:root{--bg:#F4F7FA;--white:#fff;--pale:#EAF1F6;--aqua:#E9F8F8;--navy:#102E46;--deep:#163C57;--teal:#13B8C5;--blue:#237BD3;--title:#18364B;--body:#344C60;--muted:#64798A;--line:#DCE6ED;--footer:#0B2539}*{box-sizing:border-box}html{scroll-behavior:smooth;scroll-padding-top:24px}body{margin:0;min-width:0;background:var(--bg);font:16px/1.8 Arial,'PingFang SC','Microsoft YaHei',sans-serif;color:var(--body)}body.drawer-open{overflow:hidden}img{display:block;max-width:100%;height:auto}a{color:#1269ae;text-decoration:none}a:hover{text-decoration:underline}a:focus-visible,button:focus-visible,summary:focus-visible{outline:3px solid var(--teal);outline-offset:3px}button{font:inherit;cursor:pointer}h1,h2,h3,p{margin-top:0}h1,h2,h3{color:var(--title);line-height:1.38}h1{font-size:35px;letter-spacing:-.025em}h2{font-size:26px;margin-bottom:20px}h3{font-size:20px;margin-bottom:12px}p{margin-bottom:17px}ul,ol{padding-left:1.45em}.container{width:min(100% - 56px,1200px);margin-inline:auto}.section{margin-block:60px}.section-slim{margin-block:45px}.eyebrow{font-size:13px;font-weight:700;color:#167987;letter-spacing:.12em;text-transform:uppercase}.lead{font-size:17px;line-height:1.8;color:#4d6578}.small,.muted{color:var(--muted);font-size:14px}.skip-link{position:absolute;top:-70px;left:12px;z-index:300;background:white;padding:10px}.skip-link:focus{top:12px}.site-header{position:relative;z-index:20}.brand-bar{background:#fff;border-bottom:1px solid var(--line)}.brand-layout{height:72px;display:flex;align-items:center;gap:20px}.brand{display:inline-flex;align-items:center;min-width:0;flex-shrink:0}.brand-logo{width:auto;height:auto;max-height:38px;max-width:235px;object-fit:contain}.brand-fallback{font-weight:800;color:var(--navy);font-size:23px;white-space:nowrap}.brand-fallback small{font-size:11px;letter-spacing:.09em;display:block;line-height:1.1}.brand-subtitle{border-left:1px solid var(--line);padding-left:20px;color:var(--muted);font-size:13px}.register-button{margin-left:auto;background:var(--deep);color:#fff;border-radius:10px;min-height:42px;padding:7px 22px;white-space:nowrap;font-weight:700;display:inline-flex;align-items:center;justify-content:center}.register-button:hover{color:white;background:#235477;text-decoration:none}.desktop-nav{background:var(--navy)}.nav-line{display:flex;justify-content:space-between;gap:4px;min-height:50px}.nav-line a{position:relative;padding:11px 13px;color:#e4f3fa;white-space:nowrap;display:flex;align-items:center;font-size:15px}.nav-line a:hover,.nav-line a[aria-current]{color:#fff;text-decoration:none;font-weight:700}.nav-line a[aria-current]:after{content:'';position:absolute;bottom:0;left:13px;right:13px;height:3px;background:var(--teal)}.menu-toggle{display:none}.mobile-drawer,.drawer-overlay,.noscript-nav,.mobile-quick{display:none}.intro-band{background:#fff;border-bottom:1px solid var(--line);padding:42px 0 35px}.intro-band .lead{max-width:820px;margin:0}.crumbs{display:flex;gap:11px;font-size:13px;margin-bottom:17px;color:var(--muted)}.crumbs a{color:#526f82}.page-body{padding-bottom:65px}.story{max-width:790px}.story p{line-height:1.83}.content-panel{background:#fff;border:1px solid var(--line);border-radius:14px;padding:26px}.section-head{display:flex;justify-content:space-between;gap:25px;align-items:end;margin-bottom:20px}.section-head p{max-width:650px;margin:0}.split{display:grid;grid-template-columns:1fr 1fr;gap:36px;align-items:center}.split>*{min-width:0}.split-60{grid-template-columns:minmax(0,1.15fr) minmax(0,.85fr)}.split-40{grid-template-columns:minmax(0,.85fr) minmax(0,1.15fr)}.hero{background:#fff;border-bottom:1px solid var(--line);padding:43px 0 47px}.hero-grid{display:grid;grid-template-columns:52fr 48fr;gap:35px;align-items:center}.hero-grid>*{min-width:0}.hero h1{font-size:42px;line-height:1.32;max-width:630px}.hero .lead{max-width:605px}.action-row{display:flex;flex-wrap:wrap;gap:12px;margin-top:23px}.action{display:inline-flex;min-height:43px;align-items:center;padding:8px 