:root{--base:#F6FAFC;--surface:#FFF;--sky:#EAF6FA;--soft:#EDF4F8;--cyan:#25C8D1;--blue:#1787DB;--deep:#174B78;--heading:#183A56;--text:#31485D;--muted:#687D8E;--line:#DCE9F0;--footer:#123653;--radius:16px}*{box-sizing:border-box}html{scroll-behavior:smooth;scroll-padding-top:24px}body{margin:0;background:var(--base);color:var(--text);font:16px/1.8 Arial,'PingFang SC','Microsoft YaHei',sans-serif;overflow-x:hidden}body.drawer-open{overflow:hidden}a{color:#1165A7;text-underline-offset:4px}a:hover{color:#137EB7}button{font:inherit}a:focus-visible,button:focus-visible,summary:focus-visible{outline:3px solid #00A5B6;outline-offset:4px;border-radius:4px}.container{width:min(100% - 56px,1180px);margin-inline:auto}.skip-link{position:absolute;top:-100px;left:12px;z-index:100;padding:10px 16px;background:#fff}.skip-link:focus{top:8px}.site-header{background:#fff;border-bottom:1px solid var(--line);position:relative;z-index:30}.topbar{display:flex;align-items:center;height:72px;gap:20px}.brand{display:flex;align-items:center;text-decoration:none;min-width:0}.brand .media{height:38px;min-width:115px;max-width:235px;background:transparent;border:0}.brand .media img{max-height:38px;max-width:235px}.brand-fallback{display:none;color:var(--deep);font-weight:900;letter-spacing:1px;white-space:nowrap}.brand .media:has(.media__placeholder){display:none}.brand .media:has(.media__placeholder)+.brand-fallback{display:block}.brand-descriptor{flex:1;margin:0;text-align:center;font-size:14px;color:var(--muted);letter-spacing:2px}.brand-descriptor i{font-style:normal;color:var(--cyan)}.entry-button{display:inline-flex;align-items:center;justify-content:center;gap:7px;min-height:42px;background:var(--deep);color:#fff;font-weight:700;padding:7px 19px;border-radius:9px;white-space:nowrap;text-decoration:none;font-size:14px}.entry-button:hover{background:#0E6592;color:#fff}.desktop-nav{background:var(--deep)}.nav-links{display:flex;justify-content:space-between;gap:10px}.nav-links a{padding:11px 13px 10px;min-height:48px;color:#edfaff;text-decoration:none;font-size:15px;font-weight:600;white-space:nowrap;border-bottom:3px solid transparent}.nav-links a:hover{background:#245F8B}.nav-links a[aria-current=page]{border-color:#6FE4E9;background:#22638E;color:#fff}.menu-toggle{display:none}.quickbar{background:#eaf6fa;border-bottom:1px solid var(--line)}.quickbar-inner{display:flex;gap:22px;flex-wrap:wrap;align-items:center;padding-block:12px;font-size:13px}.quickbar-inner span{font-weight:700;color:var(--deep);white-space:nowrap}.quickbar-inner a{margin-left:11px;font-weight:400}.main-content{padding-block:36px 72px}.section{margin-block:54px}.section-heading{margin-bottom:23px}.section-heading 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20px;border-radius:10px;font-weight:700;text-decoration:none;background:var(--deep);color:#fff}.action:hover{color:#fff;background:#11649B}.action--outline{background:#eaf6fa;color:var(--deep);border:1px solid #b8dfea}.action--outline:hover{color:var(--deep);background:#dff4f6}.media{display:flex;justify-content:center;align-items:center;width:100%;min-width:0;overflow:hidden;border-radius:14px;background:var(--sky);border:1px solid #d9edf3}.media img{display:block;width:auto;height:auto;max-width:100%;max-height:100%;object-fit:contain;object-position:center}.media--hero{height:clamp(250px,26vw,330px)}.media--feature{height:250px}.media--card{height:170px}.media--banner{height:220px}.media--mobile{height:350px;max-width:320px;margin:auto}.media--logo{border:0;background:transparent}.media__placeholder{display:block;width:100%;height:100%;background:linear-gradient(135deg,#edf7fa,#d9ecf4)}.media--logo .media__placeholder{background:none}.topic-grid{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:14px}.topic{display:flex;flex-direction:column;min-width:0;background:#fff;border:1px solid var(--line);border-radius:14px;padding:21px 21px 19px;text-decoration:none;transition:border-color .2s,transform .2s}.topic:hover{border-color:#7acbd9;transform:translateY(-2px)}.topic strong{font-size:18px;color:var(--heading)}.topic span{color:var(--muted);font-size:14px;margin-top:7px;line-height:1.7}.topic em{font-style:normal;color:#067B9A;margin-top:auto;padding-top:12px;font-size:13px;font-weight:700}.feature-layout{display:grid;grid-template-columns:2fr 1fr;gap:20px}.panel{background:#fff;border:1px solid var(--line);border-radius:16px;padding:26px;min-width:0}.panel--soft{background:var(--sky)}.panel--dark{background:var(--deep);color:#ebf8ff;border-color:var(--deep)}.panel--dark h3,.panel--dark h2{color:#fff}.panel--dark a{color:#d7f9ff}.stack{display:grid;gap:18px}.kicker{font-size:12px;text-transform:uppercase;letter-spacing:1.6px;color:#0785A7;font-weight:800;margin-bottom:11px}.feature-layout .panel:first-child{padding:34px}.feature-layout .panel:first-child h3{font-size:24px}.linkline{display:inline-block;margin-top:16px;font-weight:700}.split-section{display:grid;grid-template-columns:1fr 1fr;align-items:center;gap:36px}.split-section.reverse .media{order:-1}.split-section .copy{max-width:600px}.split-section .copy p{margin:0 0 15px}.mini-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:16px}.mini-card{padding:23px;border:1px solid var(--line);background:#fff;border-radius:14px}.mini-card h3{font-size:19px}.steps{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:12px;counter-reset:step}.step{border-top:3px solid #28b8c9;background:#fff;border-radius:4px 4px 12px 12px;padding:22px;min-width:0}.step b{display:block;color:#0e86a2;font-size:13px;margin-bottom:8px}.step h3{font-size:18px}.editor-note{border-left:4px solid #27baca;padding:14px 22px;background:#eaf6fa;border-radius:0 10px 10px 0;margin-top:46px;color:#455d70}.article{max-width:780px}.prose{font-size:16.5px;line-height:1.85}.prose h2{margin-top:34px}.prose p{margin-bottom:17px}.prose ul,.prose ol{padding-left:1.5em}.prose li{margin-bottom:9px}.article-grid{display:grid;grid-template-columns:minmax(0,780px) minmax(215px,1fr);gap:35px;align-items:start}.sidebar{position:sticky;top:25px;background:#eaf6fa;border-radius:13px;padding:22px}.sidebar h2{font-size:20px}.sidebar p{font-size:14px}.section-contrast{padding:32px;background:#eaf6fa;border-radius:16px}.comparison,.table-wrap{overflow-x:auto;max-width:100%}table{border-collapse:collapse;width:100%;min-width:520px;background:#fff}caption{text-align:left;font-weight:700;color:var(--heading);padding:0 0 10px}th,td{padding:13px 16px;text-align:left;vertical-align:top;border-bottom:1px solid var(--line);font-size:15px}th{background:#e4f2f7;color:var(--heading);font-weight:700}tbody tr:last-child td,tbody tr:last-child th{border-bottom:0}.matrix{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:16px}.matrix .panel{border-top:4px solid var(--cyan)}.number-list{list-style:none;counter-reset:count;padding:0;margin:20px 0;display:grid;gap:13px}.number-list li{counter-increment:count;position:relative;background:white;padding:17px 20px 