:root{--bg:#F6FAFC;--white:#fff;--pale:#EAF6FA;--pale2:#EDF4F8;--cyan:#25C8D1;--sky:#25B6E8;--blue:#1787DB;--deep:#174B78;--title:#183A56;--ink:#31485D;--muted:#687D8E;--line:#DCE9F0;--footer:#123653;--max:1180px}*{box-sizing:border-box}html{scroll-behavior:smooth;scroll-padding-top:32px}body{margin:0;background:var(--bg);color:var(--ink);font:16px/1.8 Arial,'PingFang SC','Microsoft YaHei',sans-serif;overflow-x:hidden}img{display:block;max-width:100%}a{color:var(--deep);text-decoration-thickness:1px;text-underline-offset:4px}a:hover{color:var(--blue)}a:focus-visible,button:focus-visible,summary:focus-visible{outline:3px solid var(--sky);outline-offset:3px}button{font:inherit;cursor:pointer}.wrap{width:min(var(--max),calc(100% - 56px));margin-inline:auto}.skip-link{position:absolute;left:12px;top:-70px;background:white;padding:8px;z-index:300}.skip-link:focus{top:10px}.site-header{background:#fff;border-bottom:1px solid 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var(--line);border-radius:12px;padding:21px;text-decoration:none;min-height:170px;transition:transform .2s,border-color .2s}.topic-card:hover{transform:translateY(-3px);border-color:var(--sky)}.topic-card strong{display:block;font-size:17px;line-height:1.4;color:var(--title);margin-bottom:8px}.topic-card p{font-size:14px;color:var(--muted);margin:0}.topic-card .arrow{color:var(--blue);font-weight:700}.editor-grid{display:grid;grid-template-columns:1.85fr 1fr;gap:16px}.editor-feature,.editor-aside article,.paper,.info-card{background:white;border:1px solid var(--line);border-radius:13px;padding:26px}.editor-feature{background:var(--pale)}.editor-feature h3{font-size:25px;line-height:1.42;margin:12px 0;color:var(--title)}.editor-aside{display:grid;gap:16px}.editor-aside h3,.paper h3,.info-card h3{color:var(--title);line-height:1.45;margin:0 0 12px;font-size:19px}.editor-aside p,.editor-feature p{margin:0 0 14px}.feature-split{display:grid;grid-template-columns:1fr 1fr;gap:36px;align-items:center}.feature-split.reverse .media{order:0}.feature-split.reverse .feature-copy{order:1}.feature-copy h2{font-size:27px;color:var(--title);line-height:1.4}.feature-copy p{margin:0 0 16px}.text-link{font-weight:700}.mini-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:16px}.info-card{position:relative}.info-card .num{font-size:13px;color:#087F9D;font-weight:700}.reading-path{counter-reset:step;display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:16px}.reading-path div{padding:19px 15px;border-top:3px solid var(--cyan);background:white}.reading-path strong{color:var(--title);display:block}.notice{padding:23px 26px;background:var(--pale);border-left:4px solid var(--cyan);border-radius:6px}.page-intro{padding-top:48px;padding-bottom:30px}.page-intro h1{font-size:clamp(25px,3vw,36px);color:var(--title);line-height:1.42;margin:10px 0 14px}.page-intro .lead{max-width:840px;margin:0}.prose{max-width:780px}.prose h2,.content-section h2{color:var(--title);font-size:25px;line-height:1.42;margin:0 0 17px}.prose h3,.content-section h3{color:var(--title);font-size:19px;line-height:1.45}.prose p,.content-section p{margin:0 0 17px}.content-section{margin-block:44px}.content-section:target{scroll-margin-top:24px}.table-scroll{overflow-x:auto;background:white;border:1px solid var(--line);border-radius:10px;margin:18px 0 26px}.data-table{width:100%;border-collapse:collapse;min-width:620px;text-align:left}.data-table th,.data-table td{padding:13px 17px;border-bottom:1px solid var(--line);vertical-align:top}.data-table th{background:var(--pale);color:var(--title)}.data-table tr:last-child td{border-bottom:0}.steps{list-style:none;counter-reset:steps;display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:15px;padding:0}.steps li{background:white;border:1px solid var(--line);border-radius:10px;padding:22px}.steps li::before{counter-increment:steps;content:'0' 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var(--line);background:#fff;border-radius:6px;text-decoration:none;padding:6px 13px}.faq details{background:white;border:1px solid var(--line);border-radius:8px;margin-bottom:9px;padding:13px 20px}.faq summary{cursor:pointer;font-weight:700;color:var(--title)}.faq details p{margin:11px 0 0}.related{background:var(--pale2);padding:26px;border-radius:12px;margin-block:50px}.related-links{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:12px}.related-links a{padding:12px 14px;background:white;border-radius:7px;font-weight:700;text-decoration:none}.related-links span{float:right}.media{display:flex;justify-content:center;align-items:center;min-width:0;width:100%;overflow:hidden;border-radius:14px;background:var(--pale);border:1px solid var(--line)}.