:root{
  --ink:#1d2633;
  --ink2:#334255;
  --blue:#416d91;
  --blue-dark:#2f536f;
  --coral:#e04a3f;
  --coral-dark:#b82f27;
  --cream:#f4f0e8;
  --sky:#edf3f7;
  --paper:#fff;
  --line:#d9dfe4;
  --muted:#6b747d;
  --shell:1400px;
}

*{box-sizing:border-box}
html{scroll-behavior:smooth;scroll-padding-top:82px}
body{
  margin:0;min-width:320px;color:var(--ink);background:var(--paper);
  font-family:Arial,"Microsoft YaHei","PingFang SC","Segoe UI",sans-serif;
  line-height:1.75;-webkit-font-smoothing:antialiased;text-rendering:optimizeLegibility
}
img{display:block;max-width:100%}
a{color:inherit;text-decoration:none}
button,a{-webkit-tap-highlight-color:transparent}
button{font:inherit}
.skip-link{position:fixed;top:-90px;left:18px;z-index:1000;padding:10px 15px;color:#fff;background:var(--coral);font-weight:900}
.skip-link:focus{top:18px}
.header-shell,.hero-shell,.hero-question,.section,.final-shell,.footer-shell{width:min(calc(100% - 56px),var(--shell));margin-inline:auto}

.site-header{position:sticky;top:0;z-index:100;background:rgba(255,255,255,.97);border-bottom:1px solid var(--line);backdrop-filter:blur(15px)}
.header-shell{min-height:76px;display:grid;grid-template-columns:255px 1fr 145px;gap:30px;align-items:center}
.brand{width:max-content;display:flex;align-items:center;gap:12px}
.brand-box{padding:6px 12px;background:var(--ink);border-left:4px solid var(--blue)}
.brand-box img{width:auto;height:29px;object-fit:contain}
.brand-caption{color:#8c949c;font-size:8px;font-weight:900;letter-spacing:.13em}
.site-nav{display:flex;justify-content:center;gap:27px;color:#68717a;font-size:12px;font-weight:800}
.site-nav a{padding:24px 0 22px}
.site-nav a:hover,.site-nav a:focus-visible{color:var(--blue-dark)}
.header-cta{justify-self:end;padding:10px 14px;color:#fff;background:var(--coral);font-size:12px;font-weight:900}
.header-cta:hover,.header-cta:focus-visible{background:var(--coral-dark)}
.menu-button{display:none;width:44px;height:44px;background:#fff;border:1px solid var(--line)}
.menu-button span{display:block;width:19px;height:2px;margin:4px auto;background:var(--ink)}

.hero{overflow:hidden;background:linear-gradient(180deg,#fff 0 84%,var(--sky) 84% 100%);border-bottom:1px solid var(--line)}
.hero-shell{min-height:660px;display:grid;grid-template-columns:.88fr 1.12fr;gap:84px;align-items:center;padding:78px 0 58px}
.eyebrow,.section-label{margin:0 0 14px;color:var(--blue-dark);font-size:10px;font-weight:900;letter-spacing:.16em;text-transform:uppercase}
.hero h1{margin:0;max-width:790px;font-size:clamp(56px,6.8vw,96px);line-height:.98;letter-spacing:-.064em}
.hero-lead{max-width:760px;margin:28px 0 0;color:#59636d;font-size:18px;line-height:1.9}
.hero-actions{display:flex;align-items:center;flex-wrap:wrap;gap:24px;margin-top:34px}
.primary-button{min-width:300px;min-height:60px;display:flex;align-items:center;justify-content:space-between;gap:20px;padding:14px 20px;color:#fff;background:var(--coral);font-weight:900}
.primary-button:hover,.primary-button:focus-visible{background:var(--coral-dark)}
.primary-button b{font-size:21px}
.secondary-link{padding-bottom:3px;border-bottom:1px solid currentColor;font-size:13px;font-weight:850}
.hero-devices{display:flex;flex-wrap:wrap;gap:9px;margin-top:34px}
.hero-devices span{padding:7px 11px;color:var(--blue-dark);background:var(--sky);border:1px solid #d5e1e9;font-size:10px;font-weight:900}
.hero-visual{margin:0}
.hero-visual img{width:100%;max-height:480px;object-fit:contain}
.hero-visual figcaption{margin-top:12px;color:var(--muted);font-size:10px;text-align:center}
.hero-question{display:grid;grid-template-columns:120px 380px 1fr;gap:24px;align-items:center;padding:20px 0;border-top:2px solid var(--ink)}
.hero-question span{color:var(--coral);font-size:9px;font-weight:900}
.hero-question strong{font-size:15px}
.hero-question p{margin:0;color:var(--muted);font-size:12px}

