/* ===== 闪连 · 深海光缆(DeepSea Cable)===== */
:root{
  --teal:#0d9488; --teal-deep:#0e7490; --cyan:#22d3ee;
  --abyss:#04222e; --abyss-2:#06303f;
  --bg:#f3fafb; --panel:#ffffff; --line:#d7e9ee; --line-soft:#e8f3f6;
  --ink:#0b2530; --ink-soft:#33505c; --muted:#5b7380;
  --shadow:0 12px 32px rgba(4,34,46,.08);
  --shadow-lg:0 24px 64px rgba(4,34,46,.16);
  --grad:linear-gradient(120deg,#0e7490,#0d9488 55%,#22d3ee);
  --mono:ui-monospace,'SF Mono','Cascadia Code',Consolas,'Courier New',monospace;
}
*{margin:0;padding:0;box-sizing:border-box}
html{scroll-behavior:smooth}
body{font-family:-apple-system,BlinkMacSystemFont,'Segoe UI','PingFang SC','Microsoft YaHei',sans-serif;color:var(--ink);background:var(--bg);line-height:1.7;-webkit-font-smoothing:antialiased}
a{color:inherit;text-decoration:none}
img{max-width:100%;display:block}
.wrap{max-width:1120px;margin:0 auto;padding:0 24px}
h1,h2,h3,h4{line-height:1.25;font-weight:800}

/* ===== 顶部信号条 + 顶栏 ===== */
.signal-strip{height:4px;background:var(--grad)}
.topbar{background:var(--abyss);color:#bdeaf3;font-size:12.5px;text-align:center;padding:7px 16px;letter-spacing:.04em;font-family:var(--mono)}
.topbar .tb-sep{margin:0 8px;color:#3f7a88}

/* ===== 头部 ===== */
.masthead{position:sticky;top:0;z-index:50;background:rgba(255,255,255,.92);backdrop-filter:blur(14px);border-bottom:1px solid var(--line-soft)}
.brand-row{display:flex;align-items:center;justify-content:space-between;padding:14px 0}
.wordmark{display:flex;align-items:center;gap:12px}
.wm-mark{width:36px;height:36px;border-radius:10px}
.wm-text{display:flex;flex-direction:column;line-height:1.1}
.wm-name{font-size:20px;font-weight:800;letter-spacing:.01em;color:var(--ink)}
.wm-sub{font-size:10.5px;font-family:var(--mono);letter-spacing:.14em;color:var(--teal-deep);text-transform:uppercase}
.nav-actions{display:flex;align-items:center;gap:10px}
.nav-search{width:38px;height:38px;border-radius:12px;border:1px solid var(--line);background:var(--panel);font-size:18px;color:var(--teal-deep);cursor:pointer}
.nav-row{display:flex;align-items:center;justify-content:space-between;padding:0 0 12px}
.nav-wrap{display:flex;align-items:center;gap:4px;flex-wrap:wrap}
.nav-wrap>a,.dd>button{padding:8px 15px;border-radius:999px;font-size:14.5px;font-weight:600;color:var(--ink-soft);background:transparent;border:1px solid transparent;cursor:pointer}
.nav-wrap>a:hover,.dd>button:hover{color:var(--teal-deep);background:#e6f4f6;border-color:#cdeaf0}
.nav-wrap>a.on{color:#fff;background:var(--grad)}
.dd{position:relative}
.dd-menu{display:none;position:absolute;top:calc(100% + 8px);left:0;min-width:200px;background:var(--panel);border:1px solid var(--line);border-radius:14px;box-shadow:var(--shadow-lg);padding:8px;z-index:60}
.dd:hover .dd-menu{display:block}
.dd-menu a{display:block;padding:9px 14px;border-radius:9px;font-size:13.5px;color:var(--ink-soft)}
.dd-menu a:hover{background:#e6f4f6;color:var(--teal-deep)}
.nav-toggle{display:none;background:none;border:none;font-size:22px;color:var(--ink);cursor:pointer}

