:root{--bg:#F6FAFC;--white:#fff;--pale:#EAF6FA;--pale2:#EDF4F8;--cyan:#25C8D1;--sky:#25B6E8;--blue:#1787DB;--navy:#174B78;--title:#183A56;--text:#31485D;--muted:#687D8E;--border:#DCE9F0;--footer:#123653;--radius:17px}
*{box-sizing:border-box}html{scroll-behavior:smooth;scroll-padding-top:26px}body{margin:0;background:var(--bg);color:var(--text);font:16px/1.82 Arial,"PingFang SC","Microsoft YaHei",sans-serif;overflow-wrap:break-word}body.drawer-active{overflow:hidden}img{max-width:100%}a{color:var(--navy);text-decoration-thickness:1px;text-underline-offset:4px}a:hover{color:#126cae}a:focus-visible,button:focus-visible,summary:focus-visible{outline:3px solid var(--sky);outline-offset:3px}button{font:inherit;cursor:pointer}h1,h2,h3{color:var(--title);line-height:1.36;margin:0 0 .7em;font-weight:750}h1{font-size:clamp(27px,3.3vw,42px);letter-spacing:-.025em}h2{font-size:clamp(20px,2.3vw,27px)}h3{font-size:clamp(17px,1.6vw,21px)}p{margin:0 0 1.1em}ul,ol{padding-left:1.4em;margin-top:.3em}li+li{margin-top:.45em}.container{width:min(1180px,calc(100% - 56px));margin-inline:auto}.content-wrap{padding-top:44px;padding-bottom:60px}.section{margin-top:60px}.section-heading{margin-bottom:23px}.section-heading p{max-width:760px;color:var(--muted)}.eyebrow{display:inline-block;color:#117e9d;font-size:13px;letter-spacing:.1em;font-weight:700;margin-bottom:11px;text-transform:uppercase}.lead{font-size:17px;color:#486076;max-width:780px}.small{font-size:14px;color:var(--muted)}.muted{color:var(--muted)}.skip-link{position:absolute;z-index:100;top:-70px;left:12px;background:#fff;padding:8px 14px}.skip-link:focus{top:8px}.site-header{background:#fff;border-bottom:1px solid var(--border)}.header-main{height:72px;display:flex;align-items:center;gap:26px}.brand{display:inline-flex;align-items:center;text-decoration:none;min-width:0}.header-tagline{color:var(--muted);font-size:14px;letter-spacing:.04em;margin-left:auto}.entry-button{display:inline-flex;align-items:center;justify-content:center;gap:10px;padding:8px 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span{height:2px;width:100%;background:var(--navy);display:block}.mobile-drawer,.drawer-overlay,.bottom-nav{display:none}.media{display:flex;align-items:center;justify-content:center;width:100%;min-width: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{display:block;width:72%;height:55%;border:1px solid #d4e6ee;border-radius:12px;background:linear-gradient(135deg,#eff9fc,#e4f0f5)}.media--logo{width:auto;max-width:270px;height:38px;border-radius:0;background:transparent;justify-content:flex-start;overflow:visible}.media--logo img{max-height:38px}.media--logo .media-placeholder{width:155px;height:30px;border-radius:4px;background:#e7f1f5}.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}.hero{display:grid;grid-template-columns:56fr 44fr;gap:28px;align-items:center;padding:54px 0 30px}.hero-text{padding-right:16px}.hero-text p{max-width:600px}.actions{display:flex;gap:11px;flex-wrap:wrap;margin-top:21px}.button{display:inline-flex;align-items:center;padding:11px 19px;min-height:44px;text-decoration:none;border-radius:8px;font-weight:700;line-height:1.4}.button-primary{background:linear-gradient(100deg,#168bc9,#1787db);color:white}.button-primary:hover{background:#156caa;color:white}.button-secondary{background:#e5f3fa;border:1px solid #d0e4ef}.quickbar{background:#fff;border-block:1px solid var(--border);padding:16px 0}.quickbar-inner{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:16px}.quickbar-group{display:flex;gap:9px;align-items:center;flex-wrap:wrap;font-size:13px}.quickbar-group