:root{--bg:#f5fbff;--paper:#fff;--mist:#eaf7fc;--soft:#dff5fb;--cyan:#25c8d1;--sky:#25b6e8;--blue:#1787db;--ocean:#174b78;--ink:#173b60;--body:#2d4359;--muted:#687f93;--line:#dcebf3;--footer:#123653;--shadow:0 18px 60px rgba(21,84,126,.09)}
*,*::before,*::after{box-sizing:border-box}html{scroll-behavior:smooth;scroll-padding-top:88px}body{margin:0;font-family:Arial,"PingFang SC","Microsoft YaHei",sans-serif;background:var(--bg);color:var(--body);font-size:16px;line-height:1.8}button,input{font:inherit}a{color:inherit;text-decoration:none}a:hover{color:var(--blue)}a:focus-visible,button:focus-visible,summary:focus-visible{outline:3px solid var(--sky);outline-offset:3px}img{max-width:100%}.container{max-width:1160px;padding:0 24px;margin:auto}.reading-container{max-width:860px;margin-left:auto;margin-right:auto}.skip-link{position:absolute;left:12px;top:-100px;padding:8px 16px;background:var(--ink);color:white;z-index:100}.skip-link:focus{top:8px}.site-header{position:sticky;top:0;z-index:30;background:rgba(255,255,255,.97);border-bottom:1px solid var(--line);backdrop-filter:blur(14px)}.header-inner{height:72px;display:flex;align-items:center;gap:28px}.brand{display:inline-flex;align-items:center;flex-shrink:0;color:var(--ink);white-space:nowrap}.brand-logo{width:auto;height:36px;max-width:165px;object-fit:contain}.brand-wordmark{font-size:23px;font-weight:900;letter-spacing:.02em;color:var(--ocean);line-height:1.2}.brand-orb{display:inline-grid;place-items:center;width:31px;height:31px;border-radius:50%;background:linear-gradient(130deg,var(--cyan),var(--blue));color:white;margin-right:5px}.desktop-nav{display:flex;align-items:center;gap:22px;margin-left:auto}.desktop-nav a{font-size:14px;font-weight:700;color:var(--ocean);line-height:72px;white-space:nowrap;border-bottom:3px solid transparent}.desktop-nav a:hover,.desktop-nav a.current{color:var(--blue);border-bottom-color:var(--cyan)}.main-btn{display:inline-flex;align-items:center;justify-content:center;gap:7px;min-width:82px;min-height:42px;padding:0 20px;border-radius:999px;background:linear-gradient(110deg,#25c8d1,#25b6e8,#1787db);color:#fff;font-weight:700;text-decoration:none;white-space:nowrap;box-shadow:0 10px 25px rgba(23,135,219,.2)}.main-btn:hover{color:white;filter:brightness(1.05);transform:translateY(-1px)}.header-cta{font-size:13px}.menu-toggle{display:none;background:none;border:0;width:42px;height:42px;align-items:center;justify-content:center;flex-direction:column;gap:5px;cursor:pointer}.menu-toggle span{width:22px;height:2px;background:var(--ocean);border-radius:3px}.menu-overlay{visibility:hidden;pointer-events:none;position:fixed;inset:0;background:rgba(7,31,52,.48);z-index:35;opacity:0;transition:opacity .22s,visibility .22s}.mobile-menu{position:fixed;top:0;left:0;bottom:0;width:min(86vw,340px);background:white;z-index:36;transform:translateX(-105%);visibility:hidden;pointer-events:none;overflow-y:auto;padding:20px 22px 40px;transition:transform .22s,visibility .22s;box-shadow:var(--shadow)}.menu-open{overflow:hidden}.menu-open .menu-overlay{visibility:visible;pointer-events:auto;opacity:1}.menu-open .mobile-menu{visibility:visible;pointer-events:auto;transform:translateX(0)}.drawer-top{display:flex;justify-content:space-between;align-items:center;padding-bottom:18px;border-bottom:1px