:root{--bg:#f5fbff;--white:#fff;--soft:#eaf7fc;--ice:#dff5fb;--cyan:#25c8d1;--sky:#25b6e8;--blue:#1787db;--deep:#174b78;--title:#173b60;--text:#2d4359;--muted:#687f93;--line:#dcebf3;--footer:#123653;--shadow:0 13px 35px rgba(23,75,120,.08)}
*{box-sizing:border-box}html{scroll-behavior:smooth}body{margin:0;background:var(--bg);color:var(--text);font:16px/1.8 Arial,"PingFang SC","Microsoft YaHei",sans-serif;-webkit-font-smoothing:antialiased}body.drawer-open{overflow:hidden}a{color:var(--blue);text-decoration:none}a:hover{color:var(--deep)}a:focus-visible,button:focus-visible{outline:3px solid var(--cyan);outline-offset:3px}button{font:inherit;cursor:pointer}img{max-width:100%}.container{width:min(1160px,calc(100% - 48px));margin-inline:auto}.skip-link{position:absolute;top:-90px;left:12px;background:#fff;padding:10px 16px;z-index:70}.skip-link:focus{top:8px}.site-header{position:sticky;top:0;z-index:40;background:rgba(255,255,255,.97);border-bottom:1px solid var(--line);backdrop-filter:blur(14px)}.header-shell{height:72px;display:flex;align-items:center;gap:22px}.brand{display:inline-flex;align-items:center;gap:9px;flex:none;color:var(--title)}.brand img{display:block;width:auto;max-width:175px;height:38px;object-fit:contain}.brand-mark{display:grid;place-items:center;width:39px;height:39px;border-radius:13px;background:linear-gradient(135deg,var(--cyan),var(--blue));color:#fff;font-weight:900;font-size:24px;line-height:1}.brand-word{font-weight:900;font-size:20px;line-height:1.15;white-space:nowrap}.brand-word small,.drawer-title small{display:block;font-size:9px;letter-spacing:1.7px;color:var(--muted);font-weight:700;margin-top:3px}.desktop-nav{display:flex;justify-content:center;align-items:center;gap:3px;flex:1}.nav-link{display:block;white-space:nowrap;color:var(--deep);font-size:14px;font-weight:650;padding:23px 10px 21px;border-bottom:3px solid transparent}.nav-link:hover,.nav-link.is-current{color:var(--blue)}.nav-link.is-current{border-color:var(--cyan)}.main-btn{display:inline-flex;align-items:center;justify-content:center;min-width:82px;height:42px;padding:0 20px;border-radius:999px;background:linear-gradient(110deg,#25c8d1,#25b6e8,#1787db);color:#fff;font-weight:700;line-height:1.2;text-decoration:none;white-space:nowrap;box-shadow:0 8px 18px rgba(23,135,219,.18)}.main-btn:hover{color:#fff;filter:brightness(1.07)}.menu-toggle{display:none;width:42px;height:42px;border:1px solid var(--line);background:#fff;border-radius:12px;padding:11px}.menu-toggle span{display:block;height:2px;background:var(--title);margin:4px 0;border-radius:3px}.drawer-backdrop{position:fixed;inset:0;background:rgba(7,31,52,.52);visibility:hidden;opacity:0;pointer-events:none;z-index:48;transition:opacity .2s,visibility .2s}.mobile-drawer{position:fixed;top:0;bottom:0;left:0;width:min(86vw,340px);overflow-y:auto;z-index:49;background:#fff;transform:translateX(-105%);visibility:hidden;box-shadow:10px 0 35px rgba(0,0,0,.1);transition:transform .25s,visibility .25s;padding:20px 21px 28px}.drawer-open .drawer-backdrop{visibility:visible;opacity:1;pointer-events:auto}.drawer-open .mobile-drawer{transform:translateX(0);visibility:visible}.drawer-head{display:flex;align-items:center;justify-content:space-between;padding-bottom:18px;border-bottom:1px solid var(--line)}.drawer-title{font-size:21px;font-weight:800;color:var(--title);line-height:1.1}.drawer-close{border:0;background:var(--soft);color:var(--deep);font-size:28px;width:36px;height:36px;border-radius:10px;line-height:1}.drawer-label{color:var(--blue);font-weight:750;font-size:12px;letter-spacing:1px;margin:22px 0 4px}.mobile-drawer>a{display:block;color:var(--title);padding:10px 8px;border-bottom:1px solid var(--line);font-size:15px}.mobile-drawer .drawer-home{margin-top:20px;color:var(--blue)}main{min-height:65vh}.section{padding-block:38px}.section-sm{padding-block:22px}.eyebrow{display:inline-flex;align-items:center;gap:9px;color:var(--blue);font-weight:850;letter-spacing:1.4px;font-size:12px;text-transform:uppercase}.eyebrow:before{content:"";width:22px;height:3px;background:var(--cyan);border-radius:10px}.hero{padding:45px 