/* ===== 按钮 ===== */
.btn{display:inline-flex;align-items:center;gap:8px;padding:11px 22px;border-radius:999px;font-weight:700;font-size:15px;border:1px solid transparent;cursor:pointer;transition:.18s}
.btn svg{width:17px;height:17px}
.btn-primary{background:var(--grad);color:#fff;box-shadow:0 8px 20px rgba(13,148,136,.28)}
.btn-primary:hover{transform:translateY(-1px);box-shadow:0 12px 26px rgba(13,148,136,.36)}
.btn-ghost{border-color:var(--line);color:var(--teal-deep);background:var(--panel)}
.btn-ghost:hover{border-color:var(--teal);background:#e6f4f6}
.btn-sm{padding:8px 16px;font-size:14px}
.btn-lg{padding:14px 30px;font-size:16px}

/* ===== 区块标题 ===== */
.sec-head{margin-bottom:26px}
.sec-head.left{text-align:left}
.sec-head .kicker{display:inline-block;font-family:var(--mono);font-size:12px;letter-spacing:.16em;text-transform:uppercase;color:var(--teal-deep);margin-bottom:8px}
.sec-head h2{font-size:28px;color:var(--ink)}
.sec-head p{color:var(--muted);margin-top:8px;max-width:680px}

/* ===== hero(分屏 · 海底光缆) ===== */
.hero{position:relative;overflow:hidden;background:
  radial-gradient(820px 460px at 88% -10%,rgba(34,211,238,.14) 0%,transparent 62%),
  radial-gradient(700px 420px at -8% 110%,rgba(13,148,136,.12) 0%,transparent 60%),
  var(--bg)}
.hero .wrap{display:grid;grid-template-columns:1.05fr .95fr;gap:44px;align-items:center;padding-top:64px;padding-bottom:64px;position:relative}
.hero-txt .kicker{display:inline-block;font-family:var(--mono);font-size:12px;letter-spacing:.16em;color:var(--teal-deep);text-transform:uppercase;margin-bottom:16px}
.hero-txt h1{font-size:44px;font-weight:800;letter-spacing:-.01em;margin-bottom:18px;color:var(--ink)}
.hero-txt h1 .hl{background:var(--grad);-webkit-background-clip:text;background-clip:text;color:transparent}
.hero-txt p{font-size:17px;color:var(--muted);max-width:540px;margin-bottom:28px}
.hero-cta{display:flex;gap:14px;flex-wrap:wrap}
.hero-note{font-size:12.5px;color:var(--muted);margin-top:16px;font-family:var(--mono)}
.hero-art{display:flex;justify-content:center;align-items:center}
.hero-art svg{width:100%;max-width:460px;height:auto}
.quick-strip{display:flex;gap:22px;flex-wrap:wrap;margin-top:34px;padding-top:22px;border-top:1px solid var(--line-soft)}
.quick-strip .qs-item{display:flex;flex-direction:column}
.quick-strip .qs-item b{font-size:20px;color:var(--teal-deep)}
.quick-strip .qs-item span{font-size:12.5px;color:var(--muted)}

/* ===== 通用 section ===== */
.section{padding:64px 0}
.section.tint{background:var(--panel);border-top:1px solid var(--line-soft);border-bottom:1px solid var(--line-soft)}

/* ===== 卡片网格 ===== */
.card-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:20px}
.card{background:var(--panel);border:1px solid var(--line);border-radius:18px;padding:26px;box-shadow:var(--shadow);transition:.18s}
.card:hover{transform:translateY(-4px);box-shadow:var(--shadow-lg);border-color:#bfe3ea}
.card .ic{width:46px;height:46px;border-radius:13px;background:#e0f4f6;display:flex;align-items:center;justify-content:center;margin-bottom:16px;color:var(--teal-deep)}
.card .ic svg{width:24px;height:24px}
.card h3{font-size:17px;margin-bottom:8px;color:var(--ink)}
.card p{font-size:14px;color:var(--muted)}
.card h3 .hl{background:var(--grad);-webkit-background-clip:text;background-clip:text;color:transparent}

/* ===== 硬数据区 ===== */
.stat-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:18px}
.stat{background:var(--abyss);border-radius:18px;padding:26px;color:#dff5f9;text-align:center}
.stat b{display:block;font-size:30px;font-weight:800;background:var(--grad);-webkit-background-clip:text;background-clip:text;color:transparent}
.stat span{display:block;font-size:13px;margin-top:6px;color:#7fb2bf}