solid var(--line)}.drawer-close{border:0;background:var(--mist);color:var(--ink);font-size:28px;width:39px;height:39px;border-radius:50%;cursor:pointer}.drawer-group{padding:16px 0;border-bottom:1px solid var(--line)}.drawer-group p{font-size:12px;font-weight:800;letter-spacing:.1em;color:var(--blue);margin:0 0 7px}.drawer-group a{display:block;font-size:15px;padding:6px 2px;font-weight:600}.bottom-nav{display:none}.back-to-top{position:fixed;right:26px;bottom:24px;z-index:24;width:44px;height:44px;border:0;border-radius:50%;background:var(--blue);color:white;cursor:pointer;opacity:0;visibility:hidden;transition:.2s;box-shadow:var(--shadow)}.back-to-top.visible{opacity:1;visibility:visible}
h1,h2,h3{color:var(--ink);line-height:1.38;margin:0 0 16px;letter-spacing:-.025em}h1{font-size:36px}h2{font-size:25px}h3{font-size:19px}p{margin:0 0 16px}.eyebrow{display:inline-block;font-size:12px;font-weight:900;letter-spacing:.18em;color:#167fac;margin-bottom:9px}.lead{font-size:17px;color:#4a6780;line-height:1.85}.section{padding:48px 0}.section-muted{background:#eff9fe;border-top:1px solid var(--line);border-bottom:1px solid var(--line)}.section-heading{margin:0 0 24px}.section-heading h2{margin:0}.section-heading p{margin:9px 0 0;color:var(--muted)}.hero{padding:66px 0 45px;position:relative;overflow:hidden;background:radial-gradient(circle at 75% 20%,#c9f4fc 0%,transparent 41%),linear-gradient(130deg,#f5fbff,#e9f8ff)}.hero-grid{display:grid;grid-template-columns:1.1fr .9fr;gap:56px;align-items:center}.hero h1{font-size:40px;max-width:650px;margin-bottom:20px}.hero .lead{max-width:600px}.hero-actions{display:flex;gap:15px;flex-wrap:wrap;margin-top:26px}.subtle-link{display:inline-flex;align-items:center;min-height:42px;padding:0 12px;font-weight:700;color:var(--ocean)}.hero-mini{display:flex;gap:18px;flex-wrap:wrap;margin-top:34px;padding-top:20px;border-top:1px solid #cfebf5;color:var(--ocean);font-size:13px;font-weight:700}.hero-mini span:before{content:'•';color:var(--cyan);padding-right:7px}.media{width:100%;min-height:170px;display:flex;align-items:center;justify-content:center;border-radius:18px;overflow:hidden;background:var(--mist)}.media img{display:block;width:auto;height:auto;max-width:100%;max-height:100%;object-fit:contain;object-position:center}.media-empty{position:relative;background:linear-gradient(135deg,#dff5fb,#a8e4f4 55%,#beeaf8);border:1px solid #c1ebf5}.media-empty::before,.media-empty::after{content:'';position:absolute;border:1px solid rgba(255,255,255,.65);border-radius:50%;width:58%;aspect-ratio:1;right:-10%;top:-45%}.media-empty::after{width:44%;left:-13%;top:auto;bottom:-60%}.media-shape{width:36%;aspect-ratio:1;border:20px solid rgba(255,255,255,.4);border-radius:50%;box-shadow:0 0 0 26px rgba(23,135,219,.04)}.media-hero{height:330px}.media-landscape{height:230px}.media-card{height:174px}.media-portrait{height:330px;max-width:320px}.media-short{height:200px}.card-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:20px}.card{display:flex;flex-direction:column;background:white;border:1px solid var(--line);border-radius:17px;overflow:hidden;box-shadow:0 9px 26px rgba(21,84,126,.035)}.card:hover{border-color:#aedcea;transform:translateY(-2px);transition:.18s}.card-body{padding:22px;flex:1}.card .eyebrow{margin-bottom:8px}.card h3{margin:0 0 