0 30px}.hero-grid{display:grid;grid-template-columns:minmax(0,1.08fr) minmax(0,.92fr);gap:35px;align-items:center}.hero h1{font-size:clamp(28px,3.6vw,40px);line-height:1.36;color:var(--title);margin:16px 0 19px;letter-spacing:-.6px}.hero p{font-size:17px;line-height:1.85;color:#49647b;max-width:580px}.hero-actions{display:flex;flex-wrap:wrap;gap:12px;margin-top:24px}.ghost-btn{display:inline-flex;align-items:center;padding:0 19px;height:42px;border:1px solid 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img{display:block;width:auto;height:auto;max-width:100%;max-height:100%;object-fit:contain;object-position:center}.media-placeholder{width:100%;height:100%;min-height:130px;display:flex;flex-direction:column;justify-content:center;align-items:center;gap:13px;padding:20px;color:#557e9c;text-align:center;font-size:13px;background:radial-gradient(circle at 72% 20%,#f8ffff 0,transparent 34%),linear-gradient(135deg,#e4f8ff,#d9eefa)}.placeholder-shape{display:block;width:67px;height:67px;border:5px solid #88d6ea;border-radius:18px;transform:rotate(-12deg);position:relative}.placeholder-shape:after{content:"";position:absolute;inset:13px;border-radius:50%;border:5px solid #afd9f2}.section-heading{display:flex;align-items:end;justify-content:space-between;gap:16px;margin-bottom:20px}.section-heading h2,.block-heading{font-size:clamp(21px,2.3vw,26px);color:var(--title);line-height:1.4;margin:7px 0 0}.section-heading p{margin:7px 0 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var(--line);border-radius:18px;background:#fff;padding:26px;box-shadow:var(--shadow)}.panel h3{color:var(--title);font-size:20px;line-height:1.4;margin:9px 0}.panel p{margin:10px 0;color:var(--text)}.article-list{padding:0;margin:0;list-style:none}.article-list li{padding:16px 0;border-bottom:1px solid var(--line)}.article-list li:first-child{padding-top:0}.article-list li:last-child{border:0;padding-bottom:0}.article-list a{font-weight:800;color:var(--title)}.article-list a:hover{color:var(--blue)}.article-list span{display:block;margin-top:5px;color:var(--muted);font-size:14px;line-height:1.65}.image-feature{display:grid;grid-template-columns:1fr 1fr;gap:22px;align-items:center;background:linear-gradient(115deg,#e7faff,#eaf3ff);border-radius:20px;padding:23px}.image-feature h3{font-size:22px;color:var(--title);margin:0 0 9px}.image-feature p{font-size:15px;margin:0 0 15px}.page-hero{padding:46px 0 26px;background:linear-gradient(135deg,#e6f8ff 0%,#f5fbff 65%);border-bottom:1px solid var(--line)}.page-hero .container{max-width:1160px}.page-hero h1{font-size:clamp(24px,3vw,34px);color:var(--title);line-height:1.43;margin:13px 0}.page-hero p{max-width:800px;color:#48647b;font-size:16px;margin:0}.breadcrumbs{font-size:13px;color:var(--muted);margin-bottom:8px}.breadcrumbs a{color:var(--blue)}.reading-wrap{max-width:860px;margin-inline:auto}.reading-wrap h2{color:var(--title);font-size:25px;line-height:1.4;margin:34px 0 12px}.reading-wrap h3{color:var(--deep);font-size:19px;line-height:1.45;margin:25px 0 8px}.reading-wrap p,.reading-wrap li{line-height:1.85}.reading-wrap p{margin:10px 0 17px}.lead{font-size:18px;color:#345d7d;border-left:4px solid var(--cyan);padding-left:18px}.note{background:#eaf7fc;border-left:3px solid var(--sky);padding:16px 20px;border-radius:0 12px 12px 0;margin-block:22px}.note strong{color:var(--title)}.two-cols{display:grid;grid-template-columns:1fr 1fr;gap:18px}.compare-card{background:#fff;border:1px solid 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p{color:#e6f7ff;margin:0;font-size:18px;line-height:1.7}.timeline{position:relative;margin:20px 0;padding-left:27px;border-left:2px solid #b7e8f3}.timeline-item{position:relative;margin:0 0 25px}.timeline-item:before{content:"";position:absolute;left:-34px;top:7px;width:12px;height:12px;border:3px