18px;border-radius:9px;border:1px solid var(--deep);font-weight:700}.action.primary{background:var(--deep);color:white}.action.secondary{background:white;color:var(--deep)}.action:hover{text-decoration:none;transform:translateY(-1px)}.media-frame{display:flex;align-items:center;justify-content:center;width:100%;min-width:0;padding:9px;border-radius:14px;background:var(--pale);border:1px solid #e2ebf0;min-height:95px}.media-frame img{display:block;width:auto;height:auto;max-width:100%;max-height:var(--media-limit,220px);object-fit:contain;object-position:center}.media-frame--hero{--media-limit:310px}.media-frame--feature{--media-limit:250px}.media-frame--card{--media-limit:185px}.media-frame--article{--media-limit:220px}.media-frame--wide{--media-limit:210px}.media-frame--mobile{--media-limit:350px;max-width:320px;margin-inline:auto}.media-placeholder{min-height:110px;width:100%;display:flex;justify-content:center;align-items:center;color:#688292;font-size:13px;border:1px dashed #bed1dc;border-radius:8px;background:linear-gradient(130deg,#edf3f7,#dfeef3)}.media-frame--hero .media-placeholder{min-height:230px}.media-frame--mobile .media-placeholder{min-height:230px}.topic-list{display:grid;grid-template-columns:1fr 1fr;gap:0 45px}.topic-item{padding:19px 0;border-top:1px solid var(--line)}.topic-item h3{font-size:19px;margin-bottom:7px}.topic-item 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var(--teal);position:relative}.timeline h3{font-size:18px}.timeline article:before{counter-increment:timeline;content:'0' counter(timeline);display:block;font-weight:800;font-size:26px;color:var(--teal)}.editorial-note{border-left:4px solid var(--teal);background:#fff;padding:22px 26px}.chapter-grid{display:grid;grid-template-columns:minmax(0,1fr) 275px;gap:40px;align-items:start}.sidebar{background:var(--pale);border:1px solid var(--line);padding:24px;border-radius:12px}.sidebar h2{font-size:19px}.sidebar a{display:block;padding:9px 0;border-bottom:1px solid #d0e0e8}.anchor-nav{display:flex;flex-wrap:wrap;gap:10px;margin:25px 0}.anchor-nav a{color:var(--deep);border:1px solid var(--line);background:#fff;border-radius:8px;padding:8px 15px;font-weight:700;font-size:14px}.article-section{margin-block:42px;scroll-margin-top:25px}.article-section>h2{border-bottom:1px solid var(--line);padding-bottom:13px}.table-scroll{overflow-x:auto;max-width:100%;border:1px solid var(--line);border-radius:10px;background:white}table{width:100%;border-collapse:collapse;min-width:560px;font-size:15px;line-height:1.65}caption{text-align:left;font-weight:700;padding:12px 16px;color:var(--title)}th,td{border-bottom:1px solid var(--line);text-align:left;vertical-align:top;padding:13px 16px}thead th{background:var(--pale);color:var(--title)}tbody tr:last-child td{border-bottom:none}.step-list{list-style:none;padding:0;counter-reset:steps}.step-list li{border-left:3px solid var(--teal);margin:0 0 13px;padding:10px 18px;background:#fff}.step-list li:before{counter-increment:steps;content:'步骤 ' counter(steps) ' · ';font-weight:700;color:#087788}.compare-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:15px}.compare-grid article{background:#fff;border:1px solid var(--line);padding:20px;border-radius:10px}.compare-grid h3{font-size:19px}.related-reading{background:#e9f1f6;padding:27px;border-radius:13px;margin:48px 0 0}.related-reading h2{font-size:22px}.related-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:12px}.related-grid a{padding:15px;background:#fff;border-radius:8px;font-weight:700}.gallery-grid{display:grid;grid-template-columns:1fr 1fr;gap:30px;align-items:start}.gallery-grid article:nth-child(2){margin-top:45px}.gallery-grid h3{margin-top:15px}.quote{border-left:4px solid var(--teal);padding:10px 23px;background:var(--aqua);font-size:19px;line-height:1.7;color:var(--title)}.faq-list details{background:#fff;border:1px