9px}.card p{font-size:14px;color:var(--muted);line-height:1.8}.card .read-more{font-size:13px;color:var(--blue);font-weight:800}.card-body .read-more{display:inline-block;margin-top:7px}.feature-split{display:grid;grid-template-columns:1fr 1fr;gap:46px;align-items:center}.feature-split.reverse .media{order:-1}.feature-copy ul,.article ul{padding-left:23px}.feature-copy li,.article li{margin-bottom:9px}.feature-copy p{color:var(--body)}.topic-list{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:14px}.topic-list a,.related-link{display:flex;align-items:center;justify-content:space-between;gap:12px;padding:18px 20px;background:white;border:1px solid var(--line);border-radius:12px;font-weight:800;color:var(--ocean)}.topic-list a:hover,.related-link:hover{background:#eaf8ff;border-color:#a1dbe9;color:var(--blue)}.topic-list small{display:block;color:var(--muted);font-weight:400;font-size:12px;margin-top:3px}.pill{display:inline-block;background:#dff5fb;color:#167fac;border-radius:99px;padding:3px 11px;font-size:12px;font-weight:800}.number-line{display:flex;gap:15px;align-items:start;border-bottom:1px solid var(--line);padding:18px 0}.number-line b{color:var(--blue);font-size:22px;line-height:1.3;min-width:40px}.number-line h3{margin:0 0 5px}.number-line p{margin:0;font-size:14px;color:var(--muted)}.page-intro{padding:57px 0 39px;background:linear-gradient(125deg,#f4fcff,#e6f7fd);border-bottom:1px solid var(--line)}.page-intro h1{font-size:34px;max-width:900px}.page-intro .lead{max-width:790px;margin-bottom:0}.breadcrumbs{font-size:12px;font-weight:700;color:var(--muted);margin-bottom:21px}.breadcrumbs a{color:var(--blue)}.article{max-width:820px;margin:auto;font-size:16px;line-height:1.83}.article>section{margin-bottom:42px}.article h2{margin-top:0;padding-bottom:12px;border-bottom:1px solid var(--line)}.article h3{margin-top:25px}.article blockquote{border-left:4px solid var(--cyan);background:#e9f9fd;padding:20px 25px;margin:20px 0;border-radius:0 12px 12px 0;color:var(--ocean);font-weight:700}.article .media{margin:22px 0}.article p{margin-bottom:17px}.highlight-panel{background:linear-gradient(125deg,#e5f8fc,#f5fbff);border:1px solid #c5e9f3;border-radius:16px;padding:27px}.highlight-panel h3{margin-top:0}.compare-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:20px}.compare-box{padding:25px;background:#fff;border:1px solid var(--line);border-radius:15px}.compare-box h3{margin:0 0 12px}.compare-box p{margin:0 0 10px}.scroll-table{overflow-x:auto;margin:22px 0;border:1px solid var(--line);border-radius:14px}table{width:100%;border-collapse:collapse;text-align:left;min-width:570px}th{background:#e2f5fb;color:var(--ocean);font-size:14px}td,th{border-bottom:1px solid var(--line);padding:14px 17px;vertical-align:top}tr:last-child td{border-bottom:0}td{font-size:14px}.insight-row{display:grid;grid-template-columns:100px 1fr;gap:22px;border-bottom:1px solid var(--line);padding:23px 0}.insight-row .index{font-size:28px;font-weight:900;color:var(--sky)}.insight-row h3{margin-bottom:8px}.tags{display:flex;flex-wrap:wrap;gap:8px;margin:15px 0}.tags span{font-size:12px;padding:3px 10px;background:#dff5fb;color:var(--ocean);border-radius:50px}.related{padding:22px 0 65px}.related-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:11px}.footer-inner{display:grid;grid-template-columns:2fr 