.section{padding-top:106px;padding-bottom:106px}
.section-head{display:grid;grid-template-columns:78px 1fr;gap:30px;max-width:1080px}
.section-index{color:var(--blue);font-size:56px;font-weight:950;line-height:1}
.section-head h2,.route-heading h2,.visual-band-copy h2,.install-copy h2,.switch-head h2,.screen-copy h2,.network-layout h2,.help-head h2,.final-copy h2{
  margin:0;font-size:clamp(34px,4.3vw,54px);line-height:1.16;letter-spacing:-.045em
}
.section-head > div > p:not(.section-label),.route-heading > p:not(.section-label),.visual-band-copy > p:not(.section-label),.install-copy > p:not(.section-label),.switch-head > p:not(.section-label),.screen-copy > p:not(.section-label),.network-layout > div:first-child > p:not(.section-label),.help-head > p:not(.section-label){
  margin:20px 0 0;color:var(--muted)
}

.route-section{background:#fff}
.route-heading{max-width:980px}
.route-heading .section-index,.visual-band-copy .section-index,.install-copy .section-index,.switch-head .section-index,.screen-copy .section-index,.network-layout .section-index,.help-head .section-index{display:block;margin-bottom:12px}
.route-map{display:grid;grid-template-columns:repeat(4,1fr);gap:18px;margin-top:50px}
.route-card{min-height:355px;display:grid;grid-template-rows:auto 1fr auto;padding:27px;border-top:5px solid var(--blue);border-bottom:1px solid var(--line);background:var(--sky)}
.route-card:nth-child(2){border-top-color:var(--coral);background:var(--cream)}
.route-card:nth-child(3){border-top-color:#8d6db0;background:#f4f0f6}
.route-card:nth-child(4){border-top-color:var(--ink);background:#f2f3f5}
.route-code{width:48px;height:48px;display:grid;place-items:center;color:#fff;background:var(--ink);border-radius:50%;font-weight:950}
.route-card small{display:block;margin-top:38px;color:var(--blue-dark);font-size:8px;font-weight:900;letter-spacing:.12em}
.route-card h3{margin:5px 0 8px;font-size:20px}
.route-card p{margin:0;color:var(--muted);font-size:12px}
.route-card a{justify-self:start;margin-top:24px;padding-bottom:3px;color:var(--coral);border-bottom:1px solid currentColor;font-size:12px;font-weight:900}

.matrix-section{background:var(--cream)}
.device-table-wrap{margin-top:50px;overflow-x:auto;border-top:2px solid var(--ink)}
.device-table{width:100%;min-width:850px;border-collapse:collapse;background:#fff}
.device-table th,.device-table td{padding:18px 16px;border-bottom:1px solid var(--line);border-right:1px solid var(--line);text-align:left;vertical-align:top}
.device-table thead th{color:#fff;background:var(--ink);font-size:10px;letter-spacing:.08em}
.device-table tbody th{color:var(--blue-dark);font-size:12px}
.device-table tbody td{color:#5f6871;font-size:11px}

.visual-band-section{background:#fff}
.visual-band-copy{max-width:980px}
.wide-visual{margin:48px 0 0}
.wide-visual img{width:100%;max-height:430px;object-fit:cover}
.wide-visual figcaption{margin-top:11px;color:var(--muted);font-size:10px}

