
  align-items:center;
  gap:20px;
  flex-wrap:wrap;
}

header > div > a[aria-label="91av官网首页"]{
  font-size:1.5rem;
  font-weight:800;
  letter-spacing:-0.02em;
  background:var(--grad-banner);
  -webkit-background-clip:text;
  background-clip:text;
  -webkit-text-fill-color:transparent;
  color:transparent;
  padding:4px 2px;
  transition:transform .3s var(--ease),filter .3s var(--ease);
}
header > div > a[aria-label="91av官网首页"]:hover{
  transform:scale(1.05);
  filter:brightness(1.15);
}

header nav{flex:1 1 auto;min-width:0;}

header nav ul{
  list-style:none;
  margin:0;
  padding:0;
  display:flex;
  align-items:center;
  gap:4px;
  flex-wrap:wrap;
  justify-content:flex-end;
}

header nav a{
  display:inline-block;
  padding:7px 13px;
  font-size:.9rem;
  font-weight:500;
  color:var(--text-soft);
  border-radius:var(--radius-pill);
  position:relative;
  transition:color .25s var(--ease),background-color .25s var(--ease),transform .25s var(--ease);
}
header nav a:hover,
header nav a:focus-visible{
  color:var(--brand);
  background:rgba(26,115,232,0.09);
  transform:translateY(-1px);
}

/* ============ Main layout ============ */
main{
  max-width:var(--maxw);
  margin:0 auto;
  padding:0 24px 64px;
}

main section{
  margin:56px 0;
  scroll-margin-top:96px;
}

/* ============ Hero ============ */
#hero{
  position:relative;
  margin-top:32px;
  padding:64px 40px;
  border-radius:var(--radius-lg);
  background:var(--grad-banner);
  color:#fff;
  overflow:hidden;
  box-shadow:var(--shadow-lg);
  isolation:isolate;
  animation:fadeUp .8s var(--ease) both;
}

#hero::before{
  content:"";
  position:absolute;
  inset:0;
  background:
    radial-gradient(600px 300px at 90% 0%,rgba(255,255,255,0.28),transparent 65%),
    radial-gradient(500px 260px at 0% 100%,rgba(255,213,79,0.22),transparent 65%);
  z-index:-1;
  pointer-events:none;
}

#hero::after{
  content:"";
  position:absolute;
  width:420px;
  height:420px;
  right:-120px;
  bottom:-160px;
  border-radius:50%;
  background:radial-gradient(circle,rgba(255,255,255,0.22),transparent 70%);
  z-index:-1;
  pointer-events:none;
  animation:float 12s ease-in-out infinite;
}

#hero h1{
  margin:0 0 20px;
  font-size:clamp(1.7rem,3.6vw,2.8rem);
  line-height:1.25;
  font-weight:800;
  letter-spacing:-0.02em;
  color:#fff;
  text-shadow:0 2px 24px rgba(0,0,0,0.18);
}

#hero > p{
  max-width:820px;
  margin:0 0 32px;
  font-size:clamp(.95rem,1.4vw,1.08rem);
  line-height:1.85;
  color:rgba(255,255,255,0.94);
}

#hero figure{
  margin:0;
  border-radius:var(--radius);
  overflow:hidden;
  background:rgba(255,255,255,0.12);
  -webkit-backdrop-filter:blur(10px);
  backdrop-filter:blur(10px);
  border:1px solid rgba(255,255,255,0.28);
  box-shadow:0 18px 50px rgba(0,0,0,0.22);
  transition:transform .5s var(--ease),box-shadow .5s var(--ease);
}
#hero figure:hover{
  transform:translateY(-6px) scale(1.01);
  box-shadow:0 28px 70px rgba(0,0,0,0.3);
}
#hero figure svg{
  width:100%;
  height:auto;
  display:block;
}
#hero figcaption{
  padding:12px 20px;
  font-size:.88rem;
  color:rgba(255,255,255,0.9);
  text-align:center;
  background:rgba(0,0,0,0.16);
  border-top:1px solid rgba(255,255,255,0.18);
}