/* ===== 图文分屏 ===== */
.split{display:grid;grid-template-columns:1fr 1fr;gap:44px;align-items:center;margin:56px 0}
.split.rev{direction:rtl}
.split.rev>*{direction:ltr}
.split img{border-radius:20px;box-shadow:var(--shadow-lg);border:1px solid var(--line)}
.split .s-txt h3{font-size:24px;margin-bottom:14px}
.split .s-txt p{color:var(--muted);margin-bottom:12px}
.split .s-txt ul{list-style:none;margin-top:8px}
.split .s-txt li{padding-left:26px;position:relative;margin-bottom:9px;color:var(--ink-soft)}
.split .s-txt li:before{content:'';position:absolute;left:0;top:9px;width:10px;height:10px;border-radius:50%;background:var(--grad)}

/* ===== 表格 ===== */
.table-wrap{margin:24px 0;overflow-x:auto;border:1px solid var(--line);border-radius:14px;box-shadow:var(--shadow)}
table{width:100%;border-collapse:collapse;font-size:14.5px;background:var(--panel)}
thead th{background:var(--abyss);color:#dff5f9;text-align:left;padding:13px 16px;font-weight:700;white-space:nowrap}
tbody td{padding:12px 16px;border-top:1px solid var(--line-soft);color:var(--ink-soft)}
tbody tr:nth-child(even){background:#f4fafb}

/* ===== 提示/警示/引用 ===== */
.tip,.callout{border-radius:14px;padding:16px 18px;margin:22px 0;font-size:14.5px;line-height:1.7}
.tip{background:#e8f7f6;border:1px solid #bfe9e4;color:#0b5550}
.callout{background:#fff6e8;border:1px solid #f4d9a8;color:#7a5208}
blockquote{border-left:4px solid var(--teal);padding:14px 20px;margin:22px 0;background:#eaf6f7;border-radius:0 14px 14px 0;color:var(--ink-soft);font-style:italic}

/* ===== 场景区 ===== */
.scene-grid{display:grid;grid-template-columns:1fr 1fr;gap:20px}
.scene{background:var(--panel);border:1px solid var(--line);border-radius:18px;padding:28px;box-shadow:var(--shadow)}
.scene .tag{display:inline-block;font-size:11.5px;font-family:var(--mono);letter-spacing:.1em;color:var(--teal-deep);background:#e0f4f6;border-radius:999px;padding:4px 12px;margin-bottom:14px}
.scene h3{font-size:20px;margin-bottom:12px}
.scene p{color:var(--muted);font-size:14.5px}

/* ===== 文章 feed ===== */
.feed-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:20px}
.feed{background:var(--panel);border:1px solid var(--line);border-radius:16px;padding:22px;box-shadow:var(--shadow);display:flex;flex-direction:column;transition:.18s}
.feed:hover{transform:translateY(-4px);box-shadow:var(--shadow-lg)}
.feed .tag{font-size:11.5px;font-family:var(--mono);color:var(--teal-deep);letter-spacing:.08em}
.feed h4{font-size:16px;margin:10px 0 8px;line-height:1.45}
.feed p{font-size:13.5px;color:var(--muted);flex:1}
.feed .more{font-size:13px;color:var(--teal-deep);font-weight:700;margin-top:14px}

/* ===== 口碑 ===== */
.review-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:20px}
.review{background:var(--panel);border:1px solid var(--line);border-radius:16px;padding:24px}
.review p{font-size:14.5px;color:var(--ink-soft);margin-bottom:16px;line-height:1.8}
.review .who{font-size:13px;color:var(--muted);font-family:var(--mono)}

/* ===== FAQ 折叠 ===== */
.faq-list{max-width:820px}
.faq-item{border:1px solid var(--line);border-radius:14px;margin-bottom:12px;background:var(--panel);overflow:hidden}
.faq-q{width:100%;text-align:left;padding:18px 22px;background:none;border:none;font-size:15.5px;font-weight:700;color:var(--ink);cursor:pointer;display:flex;justify-content:space-between;align-items:center}
.faq-q .q-ic{color:var(--teal-deep);font-size:20px;transition:.2s}
.faq-item.open .q-ic{transform:rotate(45deg)}
.faq-a{max-height:0;overflow:hidden;transition:max-height .3s ease}
.faq-item.open .faq-a{max-height:400px}
.faq-a p{padding:0 22px 20px;color:var(--muted);font-size:14.5px}

