:root{--bg:#F6FAFC;--surface:#fff;--pale:#EAF6FA;--pale2:#EDF4F8;--cyan:#25C8D1;--sky:#25B6E8;--blue:#1787DB;--deep:#174B78;--heading:#183A56;--body:#31485D;--muted:#687D8E;--line:#DCE9F0;--footer:#123653;--wrap:1180px}
*{box-sizing:border-box}html{scroll-behavior:smooth;scroll-padding-top:26px}body{margin:0;background:var(--bg);color:var(--body);font-family:Arial,"PingFang SC","Microsoft YaHei",sans-serif;font-size:16px;line-height:1.8}body.drawer-open{overflow:hidden}img{max-width:100%}a{color:var(--deep);text-underline-offset:4px}a:hover{color:var(--blue)}button{font:inherit;cursor:pointer}button,a,summary{outline-offset:3px}a:focus-visible,button:focus-visible,summary:focus-visible{outline:3px solid var(--cyan)}h1,h2,h3{color:var(--heading);line-height:1.38;margin:0 0 .7em}h1{font-size:clamp(2rem,3vw,2.65rem);letter-spacing:-.025em}h2{font-size:clamp(1.45rem,2.1vw,1.7rem)}h3{font-size:1.24rem}p{margin:.65em 0 1.15em}ul,ol{padding-left:1.5em}li+li{margin-top:.3em}.wrap{width:min(var(--wrap),calc(100% - 56px));margin-inline:auto}.skip-link{position:absolute;left:12px;top:-100px;background:#fff;padding:12px;z-index:200}.skip-link:focus{top:10px}.site-header{background:#fff;position:relative;z-index:21;border-bottom:1px solid var(--line)}.topbar{height:72px;display:flex;align-items:center;gap:20px}.brand{display:inline-flex;align-items:center;text-decoration:none;color:var(--deep);min-width:0}.brand img{display:block;width:auto;height:auto;max-height:38px;max-width:230px;object-fit:contain}.brand-type{font-weight:800;font-size:23px;line-height:1.1;white-space:nowrap}.brand-type small,.footer-brand small{font-size:10px;font-weight:700;letter-spacing:.13em;display:block}.topbar-caption{margin:0 auto;color:var(--muted);font-size:13px;letter-spacing:.13em}.entry-button{background:linear-gradient(115deg,#1787DB,#1686B8);color:#fff;text-decoration:none;font-weight:700;font-size:14px;padding:10px 21px;border-radius:9px;white-space:nowrap}.entry-button:hover{color:#fff;background:var(--deep)}.desktop-navigation{background:var(--deep)}.nav-items{display:flex;align-items:center;justify-content:space-between;gap:9px}.nav-items a{color:#EAF7FF;text-decoration:none;padding:12px 9px 11px;font-size:14px;white-space:nowrap;border-bottom:3px solid transparent;line-height:1.5}.nav-items a:hover,.nav-items a[aria-current=page]{color:#fff;border-bottom-color:var(--cyan);font-weight:700}.menu-toggle{display:none;border:1px solid var(--line);background:#fff;width:40px;height:40px;border-radius:9px;align-items:center;justify-content:center;flex-direction:column;gap:5px;flex-shrink:0}.menu-toggle span{width:18px;height:2px;background:var(--deep);border-radius:1px}.drawer-backdrop{position:fixed;inset:0;background:#0f304d80;z-index:39;opacity:0;visibility:hidden;pointer-events:none;transition:opacity .2s,visibility .2s}.drawer-backdrop.is-open{visibility:visible;opacity:1;pointer-events:auto}.mobile-drawer{position:fixed;inset:0 auto 0 0;width:min(86vw,344px);background:white;z-index:40;overflow-y:auto;transform:translateX(-104%);visibility:hidden;pointer-events:none;transition:transform .24s,visibility .24s;box-shadow:8px 0 34px #1e466225}.mobile-drawer.is-open{transform:translateX(0);visibility:visible;pointer-events:auto}.drawer-heading{display:flex;align-items:center;justify-content:space-between;padding:20px;border-bottom:1px solid var(--line);color:var(--deep)}.drawer-heading button{background:transparent;border:0;font-size:30px;line-height:1}.drawer-group{padding:16px 20px;border-bottom:1px solid var(--line)}.drawer-group b{display:block;color:var(--muted);font-size:12px;letter-spacing:.1em;margin-bottom:8px}.drawer-group a{display:block;padding:8px 2px;text-decoration:none;font-weight:600}.quicklinks{background:#EDF4F8;border-bottom:1px solid var(--line)}.quicklinks .wrap{display:flex;align-items:center;justify-content:space-between;gap:16px;padding-top:11px;padding-bottom:11px}.quick-group{display:flex;flex-wrap:wrap;gap:10px;font-size:13px}.quick-group b{color:var(--deep)}.quick-group a{text-decoration:none;color:#40647E}.quick-group a:hover{text-decoration:underline}.home-hero{background:linear-gradient(110deg,#F8FCFD,#EAF6FA);padding:54px 0 44px}.hero-grid{display:grid;grid-template-columns:56fr 44fr;gap:34px;align-items:center;min-width:0}.hero-grid>*{min-width:0}.eyebrow{color:#087F9B;text-transform:uppercase;font-size:12px;letter-spacing:.15em;font-weight:800;display:block;margin-bottom:14px}.hero-copy h1{font-size:clamp(32px,3.4vw,42px);margin:0 0 18px}.hero-copy p{max-width:610px;font-size:16px;line-height:1.85}.actions{display:flex;flex-wrap:wrap;gap:12px;margin-top:23px}.action-primary,.action-secondary{padding:10px 19px;font-size:14px;border-radius:8px;text-decoration:none;font-weight:700;display:inline-flex;align-items:center;min-height:43px}.action-primary{color:#fff;background:var(--deep)}.action-primary:hover{color:#fff;background:var(--blue)}.action-secondary{background:#fff;border:1px solid #BDD8E6}.media{display:flex;align-items:center;justify-content:center;width:100%;min-width:0;margin:0;overflow:hidden;border-radius:14px;background:var(--pale)}.media img{display:block;width:auto;height:auto;max-width:100%;max-height:100%;object-fit:contain;object-position:center}.media-placeholder{width:62%;height:58%;border:1px solid #CEE2EB;border-radius:12px;background:linear-gradient(135deg,#e9f8fa,#daeaf2);display:block}.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}.media--portrait{max-width:340px;margin-inline:auto}.media--wide{background:#f1f8fa}.section{padding:57px 0}.section-heading{max-width:800px;margin-bottom:25px}.section-heading h2{margin-bottom:9px}.section-heading p{color:var(--muted);margin:0}.section--tint{background:var(--pale2)}.topic-grid{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:14px}.topic-card{background:#fff;border:1px solid var(--line);border-radius:12px;padding:22px;display:block;text-decoration:none;min-width:0;transition:border-color .2s,transform .2s}.topic-card:hover{border-color:#75ccd8;transform:translateY(-2px)}.topic-card .num{font-size:12px;color:#0B96A3;font-weight:800;letter-spacing:.06em}.topic-card h3{margin:9px 0 8px;font-size:18px}.topic-card p{font-size:14px;color:var(--muted);margin:0}.topic-card .more{display:block;margin-top:15px;font-size:13px;font-weight:700;color:var(--deep)}.editorial-grid{display:grid;grid-template-columns:2fr 1fr;gap:18px}.feature-article,.mini-article,.info-panel,.paper-card,.topic-note{background:white;border:1px solid var(--line);border-radius:13px;padding:25px;min-width:0}.feature-article{border-top:4px solid var(--cyan)}.feature-article h3{font-size:25px}.feature-article p,.mini-article p{color:var(--muted)}.mini-stack{display:grid;gap:18px}.article-link{font-size:14px;font-weight:700}.split-section{display:grid;grid-template-columns:1fr 1fr;align-items:center;gap:35px;min-width:0}.split-section>*,.card-pair>*{min-width:0}.split-section.reversed .media{order:-1}.small-heading{font-size:13px;color:#168A9D;font-weight:800;margin:0 0 7px}.chipline{display:flex;gap:8px;flex-wrap:wrap;margin:14px 0}.chipline span{font-size:12px;border:1px solid #B8D9E4;border-radius:5px;padding:2px 9px;color:var(--deep)}.rule-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:15px}.rule-block{padding:24px;background:var(--surface);border-radius:12px;border-left:3px solid var(--cyan)}.rule-block b{display:block;color:var(--deep);font-size:18px}.rule-block p{font-size:14px;color:var(--muted)}.steps-row{display:grid;grid-template-columns:repeat(4,1fr);gap:14px;counter-reset:step}.steps-row>div{padding:17px;border-top:2px solid