.install-section{background:var(--sky)}
.install-layout{display:grid;grid-template-columns:.9fr 1.1fr;gap:78px;align-items:center}
.install-list{margin:32px 0 0;padding:0;list-style:none;border-top:2px solid var(--ink)}
.install-list li{display:grid;grid-template-columns:48px 1fr;gap:18px;padding:17px 0;border-bottom:1px solid #d2dde5}
.install-list li > span{color:var(--coral);font-size:10px;font-weight:900}
.install-list h3{margin:-4px 0 5px;font-size:17px}
.install-list p{margin:0;color:var(--muted);font-size:12px}
.install-visual{margin:0}
.install-visual img{width:100%;max-height:470px;object-fit:contain}
.install-visual figcaption{margin-top:11px;color:var(--muted);font-size:10px;text-align:center}

.switch-section{background:#fff}
.switch-head{max-width:960px}
.switch-story{display:grid;grid-template-columns:1fr 1fr;gap:44px;margin-top:50px}
.switch-story article{min-height:390px;padding:30px 0;border-top:5px solid var(--blue);border-bottom:1px solid var(--line)}
.switch-story article:last-child{border-top-color:var(--coral)}
.switch-story > article > span{color:var(--blue-dark);font-size:9px;font-weight:900;letter-spacing:.12em}
.switch-story h3{margin:60px 0 12px;font-size:28px}
.switch-story p{margin:0;color:var(--muted)}
.switch-story ul{margin:28px 0 0;padding:0;list-style:none;border-top:1px solid var(--line)}
.switch-story li{padding:10px 0;border-bottom:1px solid var(--line);font-size:12px;font-weight:800}

.screen-section{background:var(--ink);color:#fff}
.screen-layout{display:grid;grid-template-columns:1.08fr .92fr;gap:78px;align-items:center}
.screen-visual{margin:0}
.screen-visual img{width:100%;max-height:580px;object-fit:contain}
.screen-copy h2{color:#fff}
.screen-copy > p:not(.section-label){color:#bac2cb}
.screen-copy .section-label{color:#9ec5e0}
.screen-copy .section-index{color:#9ec5e0}
.screen-points{margin-top:30px;border-top:1px solid #465362}
.screen-points article{display:grid;grid-template-columns:70px 1fr;gap:18px;padding:13px 0;border-bottom:1px solid #465362}
.screen-points b{color:#ff9b94;font-size:9px}
.screen-points span{color:#d2d7dd;font-size:12px}

.feature-section{background:#fff}
.feature-pair{display:grid;grid-template-columns:1fr 1fr;gap:28px;margin-top:50px}
.feature-pair figure{margin:0;border:1px solid var(--line);background:#fff}
.feature-pair img{width:100%;aspect-ratio:1.38/1;object-fit:cover}
.feature-pair figcaption{display:grid;padding:20px}
.feature-pair strong{font-size:18px}
.feature-pair span{margin-top:5px;color:var(--muted);font-size:11px}

.network-section{background:var(--cream)}
.network-layout{display:grid;grid-template-columns:.7fr 1.3fr;gap:75px;align-items:start}
.network-grid{display:grid;grid-template-columns:repeat(2,1fr);border-top:1px solid #d5ccbe;border-left:1px solid #d5ccbe}
.network-grid article{min-height:175px;padding:22px;border-right:1px solid #d5ccbe;border-bottom:1px solid #d5ccbe;background:#fff}
.network-grid article:nth-child(2),.network-grid article:nth-child(3),.network-grid article:nth-child(6){background:#f7f3ec}
.network-grid span{color:var(--blue-dark);font-size:9px;font-weight:900}
.network-grid h3{margin:24px 0 7px;font-size:17px}
.network-grid p{margin:0;color:var(--muted);font-size:11px}

.update-section{background:#fff}
.update-timeline{display:grid;grid-template-columns:repeat(4,1fr);margin-top:50px;border-top:2px solid var(--ink);border-left:1px solid var(--line)}
.update-timeline article{min-height:230px;padding:25px;border-right:1px solid var(--line);border-bottom:1px solid var(--line)}
.update-timeline article:nth-child(even){background:var(--sky)}
.update-timeline span{color:var(--coral);font-size:27px;font-weight:950}
.update-timeline strong{display:block;margin-top:42px;font-size:16px}
.update-timeline p{margin:7px 0 0;color:var(--muted);font-size:11px}