/* ===== 文章页 ===== */
.article-hero{background:
  radial-gradient(760px 420px at 14% -18%,rgba(34,211,238,.12) 0%,transparent 60%),
  radial-gradient(700px 400px at 92% -10%,rgba(13,148,136,.11) 0%,transparent 60%),
  var(--bg);border-bottom:1px solid var(--line-soft);padding:44px 0 40px;position:relative;overflow:hidden}
.article-hero .wrap.ah-grid{display:grid;grid-template-columns:1fr 360px;gap:40px;align-items:center}
.ah-text{min-width:0}
.ah-fig{margin:0;border-radius:18px;overflow:hidden;border:1px solid var(--line);box-shadow:var(--shadow);aspect-ratio:16/11;background:var(--panel)}
.ah-fig img{width:100%;height:100%;object-fit:cover;display:block}
.article-hero h1{font-size:34px;font-weight:800;letter-spacing:-.01em;margin-bottom:12px;line-height:1.3;color:var(--ink)}
.article-hero p{color:var(--muted);max-width:720px}
.article-meta{display:flex;gap:20px;margin-top:16px;font-size:13px;color:var(--muted);font-family:var(--mono)}
.article-body{padding:44px 0 70px}
.article-body .wrap{display:grid;grid-template-columns:240px 1fr;gap:44px;align-items:start}
.breadcrumb{font-size:13px;color:var(--muted);margin-bottom:16px}
.breadcrumb a{color:var(--teal-deep)}
.breadcrumb .sep{margin:0 8px;color:var(--line)}
.toc{position:sticky;top:90px;align-self:start;background:var(--panel);border:1px solid var(--line);border-radius:16px;padding:18px;box-shadow:var(--shadow)}
.toc h4{font-family:var(--mono);font-size:12px;letter-spacing:.12em;color:var(--teal-deep);text-transform:uppercase;margin-bottom:12px}
.toc a{display:block;font-size:14px;color:var(--muted);padding:6px 0;border-left:2px solid transparent;padding-left:12px}
.toc a:hover{color:var(--teal-deep);border-left-color:var(--teal-deep)}
.prose{font-size:16.5px;line-height:1.9;color:var(--ink-soft)}
.prose h2{font-size:24px;font-weight:800;margin:36px 0 14px;padding-top:14px;color:var(--teal-deep)}
.prose h3{font-size:19px;font-weight:700;margin:24px 0 10px;color:var(--ink)}
.prose .table-wrap{margin:24px 0}
.prose p{margin-bottom:16px}
.prose ul,.prose ol{margin-bottom:16px;padding-left:22px}
.prose li{margin-bottom:8px}
.prose figure{margin:26px 0}
.prose figure img{border-radius:16px;border:1px solid var(--line);box-shadow:var(--shadow)}
.prose figcaption{font-size:13px;color:var(--muted);text-align:center;margin-top:10px}
.prose a{color:var(--teal-deep);border-bottom:1px solid rgba(13,148,136,.3)}
.prose a:hover{color:var(--teal)}

/* ===== 相关卡片 / CTA ===== */
.rel-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:18px;margin-top:22px}
.rel-card{background:var(--panel);border:1px solid var(--line);border-radius:16px;padding:20px;box-shadow:var(--shadow);transition:.18s}
.rel-card:hover{transform:translateY(-3px);box-shadow:var(--shadow-lg)}
.rel-card .tag{font-size:11.5px;font-family:var(--mono);color:var(--teal-deep);letter-spacing:.08em}
.rel-card h4{font-size:15.5px;margin:10px 0 8px;line-height:1.45}
.rel-card p{font-size:13.5px;color:var(--muted)}
.cta-band{background:var(--abyss);border-radius:20px;padding:44px;text-align:center;color:#dff5f9;position:relative;overflow:hidden}
.cta-band h2{font-size:26px;margin-bottom:12px;color:#fff}
.cta-band p{color:#8fc3cf;margin-bottom:24px}
.cta-band .btn-ghost{background:transparent;border-color:#2f6a78;color:#dff5f9}
.cta-band .btn-ghost:hover{border-color:var(--cyan);color:#fff}