var(--cyan);background:#fff;border-radius:0 0 9px 9px}.steps-row b{color:var(--deep)}.steps-row p{font-size:14px;margin-bottom:0}.editor-note{padding:16px 20px;border-left:3px solid var(--blue);background:var(--pale2);font-size:14px;margin-top:26px}.page-header{padding:46px 0 25px}.page-header .lead{max-width:810px;font-size:17px;color:#4C687E;margin:12px 0 0}.page-header h1{font-size:clamp(30px,2.8vw,36px)}.breadcrumb{font-size:13px;color:var(--muted);margin-bottom:18px}.breadcrumb a{color:var(--muted)}.page-content{padding:10px 0 65px}.body-section{margin:30px 0 40px}.body-section h2{padding-bottom:12px;border-bottom:1px solid var(--line);margin-bottom:19px}.article-narrow{max-width:780px}.prose{max-width:780px}.prose p{font-size:16.5px;line-height:1.85}.table-scroll{width:100%;overflow-x:auto;border:1px solid var(--line);border-radius:11px;background:#fff;margin:19px 0}table{width:100%;border-collapse:collapse;min-width:530px;font-size:14px}th,td{border-bottom:1px solid var(--line);padding:14px 16px;vertical-align:top;text-align:left}th{color:var(--deep);font-weight:800;background:#EAF6FA}tr:last-child td{border-bottom:0}.compare-layout{display:grid;grid-template-columns:minmax(0,1.4fr) minmax(280px,1fr);gap:24px;align-items:center}.timeline{display:grid;grid-template-columns:repeat(3,1fr);gap:16px}.timeline article{border-top:3px solid var(--cyan);padding:20px;background:#fff;border-radius:0 0 10px 10px}.timeline .index{color:#0794A7;font-size:12px;font-weight:800;letter-spacing:.08em}.timeline h3{margin:7px 0}.timeline p{font-size:14px}.article-with-aside{display:grid;grid-template-columns:minmax(0,760px) minmax(210px,240px);gap:40px;align-items:start}.aside-panel{position:sticky;top:24px;background:var(--pale2);padding:23px;border-radius:11px}.aside-panel h2{font-size:18px}.aside-panel dt{color:var(--deep);font-weight:800}.aside-panel dd{margin:0 0 17px;font-size:13px}.numbered-flow{counter-reset:flow;list-style:none;padding:0;display:grid;gap:13px}.numbered-flow li{padding:19px 20px 19px 65px;background:#fff;border:1px solid var(--line);border-radius:10px;position:relative}.numbered-flow li:before{counter-increment:flow;content:counter(flow,decimal-leading-zero);position:absolute;left:18px;top:18px;color:#0795A6;font-weight:800}.numbered-flow strong{color:var(--deep)}.matrix{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:16px}.matrix article{background:#fff;border:1px solid var(--line);border-radius:12px;padding:24px}.matrix h3{font-size:20px}.matrix ul{padding-left:18px;font-size:14px}.quote-strip{border-left:4px solid var(--cyan);background:#eaf6fa;padding:24px 28px;color:var(--deep);font-size:19px;line-height:1.7}.gallery{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:20px}.gallery article{background:#fff;border:1px solid var(--line);padding:17px;border-radius:13px}.gallery h3{font-size:18px;margin:16px 4px 6px}.gallery p{margin:0 4px 6px;color:var(--muted);font-size:14px}.anchor-nav{display:flex;flex-wrap:wrap;gap:8px;margin:22px 0}.anchor-nav a{padding:8px 12px;text-decoration:none;border-radius:6px;background:#e4f2f7;font-size:14px;font-weight:700}.faq details{background:#fff;border:1px solid var(--line);border-radius:9px;padding:14px 18px;margin-bottom:10px}.faq summary{cursor:pointer;color:var(--deep);font-weight:700}.faq details p{margin:10px 0 0;font-size:14.5px}.related{background:var(--pale2);border-radius:13px;padding:25px;margin-top:50px}.related h2{font-size:21px}.related-links{display:grid;grid-template-columns:repeat(3,1fr);gap:11px}.related-links a{background:#fff;padding:13px 15px;border:1px solid var(--line);border-radius:7px;font-size:14px;text-decoration:none;font-weight:700}.note{font-size:13px;color:var(--muted)}.site-footer{background:var(--footer);color:#EAF7FF}.footer-grid{display:grid;grid-template-columns:1.2fr 