:root{--bg:#F6FAFC;--surface:#fff;--pale:#EAF6FA;--pale2:#EDF4F8;--aqua:#25C8D1;--sky:#25B6E8;--blue:#1787DB;--navy:#174B78;--title:#183A56;--body:#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(--bg);font-family:Arial,"PingFang SC","Microsoft YaHei",sans-serif;color:var(--body);line-height:1.8;font-size:16px;overflow-x:hidden}a{color:var(--navy);text-decoration:none}a:hover{text-decoration:underline;text-underline-offset:4px}a:focus-visible,button:focus-visible,summary:focus-visible{outline:3px solid var(--sky);outline-offset:4px}button{font:inherit;cursor:pointer}img{max-width:100%}.shell{max-width:1180px;margin-inline:auto;padding-inline:28px}.skip-link{position:absolute;left:10px;top:-80px;z-index:100;padding:8px 12px;background:#fff}.skip-link:focus{top:10px}.site-header{background:#fff;border-bottom:1px solid var(--line);position:relative;z-index:20}.topbar{height:72px;display:flex;align-items:center;gap:22px}.brand{display:inline-flex;align-items:center;flex-shrink:0;min-width:150px}.brand .media{background:transparent;border:0;border-radius:0;justify-content:flex-start}.media--logo{height:38px}.media--logo img{max-height:38px}.wordmark{display:inline-flex;flex-direction:column;font-weight:800;line-height:1.1;font-size:24px;color:var(--navy);letter-spacing:.04em}.wordmark>span{color:var(--blue)}.wordmark small{font-weight:600;font-size:9px;letter-spacing:.18em;margin-top:4px;color:var(--muted)}.brand-note{font-size:14px;color:var(--muted);margin-left:auto}.entry-button{display:inline-flex;align-items:center;justify-content:center;padding:8px 24px;min-height:42px;border-radius:8px;color:#fff;background:var(--navy);font-weight:700;white-space:nowrap}.entry-button:hover{background:#226394;color:#fff;text-decoration:none}.desktop-nav{background:var(--navy)}.nav-track{min-height:48px;display:flex;align-items:stretch;justify-content:space-between;gap:10px}.nav-track a{color:#e8f6ff;position:relative;padding:10px 8px;font-size:15px;white-space:nowrap}.nav-track a[aria-current=page]{font-weight:700;color:white}.nav-track a[aria-current=page]:after{content:"";position:absolute;bottom:0;left:8px;right:8px;background:var(--aqua);height:3px}.nav-track a:hover{color:#fff}.menu-button,.drawer-close,.drawer-overlay{display:none}.mobile-drawer{display:none}.bottom-nav{display:none}main{min-height:65vh}.page-section{padding-block:56px}.section-soft{background:var(--pale2)}.section-white{background:#fff}.eyebrow{display:block;font-size:12px;letter-spacing:.14em;font-weight:800;text-transform:uppercase;color:#087d9e;margin-bottom:12px}.hero{display:grid;grid-template-columns:minmax(0,1.12fr) minmax(0,.88fr);gap:44px;align-items:center;padding-top:48px;padding-bottom:56px}.hero h1{font-size:clamp(30px,3.6vw,42px);line-height:1.35;margin:0 0 18px;color:var(--title)}h1,h2,h3{color:var(--title);line-height:1.4}h1{font-size:34px}h2{font-size:26px;margin:0 0 22px}h3{font-size:20px;margin:0 0 12px}p{margin:0 0 17px}.lead{font-size:17px;line-height:1.82}.hero .media{border-radius:18px}.media{display:flex;align-items:center;justify-content:center;width:100%;min-width:0;overflow:hidden;background:var(--pale);border:1px solid var(--line);border-radius:14px;margin:0}.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}.btn-row{display:flex;flex-wrap:wrap;gap:12px;margin-top:26px}.btn-primary,.btn-outline{padding:10px 18px;border-radius:8px;font-weight:700;display:inline-block}.btn-primary{background:var(--navy);color:white}.btn-primary:hover{background:var(--blue);text-decoration:none;color:white}.btn-outline{border:1px solid #a9c5d7}.btn-outline:hover{background:var(--pale);text-decoration:none}.quick-strip{border-block:1px solid var(--line);background:#fff}.quick-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:18px;padding-block:17px}.quick-grid div{font-size:14px;line-height:1.6}.quick-grid