.help-section{background:var(--sky)}
.help-head{max-width:980px}
.help-list{display:grid;grid-template-columns:repeat(3,1fr);margin-top:48px;border-top:1px solid #d2dde5;border-left:1px solid #d2dde5}
.help-list article{min-height:190px;padding:23px;background:#fff;border-right:1px solid #d2dde5;border-bottom:1px solid #d2dde5}
.help-list article:nth-child(even){background:#f7fafc}
.help-list span{color:var(--blue-dark);font-size:9px;font-weight:900}
.help-list h3{margin:26px 0 8px;font-size:18px}
.help-list p{margin:0;color:var(--muted);font-size:12px}

.faq-section{background:#fff}
.faq-list{margin-top:50px;border-top:2px solid var(--ink)}
.faq-list details{border-bottom:1px solid var(--line)}
.faq-list summary{position:relative;padding:24px 55px 24px 0;font-size:16px;font-weight:850;cursor:pointer;list-style:none}
.faq-list summary::-webkit-details-marker{display:none}
.faq-list summary span{position:absolute;right:4px;top:20px;width:30px;height:30px;display:grid;place-items:center;color:var(--blue-dark);border:1px solid var(--line);border-radius:50%;transition:transform .2s ease}
.faq-list details[open] summary span{transform:rotate(45deg)}
.faq-list p{margin:-2px 0 23px;color:var(--muted)}

.related-section{background:var(--cream)}
.related-links{display:grid;grid-template-columns:repeat(3,1fr);margin-top:50px;border-top:1px solid #d5ccbe;border-left:1px solid #d5ccbe}
.related-links a{min-height:140px;display:grid;align-content:center;padding:23px;background:#fff;border-right:1px solid #d5ccbe;border-bottom:1px solid #d5ccbe}
.related-links a:hover,.related-links a:focus-visible{background:var(--sky)}
.related-links strong{color:var(--blue-dark);font-size:15px}
.related-links span{margin-top:6px;color:var(--muted);font-size:11px}

.final-section{background:#fff}
.final-shell{min-height:285px;display:grid;grid-template-columns:110px 1fr 245px;gap:42px;align-items:center;padding:44px 0;border-top:5px solid var(--blue);border-bottom:1px solid var(--line)}
.final-index{width:90px;height:110px;display:grid;place-items:center;align-content:center;color:#fff;background:var(--ink)}
.final-index span{font-size:40px;font-weight:950;line-height:1}
.final-index small{margin-top:5px;color:#9ec5e0;font-size:8px;font-weight:900}
.final-copy p{margin:0 0 9px;color:var(--blue-dark);font-size:9px;font-weight:900;letter-spacing:.13em}
.final-copy h2{font-size:clamp(29px,3.6vw,44px)}
.final-copy span{display:block;margin-top:13px;color:var(--muted);font-size:11px}
.final-button{min-height:70px;display:flex;align-items:center;justify-content:space-between;gap:18px;padding:16px 20px;color:#fff;background:var(--coral);font-weight:900}
.final-button:hover,.final-button:focus-visible{background:var(--coral-dark)}
.final-button b{font-size:20px}

.site-footer{padding:52px 0 32px;color:#b7c0c9;background:var(--ink)}
.footer-shell{display:grid;grid-template-columns:1fr auto;gap:32px 55px}
.footer-brand img{width:auto;height:34px;object-fit:contain}
.footer-brand p{max-width:820px;margin:17px 0 0;color:#75818d;font-size:11px}
.footer-nav{display:grid;grid-template-columns:repeat(2,auto);gap:8px 25px;font-size:12px;font-weight:700}
.footer-nav a:hover,.footer-nav a:focus-visible{color:#fff}
.copyright{grid-column:1/-1;margin:5px 0 0;padding-top:21px;color:#535f6b;border-top:1px solid #3c4856;font-size:11px}
.mobile-sticky{display:none}