1fr 1.2fr;gap:55px;padding-top:52px;padding-bottom:35px}.footer-grid h2{font-size:17px;color:#fff}.footer-grid p{font-size:13px;color:#D0E5F0}.footer-brand{font-size:21px;color:#fff;display:block}.footer-grid nav{display:grid;grid-template-columns:1fr 1fr;gap:5px 17px}.footer-grid a{color:#EAF7FF;font-size:13px}.footer-about{display:inline-block;margin-top:10px}.footer-bottom{border-top:1px solid #ffffff30;padding-top:16px;padding-bottom:21px;display:flex;justify-content:space-between;font-size:12px}.footer-bottom a{color:#EAF7FF}.mobile-bottom{display:none}.back-top{position:fixed;right:22px;bottom:23px;z-index:12;width:42px;height:42px;border:0;border-radius:9px;background:var(--deep);color:#fff;font-size:24px;opacity:0;pointer-events:none;transition:opacity .2s}.back-top.is-visible{opacity:1;pointer-events:auto}
@media(max-width:980px){.topbar{height:63px;justify-content:space-between;gap:9px}.topbar-caption,.desktop-navigation{display:none}.menu-toggle{display:flex}.brand{margin-right:auto}.brand img{max-height:30px;max-width:180px}.brand-type{font-size:19px}.entry-button{padding:9px 13px;font-size:13px}.quicklinks .wrap{flex-wrap:wrap;justify-content:flex-start;gap:7px 22px}.topic-grid{grid-template-columns:repeat(3,minmax(0,1fr))}.footer-grid{gap:25px}}
@media(max-width:760px){.wrap{width:calc(100% - 44px)}.hero-grid,.split-section,.editorial-grid,.compare-layout,.article-with-aside{grid-template-columns:1fr}.home-hero{padding:30px 0}.hero-grid{gap:20px}.hero-grid .hero-copy{order:1}.hero-grid .media{order:2}.split-section.reversed .media{order:0}.section{padding:37px 0}.timeline,.matrix{grid-template-columns:1fr 1fr}.aside-panel{position:static}.footer-grid{grid-template-columns:1fr 1fr}.footer-grid>div:first-child{grid-column:1/-1}.gallery{gap:13px}.related-links{grid-template-columns:1fr}.steps-row{grid-template-columns:1fr 1fr}}
@media(max-width:640px){body{font-size:15px}.wrap{width:calc(100% - 32px)}h1{font-size:29px}.page-header{padding:32px 0 15px}.page-header h1{font-size:27px}.page-header .lead{font-size:15px}.hero-copy h1{font-size:30px}.topic-grid,.matrix,.gallery,.timeline,.rule-grid{grid-template-columns:1fr}.topic-card{padding:17px}.section-heading h2{font-size:22px}.media--hero{height:200px}.media--feature{height:180px}.media--card{height:145px}.media--banner{height:150px}.media--mobile{height:290px;max-width:250px}.media-placeholder{width:70%}.feature-article,.mini-article,.info-panel,.paper-card,.topic-note{padding:19px}.feature-article h3{font-size:21px}.body-section h2{font-size:22px}.steps-row{grid-template-columns:1fr 1fr}.footer-grid{grid-template-columns:1fr;gap:16px;padding-top:32px}.footer-grid>div:first-child{grid-column:auto}.footer-bottom{gap:10px;flex-wrap:wrap;padding-bottom:20px}.mobile-bottom{display:grid;grid-template-columns:repeat(4,1fr);position:fixed;bottom:0;left:0;right:0;z-index:19;background:#fff;border-top:1px solid var(--line);padding-bottom:env(safe-area-inset-bottom);box-shadow:0 -5px 24px #12365312}.mobile-bottom a{text-align:center;text-decoration:none;color:var(--deep);font-weight:700;font-size:12px;padding:10px 5px;min-height:44px}.mobile-bottom a[aria-current=page]{color:#087D9B;border-top:3px solid var(--cyan)}body{padding-bottom:calc(44px + env(safe-area-inset-bottom))}.back-top{right:12px;bottom:calc(60px + env(safe-area-inset-bottom))}.topbar .brand img{max-width:145px}.brand-type{font-size:17px}.brand-type small{font-size:8px}.quicklinks .wrap{padding-top:9px;padding-bottom:9px}.quick-group{font-size:12px}.related{padding:18px}}
@media(max-height:430px) and (max-width:640px){.mobile-bottom{position:static}.back-top{bottom:12px}body{padding-bottom:0}}
@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}*,*:before,*:after{transition:none!important;animation:none!important}}