strong{display:block;font-size:13px;color:var(--muted);margin-bottom:5px}.quick-grid a{margin-right:12px;white-space:nowrap}.section-head{max-width:750px;margin-bottom:24px}.section-head p{color:var(--muted)}.topic-grid{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:14px}.topic{display:block;border:1px solid var(--line);background:#fff;padding:22px;border-radius:12px;transition:border-color .2s,transform .2s;min-width:0}.topic:hover{border-color:#60bbcf;text-decoration:none;transform:translateY(-2px)}.topic strong{display:block;color:var(--title);font-size:18px;margin-bottom:10px}.topic span{font-size:14px;color:var(--body);line-height:1.7;display:block}.editor-grid{display:grid;grid-template-columns:2fr 1fr;gap:18px}.panel{border:1px solid var(--line);background:#fff;padding:25px;border-radius:14px}.panel-accent{background:var(--pale)}.panel p:last-child{margin-bottom:0}.stack{display:grid;gap:18px}.split{display:grid;grid-template-columns:minmax(0,1fr) 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var(--line)}.content-section h2{margin-bottom:17px}.content-section p{max-width:780px}.content-section ul,.content-section ol{padding-left:25px;margin:0 0 20px}.content-section li{margin-bottom:9px}.feature-band{background:var(--pale2);padding:24px;border-radius:14px;margin-block:22px}.data-table{overflow-x:auto;max-width:100%;border:1px solid var(--line);border-radius:10px;margin:18px 0 25px}.data-table table{width:100%;border-collapse:collapse;min-width:550px;background:#fff;font-size:15px}.data-table th{text-align:left;background:#eaf6fa;color:var(--title);font-weight:700}.data-table th,.data-table td{border-bottom:1px solid var(--line);padding:12px 16px;vertical-align:top}.data-table tr:last-child td{border-bottom:none}.guide-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:14px}.guide-card{background:#fff;border:1px solid var(--line);padding:20px;border-radius:12px}.guide-card h3{margin:0 0 10px}.guide-card p{font-size:15px}.article-layout{display:grid;grid-template-columns:minmax(0,760px) minmax(0,240px);gap:48px;align-items:start}.article-layout article{min-width:0}.article-side{position:sticky;top:20px;padding:21px;background:var(--pale);border-radius:12px;font-size:14px}.article-side h2{font-size:19px}.article-side dt{font-weight:700;color:var(--title)}.article-side dd{margin:0 0 14px}.number-list{list-style:none;counter-reset:read;padding:0!important}.number-list li{counter-increment:read;padding:17px 20px 17px 55px;background:#fff;border:1px solid var(--line);border-radius:10px;position:relative}.number-list li:before{content:counter(read);position:absolute;left:19px;top:15px;font-size:22px;font-weight:800;color:var(--blue)}.related{background:var(--pale);border-radius:14px;padding:24px;margin-block:35px}.related h2{font-size:21px;margin-bottom:12px}.related ul{display:flex;flex-wrap:wrap;gap:14px 28px;padding:0;list-style:none;margin:0}.related 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p{color:#d7e9f2}.footer-grid{display:grid;grid-template-columns:2fr 1fr;gap:70px}.footer-brand{font-size:22px;font-weight:800}.footer-brand small{font-size:12px;letter-spacing:.12em;display:block}.site-footer h2{font-size:17px;color:white;margin:0 0 13px}.site-footer nav{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:6px 12px}.site-footer a{color:#eaf7ff}.site-footer .fine{color:#b6cfde;max-width:680px}.footer-bottom{display:flex;justify-content:space-between;align-items:center;gap:16px;border-top:1px solid #40657e;margin-top:32px;padding-top:16px;font-size:13px;color:#c7dce7}.back-top{position:fixed;bottom:26px;right:20px;border:0;background:var(--navy);color:white;border-radius:50%;width:43px;height:43px;z-index:10;opacity:0;visibility:hidden;transition:opacity .2s,visibility .2s}.back-top.visible{opacity:1;visibility:visible}