/* ============ Breadcrumb ============ */
nav[aria-label="面包屑导航"]{
  margin:24px 0 0;
}
nav[aria-label="面包屑导航"] ol{
  list-style:none;
  margin:0;
  padding:0;
  display:flex;
  flex-wrap:wrap;
  gap:8px;
  font-size:.85rem;
  color:var(--text-mute);
}
nav[aria-label="面包屑导航"] li{
  display:flex;
  align-items:center;
  gap:8px;
}
nav[aria-label="面包屑导航"] li + li::before{
  content:"›";
  color:var(--text-mute);
  opacity:.6;
}
nav[aria-label="面包屑导航"] a{
  color:var(--text-soft);
  padding:2px 6px;
  border-radius:6px;
  transition:background-color .25s var(--ease),color .25s var(--ease);
}
nav[aria-label="面包屑导航"] a:hover{
  color:var(--brand);
  background:rgba(26,115,232,0.08);
}
nav[aria-label="面包屑导航"] li[aria-current="page"]{
  color:var(--brand);
  font-weight:600;
}

/* ============ Section headings ============ */
main section > h2{
  position:relative;
  margin:0 0 28px;
  padding-bottom:14px;
  font-size:clamp(1.35rem,2.4vw,1.85rem);
  font-weight:800;
  letter-spacing:-0.015em;
  line-height:1.35;
  color:var(--text);
}
main section > h2::after{
  content:"";
  position:absolute;
  left:0;
  bottom:0;
  width:64px;
  height:4px;
  border-radius:var(--radius-pill);
  background:var(--grad-banner);
  transition:width .5s var(--ease);
}
main section:hover > h2::after{width:110px;}

main section > h3{
  margin:32px 0 12px;
  font-size:clamp(1.05rem,1.7vw,1.25rem);
  font-weight:700;
  line-height:1.5;
  color:var(--text);
  letter-spacing:-0.01em;
}

main section p{
  margin:0 0 16px;
  color:var(--text-soft);
  line-height:1.85;
}

main section ul,
main section ol{
  margin:0 0 20px;
  padding-left:1.4em;
  color:var(--text-soft);
  line-height:1.85;
}
main section li{margin:6px 0;}
main section li::marker{color:var(--brand);}

/* ============ Cards for generic sections ============ */
#about,
#products,
#solutions,
#news,
#articles,
#faq,
#howto,
#knowledge,
#contact,
#sitemap,
#links,
#legal,
#meta-info{
  position:relative;
  padding:36px 36px 28px;
  background:var(--surface);
  border:1px solid var(--border);
  border-radius:var(--radius-lg);
  box-shadow:var(--shadow-sm);
  transition:box-shadow .4s var(--ease),transform .4s var(--ease),border-color .4s var(--ease);
}
#about:hover,
#products:hover,
#solutions:hover,
#news:hover,
#articles:hover,
#faq:hover,
#howto:hover,
#knowledge:hover,
#contact:hover,
#sitemap:hover,
#links:hover,
#legal:hover,
#meta-info:hover{
  box-shadow:var(--shadow-md);
  border-color:rgba(26,115,232,0.28);
}

/* ============ Products advantage list ============ */
#products ul{
  list-style:none;
  padding:0;
  display:grid;
  grid-template-columns:repeat(auto-fit,minmax(240px,1fr));
  gap:14px;
  margin-top:20px;
}
#products ul li{
  position:relative;
  margin:0;
  padding:16px 18px 16px 46px;
  background:var(--bg-soft);
  border:1px solid var(--border);
  border-radius:var(--radius);
  font-size:.95rem;
  color:var(--text-soft);
  transition:transform .3s var(--ease),box-shadow .3s var(--ease),background-color .3s var(--ease);
}
#products ul li::before{
  content:"";
  position:absolute;
  left:16px;
  top:20px;
  width:18px;
  height:18px;
  border-radius:50%;
  background:var(--grad-banner);
  box-shadow:0 0 0 4px rgba(26,115,232,0.12);
}
#products ul li:hover{
  transform:translateY(-4px);
  box-shadow:var(--shadow-md);
  background:var(--surface);
}