/* ===== 教程 hub ===== */
.tut-group{margin:40px 0}
.tut-group .tg-head{display:flex;align-items:center;gap:14px;margin-bottom:18px}
.tut-group .tg-head .tg-num{width:36px;height:36px;border-radius:11px;background:var(--grad);color:#fff;display:flex;align-items:center;justify-content:center;font-weight:800;font-family:var(--mono)}
.tut-group .tg-head h2{font-size:22px}
.tut-group .tg-head span{color:var(--muted);font-size:13px;font-family:var(--mono)}

/* ===== 页脚 ===== */
.mastfoot{background:var(--abyss);color:#a8cfd8;padding:56px 0 24px;margin-top:70px}
.mf-grid{display:grid;grid-template-columns:1.4fr 1fr 1fr 1fr;gap:36px;margin-bottom:40px}
.mf-brand .wordmark{margin-bottom:16px}
.mf-brand .wm-name{color:#fff}
.mf-brand .wm-sub{color:var(--cyan)}
.mf-brand p{font-size:13.5px;line-height:1.8;color:#7fa8b3}
.mf-col h4{font-size:13px;font-family:var(--mono);letter-spacing:.1em;color:#dff5f9;margin-bottom:16px;text-transform:uppercase}
.mf-col a{display:block;font-size:14px;color:#8fc3cf;padding:6px 0}
.mf-col a:hover{color:#fff}
.foot-line{border-top:1px solid rgba(143,195,207,.15);padding-top:20px;text-align:center;font-size:13px;color:#6f97a2}

/* ===== 分享 ===== */
.share{display:flex;gap:10px;flex-wrap:wrap;margin:30px 0;padding-top:20px;border-top:1px dashed var(--line)}
.share a{font-size:13px;padding:7px 14px;border-radius:999px;border:1px solid var(--line);color:var(--teal-deep);background:var(--panel)}
.share a:hover{border-color:var(--teal);background:#e6f4f6}

/* ===== 返回顶部 ===== */
.backtop{position:fixed;right:26px;bottom:26px;width:46px;height:46px;border-radius:14px;background:var(--grad);color:#fff;border:none;font-size:20px;cursor:pointer;box-shadow:var(--shadow-lg);opacity:0;pointer-events:none;transition:.25s;z-index:70}
.backtop.show{opacity:1;pointer-events:auto}

/* ===== 404 / 搜索 ===== */
.util-page{padding:90px 0;text-align:center}
.util-page h1{font-size:54px;background:var(--grad);-webkit-background-clip:text;background-clip:text;color:transparent}
.util-page p{color:var(--muted);margin:18px 0 28px}
.search-box{max-width:520px;margin:0 auto;display:flex;gap:10px}
.search-box input{flex:1;padding:14px 18px;border-radius:999px;border:1px solid var(--line);font-size:15px;background:var(--panel)}
.search-box input:focus{outline:none;border-color:var(--teal)}

/* ===== 响应式 ===== */
@media (max-width:960px){
  .card-grid,.feed-grid,.review-grid,.rel-grid{grid-template-columns:repeat(2,1fr)}
  .stat-grid{grid-template-columns:repeat(2,1fr)}
  .hero .wrap{grid-template-columns:1fr;padding-top:44px;padding-bottom:44px}
  .hero-art{order:-1}
  .hero-art svg{max-width:340px}
  .split{grid-template-columns:1fr;gap:26px}
  .split.rev{direction:ltr}
  .scene-grid{grid-template-columns:1fr}
  .mf-grid{grid-template-columns:1fr 1fr}
  .article-hero .wrap.ah-grid{grid-template-columns:1fr}
  .ah-fig{max-width:440px}
}
@media (max-width:640px){
  .card-grid,.feed-grid,.review-grid,.rel-grid,.stat-grid{grid-template-columns:1fr}
  .nav-row .nav-wrap{display:none}
  .nav-toggle{display:block}
  .hero-txt h1{font-size:32px}
  .article-body .wrap{grid-template-columns:1fr}
  .toc{position:static;display:none}
  .mf-grid{grid-template-columns:1fr}
}