17px 66px;border:1px solid var(--line);border-radius:12px}.number-list li:before{content:counter(count,decimal-leading-zero);position:absolute;left:20px;top:17px;color:#0694a3;font-weight:800}.gallery{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:20px}.gallery figure{margin:0;background:#fff;border:1px solid var(--line);padding:15px;border-radius:14px}.gallery figcaption{padding:15px 6px 3px;font-size:14px;color:var(--muted)}.gallery figcaption strong{display:block;font-size:18px;color:var(--heading);margin-bottom:5px}.chapter-nav{display:flex;flex-wrap:wrap;gap:10px;margin:23px 0}.chapter-nav a{background:#e1f4f7;border-radius:8px;padding:8px 15px;font-weight:700;text-decoration:none}.faq-list{display:grid;gap:10px;margin-top:18px}.faq-list details{background:#fff;border:1px solid var(--line);border-radius:10px;padding:0 20px}.faq-list summary{cursor:pointer;font-weight:700;color:var(--heading);padding:15px 5px}.faq-list details p{padding:0 5px 17px;color:var(--text)}.related-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:15px}.related-item{display:flex;flex-direction:column;position:relative;padding:22px 40px 22px 21px;border-radius:12px;background:#fff;border:1px solid var(--line);text-decoration:none}.related-item strong{color:var(--heading);font-size:17px}.related-item span:not(.arrow){color:var(--muted);font-size:14px;margin-top:7px;line-height:1.7}.related-item .arrow{position:absolute;right:16px;top:21px;color:#0792a8}.site-footer{background:var(--footer);color:#eaf7ff;padding-top:40px}.footer-grid{display:grid;grid-template-columns:2fr 1fr;gap:60px}.footer-brand{font-size:21px;font-weight:800}.footer-brand small{display:block;font-size:12px;font-weight:500;letter-spacing:1.4px}.footer-disclaimer{max-width:680px;font-size:13px;color:#c9deec}.site-footer h2{font-size:17px;color:#fff}.footer-links{display:grid;grid-template-columns:1fr 1fr;gap:5px 15px}.footer-links a,.footer-bottom a{color:#e3f5fd;font-size:14px}.footer-bottom{border-top:1px solid #37607d;margin-top:35px;padding:14px 0;display:flex;justify-content:space-between;gap:20px}.mobile-bottom,.mobile-drawer,.drawer-overlay{display:none}.back-top{position:fixed;right:22px;bottom:24px;width:43px;height:43px;border-radius:50%;border:0;background:var(--deep);color:#fff;cursor:pointer;opacity:0;visibility:hidden;transition:opacity .2s,visibility .2s;z-index:20}.back-top.is-visible{opacity:1;visibility:visible}
@media(max-width:980px){.container{width:min(100% - 44px,1180px)}.desktop-nav{display:none}.brand-descriptor{display:none}.topbar{height:64px;justify-content:space-between}.menu-toggle{display:flex;flex-direction:column;justify-content:center;gap:5px;align-items:center;width:40px;height:40px;border:1px solid var(--line);background:#fff;border-radius:8px;cursor:pointer;flex-shrink:0}.menu-toggle span{display:block;width:19px;height:2px;background:var(--deep)}.brand .media{height:30px;max-width:165px;min-width:65px}.brand .media img{max-height:30px;max-width:165px}.brand-fallback{font-size:13px}.entry-button{min-height:40px;font-size:13px;padding:7px 13px}.mobile-drawer{display:block;position:fixed;z-index:61;inset:0 auto 0 0;width:min(86vw,344px);background:#fff;box-shadow:6px 0 22px #163e5b25;transform:translateX(-105%);transition:transform .22s ease;overflow-y:auto;visibility:hidden}.drawer-overlay{display:block;position:fixed;inset:0;background:rgba(8,28,43,.48);z-index:60;opacity:0;visibility:hidden;pointer-events:none;transition:opacity .22s,visibility .22s}.drawer-open .mobile-drawer{transform:translateX(0);visibility:visible}.drawer-open .drawer-overlay{opacity:1;visibility:visible;pointer-events:auto}.drawer-head{display:flex;justify-content:space-between;align-items:center;padding:19px 22px;border-bottom:1px solid var(--line);font-weight:800;color:var(--deep);letter-spacing:1px}.drawer-close{width:40px;height:40px;background:#f1f7fa;border:0;border-radius:7px;font-size:28px;cursor:pointer}.drawer-group{padding:16px 22px 10px}.drawer-group p{color:var(--muted);font-size:12px;font-weight:800;letter-spacing:1px;margin-bottom:5px}.drawer-group a{display:flex;justify-content:space-between;align-items:center;padding:11px 2px;text-decoration:none;font-weight:700;color:var(--heading);border-bottom:1px solid #eaf0f4}.drawer-group a[aria-current=page]{color:#008c9f}.topic-grid{grid-template-columns:repeat(2,minmax(0,1fr))}.hero{padding:30px}.hero h1{font-size:35px}.quickbar-inner{gap:8px 20px}}
@media(max-width:760px){.main-content{padding-block:25px 65px}.section{margin-block:38px}.section-heading h2{font-size:23px}.hero,.feature-layout,.split-section,.article-grid,.footer-grid{grid-template-columns:1fr}.hero{gap:23px}.hero>.media{order:-1}.split-section.reverse .media{order:0}.mini-grid,.matrix{grid-template-columns:1fr 1fr}.steps{grid-template-columns:1fr 1fr}.sidebar{position:static}.footer-grid{gap:25px}.page-intro h1{font-size:29px}.quickbar-inner span{white-space:normal}.gallery{gap:12px}.related-grid{grid-template-columns:1fr}.mobile-bottom{display:flex;position:fixed;bottom:0;left:0;right:0;z-index:22;background:#fff;border-top:1px solid var(--line);padding:7px 0 calc(7px + env(safe-area-inset-bottom));box-shadow:0 -5px 15px #163e5b0c}.mobile-bottom a{flex:1;text-align:center;text-decoration:none;font-size:13px;font-weight:700;padding:4px;color:var(--text)}.mobile-bottom a[aria-current=page]{color:#008e9e;text-decoration:underline}.site-footer{padding-bottom:63px}.back-top{bottom:78px}}
@media(max-width:640px){body{font-size:15px;line-height:1.78}.container{width:calc(100% - 32px)}.hero{padding:19px;border-radius:14px}.hero h1{font-size:29px;margin:7px 0 13px}.lede{font-size:15.5px}.hero-actions{gap:8px}.action{padding:9px 13px;font-size:13px}.page-intro h1{font-size:27px}.page-intro{margin-bottom:22px}.section-heading h2,h2{font-size:22px}h3{font-size:18px}.topic-grid{grid-template-columns:1fr 1fr;gap:9px}.topic{padding:15px}.topic strong{font-size:16px}.topic span{font-size:13px}.feature-layout .panel:first-child,.panel{padding:19px}.mini-grid,.matrix,.gallery{grid-template-columns:1fr}.steps{grid-template-columns:1fr 1fr;gap:8px}.step{padding:16px}.step h3{font-size:16px}.media--hero{height:200px}.media--feature{height:180px}.media--card{height:145px}.media--banner{height:150px}.media--mobile{height:290px;max-width:250px}.quickbar-inner{padding-block:9px;display:grid;gap:4px;font-size:12px}.quickbar-inner a{margin-left:9px}.prose{font-size:15.5px}.section-contrast{padding:20px}.topbar{gap:8px}.brand .media{max-width:120px;min-width:40px}.brand .media img{max-width:120px}.entry-button{padding:7px 9px;font-size:12px}.entry-button span{display:none}.footer-links{gap:5px}.footer-bottom{font-size:11px;flex-wrap:wrap}}
@media(max-height:480px) and (max-width:760px){.mobile-bottom{position:static}.site-footer{padding-bottom:0}.back-top{bottom:20px}}@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}*,*:before,*:after{transition:none!important;animation:none!important}}