/* ============ Solutions list ============ */
#solutions > ul{
  list-style:none;
  padding:0;
  display:grid;
  grid-template-columns:repeat(auto-fit,minmax(220px,1fr));
  gap:14px;
  margin-top:20px;
}
#solutions > ul li{
  margin:0;
  padding:18px 20px;
  background:linear-gradient(160deg,var(--bg-soft),transparent);
  border:1px solid var(--border);
  border-left:4px solid var(--brand);
  border-radius:var(--radius);
  font-size:.95rem;
  transition:transform .3s var(--ease),box-shadow .3s var(--ease),border-left-color .3s var(--ease);
}
#solutions > ul li:hover{
  transform:translateX(4px);
  box-shadow:var(--shadow-md);
  border-left-color:var(--brand-2);
}

/* ============ Cases ============ */
#cases{
  position:relative;
  padding:36px 36px 28px;
  background:var(--surface);
  border:1px solid var(--border);
  border-radius:var(--radius-lg);
  box-shadow:var(--shadow-sm);
  transition:box-shadow .4s var(--ease),border-color .4s var(--ease);
}
#cases:hover{
  box-shadow:var(--shadow-md);
  border-color:rgba(26,115,232,0.28);
}
#cases h3{
  padding-left:16px;
  border-left:4px solid var(--brand);
  border-radius:2px;
}
#cases blockquote{
  margin:18px 0;
  padding:18px 22px;
  background:var(--bg-soft);
  border:1px solid var(--border);
  border-radius:var(--radius);
  position:relative;
  transition:transform .3s var(--ease),box-shadow .3s var(--ease),background-color .3s var(--ease);
}
#cases blockquote::before{
  content:"”";
  position:absolute;
  top:-6px;
  left:14px;
  font-size:2.6rem;
  line-height:1;
  color:var(--brand);
  opacity:.35;
  font-family:Georgia,serif;
}
#cases blockquote p{
  margin:0;
  padding-left:26px;
  font-style:italic;
  color:var(--text-soft);
}
#cases blockquote:hover{
  transform:translateY(-3px);
  box-shadow:var(--shadow-md);
  background:var(--surface);
}

/* ============ News & Articles ============ */
#news article,
#articles article{
  position:relative;
  margin:0 0 18px;
  padding:22px 24px;
  background:var(--bg-soft);
  border:1px solid var(--border);
  border-radius:var(--radius);
  transition:transform .35s var(--ease),box-shadow .35s var(--ease),background-color .35s var(--ease),border-color .35s var(--ease);
}
#news article:last-child,
#articles article:last-child{margin-bottom:0;}

#news article:hover,
#articles article:hover{
  transform:translateY(-5px);
  box-shadow:var(--shadow-md);
  background:var(--surface);
  border-color:rgba(26,115,232,0.3);
}

#news article h3,
#articles article h3{
  margin:0 0 8px;
  font-size:1.08rem;
  line-height:1.5;
  color:var(--text);
  transition:color .25s var(--ease);
}
#news article:hover h3,
#articles article:hover h3{color:var(--brand);}

#news article time,
#articles article time{
  display:inline-block;
  margin-bottom:10px;
  padding:3px 12px;
  font-size:.78rem;
  font-weight:600;
  color:var(--brand);
  background:rgba(26,115,232,0.10);
  border-radius:var(--radius-pill);
  letter-spacing:.02em;
}

#news article p,
#articles article p{
  margin:0 0 8px;
  font-size:.95rem;
}
#articles article p:last-child{margin-bottom:0;}

#articles article a{
  display:inline-flex;
  align-items:center;
  gap:6px;
  font-size:.9rem;
  font-weight:600;
  color:var(--brand);
  padding:6px 0;
  position:relative;
}
#articles article a::after{
  content:"→";
  transition:transform .3s var(--ease);
}
#articles article a:hover::after{transform:translateX(5px);}

/* ============ FAQ ============ */
#faq h3{
  margin:24px 0 8px;
  padding:14px 18px;
  font-size:1rem;
  line-height:1.55;
  color:var(--text);
  background:var(--bg-soft);
  border:1px solid var(--border);
  border-radius:var(--radius-sm);
  cursor:default;
  transition:background-color .3s var(--ease),color .3s var(--ease),border-color .3s var(--ease),transform .3s var(--ease);
}
#faq h3:hover{
  background:rgba(26,115,232,0.08);
  color:var(--brand);
  border-color:rgba(26,115,232,0.3);
  transform:translateX(3px);
}
#faq h3 + p{
  margin:0 0 10px;
  padding:0 18px;
  font-size:.94rem;
  color:var(--text-soft);
}