@media(max-width:980px){.shell,.article-wrap{padding-inline:22px}.desktop-nav{display:none}.topbar{height:64px;justify-content:space-between;gap:12px}.brand-note{display:none}.brand{min-width:0;margin-inline:auto}.media--logo,.media--logo img{max-height:30px}.entry-button{height:40px;min-height:40px;padding:7px 12px;font-size:13px}.menu-button{display:none}.js .menu-button{display:flex;flex-direction:column;justify-content:center;align-items:center;gap:5px;border:0;background:transparent;width:40px;height:40px;flex-shrink:0}.menu-button span{width:23px;height:2px;background:var(--navy);border-radius:2px}.mobile-drawer{display:block;position:relative;padding:16px 22px;background:#fff;border-top:1px solid var(--line)}.mobile-drawer .drawer-head{display:none}.mobile-drawer p{font-weight:700;color:var(--muted);font-size:13px;margin:12px 0 4px}.mobile-drawer a{display:inline-block;padding:5px 14px 5px 0;margin-right:12px;font-weight:600}.js .mobile-drawer{position:fixed;left:0;top:0;bottom:0;width:min(86vw,344px);z-index:102;transform:translateX(-105%);visibility:hidden;pointer-events:none;overflow-y:auto;box-shadow:5px 0 26px #0a33552e;transition:transform .23s ease,visibility .23s}.js .mobile-drawer .drawer-head{display:flex;justify-content:space-between;align-items:center;margin-bottom:20px}.js .drawer-close{display:block;border:0;background:var(--pale);border-radius:8px;width:38px;height:38px;font-size:25px;line-height:1}.js .mobile-drawer a{display:block;border-bottom:1px solid var(--line);padding:11px 5px;margin:0}.js .drawer-overlay{display:block;position:fixed;inset:0;background:rgba(9,34,52,.48);opacity:0;visibility:hidden;pointer-events:none;z-index:101;transition:opacity .23s ease,visibility .23s}.js.menu-open .drawer-overlay{opacity:1;visibility:visible;pointer-events:auto}.js.menu-open .mobile-drawer{transform:translateX(0);visibility:visible;pointer-events:auto}body.menu-open{overflow:hidden}.hero{gap:25px}.topic-grid{grid-template-columns:repeat(2,minmax(0,1fr))}.article-layout{grid-template-columns:minmax(0,1fr) 220px;gap:28px}}
@media(max-width:760px){.shell,.article-wrap{padding-inline:16px}.page-section{padding-block:36px}.hero{display:flex;flex-direction:column-reverse;align-items:stretch;padding-top:23px;padding-bottom:32px;gap:20px}.hero h1{font-size:30px}.hero .media--hero{height:220px}.quick-grid{grid-template-columns:1fr;gap:8px}.quick-grid strong{display:inline;margin-right:12px}.editor-grid,.split,.footer-grid,.article-layout{grid-template-columns:1fr}.three-grid,.guide-grid{grid-template-columns:1fr}.article-side{position:static;order:2}.gallery-grid{grid-template-columns:1fr}.step-line{grid-template-columns:repeat(2,minmax(0,1fr))}.page-intro h1{font-size:28px}.page-intro{padding-block:28px 20px}.content-section{padding-block:25px}.media--feature{height:190px}.media--banner{height:155px}.media--mobile{height:290px;max-width:250px}h2{font-size:22px}h3{font-size:18px}body{font-size:15px}.lead{font-size:16px}.footer-grid{gap:24px}}
@media(max-width:640px){.topic-grid{grid-template-columns:1fr}.topic{padding:17px}.media--hero{height:200px}.media--card{height:145px}.hero h1{font-size:28px}.topbar .wordmark{font-size:18px}.wordmark small{font-size:7px}.topbar .entry-button{padding-inline:9px}.panel{padding:19px}.bottom-nav{display:flex;position:fixed;bottom:0;left:0;right:0;min-height:58px;padding-bottom:env(safe-area-inset-bottom,0);z-index:15;background:#fff;box-shadow:0 -2px 14px #174b781e;border-top:1px solid var(--line);justify-content:space-around;align-items:center}.bottom-nav a{flex:1;text-align:center;font-size:13px;font-weight:700;min-height:50px;display:flex;align-items:center;justify-content:center}body{padding-bottom:calc(58px + env(safe-area-inset-bottom,0px))}.back-top{bottom:calc(76px + env(safe-area-inset-bottom,0px))}.footer-bottom{flex-direction:column;align-items:start}}
@media(max-height:500px) and (max-width:640px){.bottom-nav{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}}