solid var(--cyan);border-radius:50%;background:#fff}.timeline-item h3{margin:0 0 5px;color:var(--title)}.timeline-item p{margin:0}.related{margin-top:46px;padding:23px 0 0;border-top:1px solid var(--line)}.related h2{font-size:22px;color:var(--title);margin:0 0 16px}.related-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:12px}.related-link{display:flex;align-items:center;justify-content:space-between;gap:12px;background:#fff;border:1px solid var(--line);border-radius:12px;padding:14px;color:var(--deep);font-weight:700}.related-link:hover{border-color:var(--sky)}.figure-caption{font-size:13px;color:var(--muted);margin:8px 0 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h2{font-size:16px;color:#fff;margin:0 0 13px}.footer-nav{display:grid;grid-template-columns:1fr 1fr;gap:7px}.footer-nav a,.copyright a{color:#d4effa;font-size:13px}.copyright{padding:15px 0 22px;border-top:1px solid rgba(255,255,255,.14);font-size:12px;color:#abd0e4;display:flex;justify-content:space-between;gap:18px}.back-to-top{position:fixed;bottom:26px;right:20px;width:42px;height:42px;border:0;border-radius:12px;background:var(--blue);color:#fff;font-size:21px;box-shadow:var(--shadow);z-index:20;opacity:0;pointer-events:none;transition:opacity .2s}.back-to-top.is-visible{opacity:1;pointer-events:auto}.bottom-nav{display:none}
@media(max-width:1100px){.desktop-nav{gap:0}.nav-link{font-size:13px;padding-inline:7px}.header-shell{gap:13px}.brand-word{font-size:18px}}
@media(max-width:980px){.desktop-nav{display:none}.menu-toggle{display:block;flex:none}.header-shell{justify-content:space-between;height:61px}.brand{position:absolute;left:50%;transform:translateX(-50%)}.brand img{max-width:145px;height:30px}.brand-word{font-size:18px}.brand-mark{width:30px;height:30px;font-size:19px;border-radius:10px}.header-enter{height:39px;min-width:84px;padding:0 13px;font-size:13px}.hero{padding-top:27px}.hero-grid{gap:20px}.card-grid{grid-template-columns:repeat(2,minmax(0,1fr))}.footer-grid{gap:22px}}
@media(max-width:680px){body{font-size:15px}.container{width:calc(100% - 32px)}.hero-grid{display:flex;flex-direction:column-reverse;align-items:stretch;gap:18px}.hero-visual{padding:10px;border-radius:16px}.hero-visual .media--wide{max-height:225px}.hero h1{font-size:29px}.hero p{font-size:15px}.hero-meta{margin-top:16px}.section{padding-block:27px}.section-heading h2,.block-heading{font-size:22px}.section-heading{align-items:start}.card-grid,.feature-layout,.image-feature,.two-cols,.visual-grid,.stats-strip{grid-template-columns:1fr}.topic-card{padding:19px}.panel{padding:19px}.image-feature{padding:17px}.page-hero{padding:30px 0 22px}.page-hero h1{font-size:27px}.reading-wrap h2{font-size:21px;margin-top:27px}.reading-wrap h3{font-size:18px}.reading-wrap .lead{font-size:16px}.related-grid{grid-template-columns:1fr}.footer-grid{grid-template-columns:1fr;gap:22px;padding:30px 0}.copyright{flex-direction:column;gap:5px;padding-bottom:87px}.bottom-nav{position:fixed;z-index:35;bottom:0;left:0;right:0;display:grid;grid-template-columns:repeat(4,1fr);background:rgba(255,255,255,.98);box-shadow:0 -6px 20px rgba(20,70,110,.09);border-top:1px solid var(--line);padding-bottom:env(safe-area-inset-bottom)}.bottom-nav a{display:flex;flex-direction:column;align-items:center;justify-content:center;height:59px;font-size:11px;color:var(--muted);line-height:1.4}.bottom-nav a span{font-size:20px;line-height:1.3}.bottom-nav a[aria-current="page"]{color:var(--blue);font-weight:700}.back-to-top{bottom:77px;right:12px;width:37px;height:37px}.header-shell{height:60px}.menu-toggle{width:40px;height:40px}.brand img{max-width:112px;height:29px}.brand-word{font-size:16px}.brand-word small{font-size:7px}.header-enter{min-width:76px;padding:0 11px}.media--wide{max-height:220px}.media--portrait{max-height:320px}}
@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}*,*:before,*:after{transition:none!important;animation:none!important}}