/* ============ HowTo ============ */
#howto ol{
  counter-reset:step;
  list-style:none;
  padding:0;
  display:grid;
  gap:12px;
  margin-top:18px;
}
#howto ol li{
  counter-increment:step;
  position:relative;
  margin:0;
  padding:16px 20px 16px 60px;
  background:var(--bg-soft);
  border:1px solid var(--border);
  border-radius:var(--radius);
  font-size:.95rem;
  transition:transform .3s var(--ease),box-shadow .3s var(--ease),background-color .3s var(--ease);
}
#howto ol li::before{
  content:counter(step);
  position:absolute;
  left:16px;
  top:50%;
  transform:translateY(-50%);
  width:30px;
  height:30px;
  display:flex;
  align-items:center;
  justify-content:center;
  border-radius:50%;
  background:var(--grad-banner);
  color:#fff;
  font-size:.85rem;
  font-weight:700;
  box-shadow:0 4px 12px rgba(26,115,232,0.3);
}
#howto ol li:hover{
  transform:translateX(4px);
  box-shadow:var(--shadow-md);
  background:var(--surface);
}
#howto ul{
  list-style:none;
  padding:0;
  display:grid;
  gap:10px;
}
#howto ul li{
  position:relative;
  margin:0;
  padding:10px 16px 10px 38px;
  background:var(--bg-soft);
  border-radius:var(--radius-sm);
  font-size:.93rem;
  transition:background-color .3s var(--ease),transform .3s var(--ease);
}
#howto ul li::before{
  content:"✓";
  position:absolute;
  left:14px;
  top:50%;
  transform:translateY(-50%);
  color:var(--brand);
  font-weight:700;
}
#howto ul li:hover{
  background:rgba(26,115,232,0.08);
  transform:translateX(3px);
}

/* ============ Contact ============ */
#contact ul{
  list-style:none;
  padding:0;
  display:grid;
  grid-template-columns:repeat(auto-fit,minmax(260px,1fr));
  gap:12px;
  margin:20px 0;
}
#contact ul li{
  margin:0;
  padding:14px 18px;
  background:var(--bg-soft);
  border:1px solid var(--border);
  border-radius:var(--radius-sm);
  font-size:.93rem;
  color:var(--text-soft);
  transition:transform .3s var(--ease),box-shadow .3s var(--ease),border-color .3s var(--ease);
}
#contact ul li:hover{
  transform:translateY(-3px);
  box-shadow:var(--shadow-md);
  border-color:rgba(26,115,232,0.3);
}
#contact ul li a{
  word-break:break-all;
  font-weight:600;
}

/* ============ Sitemap & Links ============ */
#sitemap ul,
#links ul{
  list-style:none;
  padding:0;
  display:flex;
  flex-wrap:wrap;
  gap:10px;
  margin:0;
}
#sitemap ul li,
#links ul li{margin:0;}
#sitemap ul a,
#links ul a{
  display:inline-block;
  padding:8px 16px;
  font-size:.9rem;
  font-weight:500;
  color:var(--text-soft);
  background:var(--bg-soft);
  border:1px solid var(--border);
  border-radius:var(--radius-pill);
  transition:transform .3s var(--ease),background-color .3s var(--ease),color .3s var(--ease),box-shadow .3s var(--ease),border-color .3s var(--ease);
}
#sitemap ul a:hover,
#links ul a:hover{
  transform:translateY(-3px);
  color:#fff;
  background:var(--grad-banner);
  border-color:transparent;
  box-shadow:0 8px 20px rgba(26,115,232,0.32);
}

/* ============ Legal & Meta ============ */
#legal h3{
  margin-top:20px;
  padding-left:14px;
  border-left:3px solid var(--brand);
}
#meta-info ul{
  list-style:none;
  padding:0;
  display:grid;
  grid-template-columns:repeat(auto-fit,minmax(220px,1fr));
  gap:10px;
}
#meta-info ul li{
  margin:0;
  padding:10px 16px;
  font-size:.88rem;
  color:var(--text-mute);
  background:var(--bg-soft);
  border-radius:var(--radius-sm);
  border:1px dashed var(--border);
}