strong{color:var(--title)}.quickbar-group a{white-space:nowrap}.topic-grid{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:14px}.topic-card{background:#fff;border:1px solid var(--border);border-radius:var(--radius);padding:22px;text-decoration:none;display:flex;flex-direction:column;gap:7px}.topic-card:hover{border-color:#8ad8e2;box-shadow:0 7px 21px rgba(23,75,120,.06)}.topic-card strong{font-size:18px;color:var(--title)}.topic-card span{font-size:14px;color:var(--muted);line-height:1.7}.topic-card em{font-style:normal;margin-top:auto;color:#1787db;font-size:13px}.feature-split{display:grid;grid-template-columns:2fr 1fr;gap:18px}.feature-primary,.feature-side,.essay-card,.info-panel,.light-panel,.quote-panel{border-radius:var(--radius);padding:26px;background:#fff;border:1px solid var(--border)}.feature-primary{background:var(--pale)}.feature-primary h3{font-size:24px}.feature-side + .feature-side{margin-top:18px}.feature-side h3{font-size:19px}.feature-sides{min-width:0}.two-col{display:grid;grid-template-columns:1fr 1fr;gap:28px;align-items:center}.two-col--reverse .media{order:-1}.accent-section{background:#eaf6fa;border-top:1px solid #dcebf1;border-bottom:1px solid #dcebf1;padding:56px 0;margin-top:60px}.triple-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:17px}.essay-card .symbol{font-size:27px;color:#0b91af;line-height:1;margin-bottom:14px}.essay-card h3{margin-bottom:8px}.steps{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:16px;counter-reset:step}.step{position:relative;padding:20px;border-top:3px solid var(--cyan);background:#fff;border-radius:0 0 12px 12px}.step .step-number{display:block;font-size:14px;color:#168b9c;font-weight:800;margin-bottom:10px}.step h3{font-size:18px}.editor-note{padding:20px 24px;border-left:4px solid var(--cyan);background:#fff;margin-top:38px}.page-top{padding:0 0 24px;border-bottom:1px solid var(--border);margin-bottom:35px}.page-top .lead{margin-bottom:0}.article-text{max-width:780px}.article-text p{margin-bottom:1.15em}.article-section{margin:37px 0}.article-section h2{margin-bottom:14px}.article-section h3{margin-top:23px}.section-inline{margin-top:33px}.data-table-wrap{width:100%;overflow-x:auto;border:1px solid var(--border);border-radius:12px;background:#fff;margin:20px 0}.data-table{border-collapse:collapse;width:100%;min-width:540px;font-size:15px}.data-table th,.data-table td{padding:13px 17px;text-align:left;border-bottom:1px solid var(--border);vertical-align:top}.data-table th{color:var(--title);background:#eaf6fa;font-weight:750}.data-table tr:last-child td{border-bottom:0}.numbered{counter-reset:item;list-style:none;padding:0;display:grid;gap:13px}.numbered li{counter-increment:item;display:grid;grid-template-columns:42px 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#38607b;padding-top:14px;font-size:13px;color:#b7d6e6;margin-top:28px}.back-top{position:fixed;bottom:25px;right:22px;z-index:9;background:var(--navy);color:#fff;border:0;border-radius:50%;width:44px;height:44px;opacity:0;visibility:hidden;pointer-events:none;transition:opacity .2s}.back-top.is-visible{opacity:1;visibility:visible;pointer-events:auto}
@media(max-width:1100px){.topic-grid{grid-template-columns:repeat(3,minmax(0,1fr))}.reading-layout{grid-template-columns:minmax(0,1fr) 220px;gap:27px}}