1fr 1fr;gap:60px;padding-top:55px;padding-bottom:35px}.site-footer{background:var(--footer);color:#eaf7ff}.site-footer .brand-wordmark{color:white}.footer-brand p{font-size:13px;opacity:.8;max-width:380px;margin:12px 0 0}.footer-links h2{font-size:15px;color:white;margin:0 0 15px}.footer-links a{display:block;font-size:13px;color:#d7effa;margin:5px 0}.footer-links a:hover{color:white}.footer-bottom{border-top:1px solid rgba(255,255,255,.14);padding-top:18px;padding-bottom:26px;display:flex;gap:20px;justify-content:space-between;flex-wrap:wrap;font-size:12px;opacity:.7}.faq-list details{border-bottom:1px solid var(--line);padding:16px 0}.faq-list summary{cursor:pointer;font-weight:800;color:var(--ink)}.faq-list details p{font-size:14px;margin:10px 0 0}.notice{font-size:13px;color:var(--muted);border-left:3px solid var(--sky);padding:10px 15px;background:#eef9fe}
@media(max-width:1080px){.desktop-nav{gap:11px}.header-inner{gap:16px}.brand-wordmark{font-size:19px}.desktop-nav a{font-size:12px}}@media(max-width:980px){.desktop-nav{display:none}.menu-toggle{display:flex}.brand{margin:0 auto}.header-inner{justify-content:space-between;height:60px}.brand-logo{height:29px;max-width:135px}.brand-wordmark{font-size:19px}.header-cta{min-height:39px;padding:0 13px;font-size:12px}.bottom-nav{display:flex;position:fixed;bottom:0;left:0;right:0;z-index:29;background:white;border-top:1px solid var(--line);padding:8px 8px max(7px,env(safe-area-inset-bottom));justify-content:space-around}.bottom-nav a{display:flex;flex-direction:column;text-align:center;font-size:11px;color:var(--ocean);font-weight:700;line-height:1.4;min-width:55px}.bottom-nav span{font-size:19px;color:var(--blue);line-height:1.15}.footer-bottom{padding-bottom:90px}.back-to-top{bottom:83px;right:16px}.hero-grid{gap:25px}.hero h1{font-size:35px}}@media(max-width:700px){.container{padding:0 16px}.section{padding:32px 0}.hero{padding:33px 0 36px}.hero-grid{display:flex;flex-direction:column-reverse;gap:25px;align-items:stretch}.hero h1{font-size:29px}.lead{font-size:15px}.hero-mini{margin-top:22px;gap:10px}.media-hero{height:190px}.media-landscape{height:180px}.media-card{height:148px}.media-short{height:165px}.media-portrait{height:280px}.card-grid,.feature-split,.compare-grid{grid-template-columns:1fr}.card-grid{gap:14px}.feature-split{gap:23px}.topic-list,.related-grid{grid-template-columns:1fr}.page-intro{padding:32px 0}.page-intro h1{font-size:27px}.article{font-size:15px}.article>section{margin-bottom:30px}h2{font-size:21px}h3{font-size:18px}.article h3{font-size:17px}.section-heading{margin-bottom:20px}.footer-inner{grid-template-columns:1fr 1fr;gap:25px;padding-top:35px}.footer-brand{grid-column:1/-1}.footer-bottom{display:block}.footer-bottom span{display:block;margin:6px 0}.insight-row{grid-template-columns:54px 1fr;gap:9px}.insight-row .index{font-size:21px}.highlight-panel{padding:19px}.hero-actions{margin-top:15px}.main-btn{min-height:40px}.related{padding-bottom:36px}}@media(max-width:370px){.header-cta{min-width:auto;padding:0 9px}.header-cta span{display:none}.brand-wordmark{font-size:16px}.brand-orb{width:25px;height:25px}.header-inner{gap:6px}}@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}*,*::before,*::after{transition:none!important;animation:none!important}}