/* ============ Footer ============ */
footer{
  margin-top:24px;
  padding:40px 24px 48px;
  text-align:center;
  background:linear-gradient(180deg,transparent,var(--bg-soft));
  border-top:1px solid var(--border);
  color:var(--text-mute);
  font-size:.88rem;
  line-height:2;
}
footer p{margin:6px 0;}
footer a{
  color:var(--text-soft);
  font-weight:500;
  padding:2px 4px;
  border-radius:4px;
  transition:color .25s var(--ease),background-color .25s var(--ease);
}
footer a:hover{
  color:var(--brand);
  background:rgba(26,115,232,0.08);
}

/* ============ Animations ============ */
@keyframes fadeUp{
  from{opacity:0;transform:translateY(28px);}
  to{opacity:1;transform:translateY(0);}
}
@keyframes float{
  0%,100%{transform:translate(0,0) scale(1);}
  50%{transform:translate(-24px,-24px) scale(1.08);}
}

@supports (animation-timeline: view()){
  main section{
    animation:fadeUp linear both;
    animation-timeline:view();
    animation-range:entry 0% entry 35%;
  }
}

@media (prefers-reduced-motion: reduce){
  *,*::before,*::after{
    animation-duration:.001ms !important;
    animation-iteration-count:1 !important;
    transition-duration:.001ms !important;
    scroll-behavior:auto !important;
  }
}

/* ============ Responsive ============ */
@media (max-width:1024px){
  header > div{padding:10px 18px;gap:12px;}
  header nav ul{justify-content:flex-start;}
  main{padding:0 18px 48px;}
  #hero{padding:48px 28px;}
  #about,#products,#solutions,#cases,#news,#articles,#faq,#howto,#knowledge,#contact,#sitemap,#links,#legal,#meta-info{
    padding:28px 24px 22px;
  }
}

@media (max-width:768px){
  body{font-size:15px;}
  header > div{
    flex-direction:column;
    align-items:flex-start;
    gap:8px;
    padding:10px 16px;
  }
  header nav{width:100%;}
  header nav ul{
    gap:2px;
    justify-content:flex-start;
    overflow-x:auto;
    flex-wrap:nowrap;
    padding-bottom:4px;
    -webkit-overflow-scrolling:touch;
    scrollbar-width:none;
  }
  header nav ul::-webkit-scrollbar{display:none;}
  header nav a{
    white-space:nowrap;
    font-size:.85rem;
    padding:6px 11px;
  }
  main{padding:0 14px 40px;}
  #hero{
    margin-top:20px;
    padding:36px 20px;
    border-radius:var(--radius);
  }
  #hero h1{margin-bottom:14px;}
  #hero > p{margin-bottom:24px;}
  main section{margin:40px 0;}
  main section > h2{margin-bottom:20px;}
  #about,#products,#solutions,#cases,#news,#articles,#faq,#howto,#knowledge,#contact,#sitemap,#links,#legal,#meta-info{
    padding:22px 18px 16px;
    border-radius:var(--radius);
  }
  #products ul,
  #solutions > ul,
  #contact ul{
    grid-template-columns:1fr;
  }
  #news article,
  #articles article{padding:18px 16px;}
  #howto ol li{padding:14px 16px 14px 54px;}
  #howto ol li::before{left:12px;width:28px;height:28px;}
  footer{padding:32px 16px 40px;}
}

@media (max-width:480px){
  #hero{padding:28px 16px;}
  #hero figcaption{font-size:.8rem;padding:10px 14px;}
  main section > h2::after{width:48px;}
  #sitemap ul a,
  #links ul a{font-size:.84rem;padding:7px 13px;}
  #faq h3{font-size:.94rem;padding:12px 14px;}
  #faq h3 + p{padding:0 14px;font-size:.9rem;}
}

/* ============ Print ============ */
@media print{
  header,nav[aria-label="面包屑导航"],footer,#hero figure{display:none;}
  body{background:#fff;color:#000;}
  main section{box-shadow:none;border:1px solid #ddd;page-break-inside:avoid;}
}