@media(max-width:980px){.container{width:calc(100% - 44px)}.header-main{height:62px;justify-content:space-between;gap:12px}.menu-button{display:flex;flex:0 0 auto}.header-tagline,.desktop-nav{display:none}.brand{margin:0 auto}.media--logo{height:30px;max-width:190px}.media--logo img{max-height:30px}.entry-button{min-height:40px;padding:7px 13px;font-size:13px}.drawer-overlay{display:block;position:fixed;inset:0;background:rgba(9,31,47,.52);z-index:49;opacity:0;visibility:hidden;pointer-events:none;transition:opacity .2s,visibility .2s}.mobile-drawer{display:block;position:fixed;z-index:50;top:0;left:0;bottom:0;width:min(86vw,344px);background:#fff;overflow-y:auto;box-shadow:8px 0 30px rgba(6,35,54,.15);transform:translateX(-105%);visibility:hidden;pointer-events:none;transition:transform .22s,visibility .22s;padding:20px 22px}.drawer-active .drawer-overlay{opacity:1;visibility:visible;pointer-events:auto}.drawer-active .mobile-drawer{transform:translateX(0);visibility:visible;pointer-events:auto}.drawer-head{display:flex;justify-content:space-between;align-items:center;border-bottom:1px solid var(--border);padding-bottom:12px}.drawer-head strong{color:var(--title)}.drawer-head button{border:0;background:var(--pale);width:40px;height:40px;font-size:25px;border-radius:8px;color:var(--title)}.drawer-group{margin-top:20px}.drawer-group h2{font-size:13px;color:var(--muted);letter-spacing:.06em}.drawer-group a{display:block;text-decoration:none;padding:9px 10px;color:var(--title);border-radius:7px}.drawer-group a[aria-current="page"]{background:var(--pale);font-weight:700}.quickbar-inner{grid-template-columns:1fr;gap:8px}.topic-grid{grid-template-columns:repeat(2,minmax(0,1fr))}.reading-layout{grid-template-columns:minmax(0,1fr)}.side-glossary{max-width:780px}}
@media(max-width:760px){.hero{grid-template-columns:1fr;padding-top:32px;gap:18px}.hero-text{padding:0}.hero .media{order:-1}.feature-split,.two-col,.footer-layout{grid-template-columns:1fr}.two-col .media,.two-col--reverse .media{order:-1}.feature-primary,.feature-side,.essay-card,.info-panel,.light-panel{padding:20px}.triple-grid,.matrix{grid-template-columns:1fr}.steps{grid-template-columns:repeat(2,minmax(0,1fr))}.related-grid{grid-template-columns:1fr}.gallery-grid{grid-template-columns:1fr}.section,.accent-section{margin-top:40px}.accent-section{padding:38px 0}.content-wrap{padding-top:30px}.bottom-nav{display:grid;position:fixed;z-index:15;bottom:0;left:0;right:0;grid-template-columns:repeat(4,1fr);min-height:58px;padding-bottom:env(safe-area-inset-bottom);background:#fff;border-top:1px solid var(--border)}.bottom-nav a{display:flex;align-items:center;justify-content:center;text-decoration:none;color:var(--title);font-size:13px;font-weight:700;min-height:56px}.site-footer{padding-bottom:calc(80px + env(safe-area-inset-bottom))}.back-top{bottom:calc(82px + env(safe-area-inset-bottom))}.media--hero{height:210px}.media--feature{height:185px}.media--card{height:145px}.media--banner{height:150px}.media--mobile{height:290px;max-width:250px}}
@media(max-width:640px){.container{width:calc(100% - 32px)}body{font-size:15px;line-height:1.79}.lead{font-size:15.5px}.topic-grid{gap:10px}.topic-card{padding:16px}.topic-card strong{font-size:16px}.topic-card span{font-size:13px}.steps{grid-template-columns:1fr}.footer-bottom{flex-direction:column;gap:6px}.site-footer{padding-top:32px}.footer-links{font-size:14px}.media--hero{height:200px}.entry-button{padding-inline:10px}.header-main{gap:8px}.brand{max-width:40vw}.gallery-item{padding:12px}}
@media(max-height:540px) and (max-width:760px){.bottom-nav{position:static;padding-bottom:0}.site-footer{padding-bottom:25px}.back-top{bottom:20px}}
@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}*,*::before,*::after{transition:none!important;animation:none!important}}