@media(max-width:1100px){
  .header-shell{grid-template-columns:230px 1fr 135px}
  .site-nav{gap:16px}
  .route-map{grid-template-columns:repeat(2,1fr)}
  .update-timeline{grid-template-columns:repeat(2,1fr)}
}
@media(max-width:820px){
  html{scroll-padding-top:72px}
  .header-shell{min-height:70px;grid-template-columns:1fr auto}
  .header-cta{display:none}
  .menu-button{display:block}
  .site-nav{position:absolute;left:20px;right:20px;top:calc(100% + 8px);display:none;padding:10px;background:#fff;border:1px solid var(--line);box-shadow:0 22px 55px rgba(0,0,0,.18)}
  .site-nav.is-open{display:grid}
  .site-nav a{padding:10px 12px}
  .hero{background:#fff}
  .hero-shell{grid-template-columns:1fr}
  .hero-copy{text-align:center}
  .hero-actions,.hero-devices{justify-content:center}
  .hero-visual{width:min(100%,800px);margin-inline:auto}
  .hero-question{grid-template-columns:105px 1fr}
  .hero-question p{grid-column:2}
  .install-layout,.screen-layout,.network-layout{grid-template-columns:1fr}
  .switch-story{grid-template-columns:1fr}
  .help-list{grid-template-columns:repeat(2,1fr)}
  .final-shell{grid-template-columns:100px 1fr}
  .final-button{grid-column:2;width:245px}
  .footer-shell{grid-template-columns:1fr}
  .copyright{grid-column:auto}
}
@media(max-width:600px){
  body{padding-bottom:70px}
  .header-shell,.hero-shell,.hero-question,.section,.final-shell,.footer-shell{width:min(calc(100% - 28px),var(--shell))}
  .brand-caption{display:none}
  .brand-box img{height:27px}
  .hero-shell{min-height:0;padding:55px 0 48px}
  .hero h1{font-size:clamp(45px,13.5vw,64px)}
  .hero-lead{font-size:16px}
  .hero-actions{display:grid}
  .primary-button{min-width:0;width:100%}
  .secondary-link{justify-self:center}
  .hero-question{grid-template-columns:1fr;gap:6px;text-align:center;padding:17px 0}
  .hero-question p{grid-column:auto}
  .section{padding-top:72px;padding-bottom:72px}
  .section-head{grid-template-columns:1fr;gap:10px}
  .section-index{font-size:42px}
  .section-head h2,.route-heading h2,.visual-band-copy h2,.install-copy h2,.switch-head h2,.screen-copy h2,.network-layout h2,.help-head h2{font-size:clamp(30px,10vw,41px)}
  .route-map,.feature-pair,.network-grid,.update-timeline,.help-list,.related-links{grid-template-columns:1fr}
  .route-card{min-height:0}
  .switch-story article{min-height:0}
  .switch-story h3{margin-top:38px}
  .wide-visual img{object-fit:contain}
  .screen-visual img{max-height:430px}
  .network-grid article,.update-timeline article,.help-list article{min-height:0}
  .faq-list summary{font-size:15px}
  .final-shell{grid-template-columns:1fr;padding:34px 0}
  .final-index{width:76px;height:90px}
  .final-button{grid-column:auto;width:100%}
  .footer-nav{grid-template-columns:1fr 1fr}
  .mobile-sticky{
    position:fixed;left:0;right:0;bottom:0;z-index:120;min-height:70px;
    display:flex;justify-content:space-between;align-items:center;gap:12px;
    padding:9px 14px;color:#fff;background:rgba(29,38,51,.97);border-top:1px solid #455263
  }
  .mobile-sticky>div{display:flex;align-items:center;gap:10px}
  .mobile-sticky img{width:75px;height:auto;object-fit:contain}
  .mobile-sticky small,.mobile-sticky strong{display:block;line-height:1.2}
  .mobile-sticky small{color:#7b8998;font-size:9px}
  .mobile-sticky strong{margin-top:3px;font-size:13px}
  .mobile-sticky>a{padding:11px 15px;color:#fff;background:var(--coral);font-size:13px;font-weight:900}
}
@media(prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  *,*::before,*::after{transition-duration:.01ms!important}
}