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}.media--empty{background:linear-gradient(135deg,#EAF6FA,#F7FAFC)}.site-footer{background:var(--footer);color:#EAF7FF;padding:48px 0 20px;margin-top:62px}.footer-grid{display:grid;grid-template-columns:1.2fr 1fr;gap:60px}.footer-brand{font-size:21px}.footer-brand span{font-size:10px;letter-spacing:.15em;margin-left:9px}.footer-note{max-width:620px;color:#C8DFEC;font-size:13px}.footer-links{display:flex;flex-wrap:wrap;gap:7px 20px;margin-top:12px}.site-footer a{color:#EAF7FF}.footer-bottom{border-top:1px solid #ffffff24;margin-top:29px;padding-top:17px;display:flex;justify-content:space-between;gap:12px;font-size:12px;color:#C8DFEC}.back-top{position:fixed;right:22px;bottom:22px;border:0;background:var(--deep);color:#fff;border-radius:50%;width:44px;height:44px;opacity:0;pointer-events:none;transition:opacity .2s;z-index:15}.back-top.visible{opacity:1;pointer-events:auto}.muted{color:var(--muted)}.pullquote{border-left:3px solid var(--cyan);background:var(--pale);padding:18px 22px;margin:25px 0;font-size:18px;color:var(--title)}.service-table{min-width:540px}
@media(max-width:980px){.wrap{width:calc(100% - 44px)}.header-bar{height:62px;justify-content:space-between}.menu-toggle{display:flex;flex:0 0 40px;width:40px;height:40px;border:1px solid var(--line);background:white;border-radius:8px;flex-direction:column;align-items:center;justify-content:center;gap:5px}.menu-toggle span{width:17px;height:2px;background:var(--deep)}.brand{margin-inline:auto}.brand img{max-height:30px;max-width:180px}.header-tagline,.desktop-nav{display:none}.header-cta{height:40px;min-height:40px;padding:7px 12px;font-size:13px}.drawer-backdrop{display:block;position:fixed;inset:0;background:#061E35a8;z-index:90;visibility:hidden;opacity:0;pointer-events:none;transition:opacity .2s,visibility .2s}.mobile-drawer{display:block;position:fixed;left:0;top:0;bottom:0;width:min(86vw,344px);background:white;z-index:91;overflow-y:auto;transform:translateX(-101%);visibility:hidden;pointer-events:none;transition:transform .25s,visibility .25s;padding:20px 22px}.drawer-open .drawer-backdrop{visibility:visible;opacity:1;pointer-events:auto}.drawer-open .mobile-drawer{transform:translateX(0);visibility:visible;pointer-events:auto}.drawer-top{display:flex;align-items:center;justify-content:space-between;color:var(--title)}.drawer-close{background:var(--pale);border:0;font-size:28px;width:40px;height:40px}.drawer-label{font-size:12px;letter-spacing:.1em;color:var(--muted);margin:22px 0 6px}.mobile-drawer>a{display:block;border-bottom:1px solid var(--line);padding:10px 1px;text-decoration:none;font-weight:700}.topic-grid{grid-template-columns:repeat(2,minmax(0,1fr))}.body-grid{grid-template-columns:minmax(0,1fr) 220px;gap:22px}.quick-grid{gap:8px}}
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@media(max-width:640px){body{font-size:15px;line-height:1.78}.wrap{width:calc(100% - 32px)}.brand img{max-width:125px;max-height:29px}.brand-word{font-size:16px}.brand-word small{font-size:8px}.header-bar{gap:7px}.header-cta{padding:6px 10px;font-size:12px}.header-cta span{display:none}.hero h1{font-size:29px}.lead{font-size:15px}.section{margin-block:36px}.section-head h2,.section h2{font-size:22px}.topic-grid,.gallery,.editor-aside{grid-template-columns:1fr}.topic-card{min-height:0;padding:17px}.editor-feature,.editor-aside article,.paper,.info-card{padding:19px}.feature-copy h2{font-size:22px}.page-intro{padding-top:33px;padding-bottom:14px}.page-intro h1{font-size:26px}.prose h2,.content-section h2{font-size:22px}.content-section{margin-block:32px}.media--hero{height:200px}.media--feature{height:180px}.media--card{height:145px}.media--banner{height:150px}.media--mobile{height:290px;max-width:250px}.reading-path{gap:8px}.reading-path div{padding:12px}.site-footer{padding-bottom:95px}.footer-bottom{flex-direction:column}.mobile-bottom{display:grid;grid-template-columns:repeat(4,1fr);position:fixed;bottom:0;left:0;right:0;background:#fff;border-top:1px solid var(--line);z-index:38;padding-bottom:env(safe-area-inset-bottom);box-shadow:0 -2px 14px #102c4012}.mobile-bottom a{text-align:center;text-decoration:none;padding:10px 2px;min-height:44px;font-size:13px;font-weight:700}.mobile-bottom a[aria-current]{color:var(--blue);box-shadow:inset 0 3px var(--cyan)}.back-top{bottom:70px;right:15px}.gallery figure{padding:10px}.related{padding:20px}.quick-strip{margin-top:30px}}
@media(max-height:480px) and (max-width:640px){.mobile-bottom{position:static}.site-footer{padding-bottom:20px}.back-top{bottom:16px}}@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}*,*::before,*::after{transition:none!important;animation:none!important}}@media(min-width:981px){.mobile-drawer{display:none!important}.drawer-backdrop{display:none!important}}

.nojs-nav{display:flex;flex-wrap:wrap;gap:8px 18px;padding-block:12px}.nojs-nav a{font-weight:700;font-size:13px}