solid var(--line);border-radius:9px;margin-bottom:10px;padding:0 18px}.faq-list summary{cursor:pointer;font-weight:700;color:var(--title);padding:14px 5px}.faq-list details p{padding:0 5px 15px;margin:0}.service-grid{display:grid;grid-template-columns:250px minmax(0,1fr);gap:38px}.service-aside{align-self:start;background:var(--deep);color:white;padding:24px;border-radius:11px}.service-aside h2{color:white;font-size:19px}.service-aside a{display:block;color:#e5f3fb;padding:8px 0;border-bottom:1px solid #ffffff27}.mobile-quick{display:none}.site-footer{background:var(--footer);color:#dcecf5;padding:42px 0 0}.footer-layout{display:grid;grid-template-columns:2.2fr 1fr 1fr;gap:44px}.footer-brand .footer-logo{max-height:35px;width:auto;max-width:240px;object-fit:contain}.footer-brand .brand-fallback{color:#fff}.footer-layout h2{color:white;font-size:17px;margin-bottom:14px}.footer-layout a{display:block;color:#dcecf5;padding:3px 0}.footer-note{max-width:600px;font-size:13px;opacity:.82}.footer-bottom{border-top:1px solid #ffffff24;margin-top:28px;padding:17px 0;display:flex;justify-content:space-between;gap:20px;font-size:13px}.footer-bottom a{color:#dcecf5}.back-top{position:fixed;bottom:24px;right:24px;z-index:15;border:0;border-radius:50%;background:var(--deep);color:white;width:43px;height:43px;box-shadow:0 3px 15px #0003}.back-top[hidden]{display:none}section[id]{scroll-margin-top:24px}
@media(max-width:1024px){.container{width:min(100% - 44px,1200px)}.brand-subtitle{font-size:12px}.nav-line a{padding-inline:9px;font-size:14px}.section{margin-block:50px}.split{gap:24px}}
@media(max-width:920px){.brand-layout{height:62px;display:grid;grid-template-columns:44px minmax(0,1fr) auto;gap:10px;position:relative}.brand{justify-self:center}.brand-logo{max-height:30px;max-width:min(38vw,185px)}.brand-fallback{font-size:19px}.brand-fallback small{font-size:9px}.brand-subtitle,.desktop-nav{display:none}.register-button{margin:0;min-height:40px;padding:6px 11px;font-size:13px}.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:9px}.menu-toggle span{display:block;width:19px;height:2px;background:var(--navy)}.drawer-overlay{display:block;position:fixed;inset:0;z-index:60;background:#061c2cb0;opacity:0;visibility:hidden;pointer-events:none;transition:opacity .2s,visibility .2s}.drawer-overlay.is-open{opacity:1;visibility:visible;pointer-events:auto}.mobile-drawer{display:block;position:fixed;z-index:61;inset:0 auto 0 0;width:min(86vw,340px);max-width:100%;overflow-y:auto;background:#fff;box-shadow:7px 0 24px #0002;transform:translateX(-103%);visibility:hidden;pointer-events:none;transition:transform .2s,visibility .2s;padding:18px 21px}.mobile-drawer.is-open{transform:translateX(0);visibility:visible;pointer-events:auto}.drawer-head{display:flex;align-items:center;justify-content:space-between;border-bottom:1px solid var(--line);padding-bottom:12px}.drawer-close{border:1px solid var(--line);background:#f5f8fa;width:40px;height:40px;border-radius:8px;font-size:28px;line-height:1}.drawer-group{margin-top:20px}.drawer-group h2{font-size:13px;color:var(--muted);letter-spacing:.1em;margin-bottom:4px}.drawer-group a{display:block;border-bottom:1px solid var(--line);padding:10px;color:var(--deep);font-weight:700}.noscript-nav{display:flex;flex-wrap:wrap;gap:10px;padding:10px 18px;background:#eaf1f6}.noscript-nav a{padding:3px 5px}.mobile-quick{display:flex;justify-content:space-between;gap:8px;flex-wrap:wrap;padding:20px 0}.mobile-quick a{font-size:13px}.service-grid{grid-template-columns:1fr}.service-aside{order:2}.service-main{order:1}}
@media(max-width:760px){.container{width:min(100% - 36px,1200px)}.hero-grid,.split,.split-60,.split-40,.chapter-grid,.focus-grid,.gallery-grid{grid-template-columns:1fr}.hero{padding:32px 0}.hero-grid{gap:24px}.topic-list{grid-template-columns:1fr}.chapter-grid{gap:20px}.sidebar{order:2}.three-notes,.compare-grid,.related-grid{grid-template-columns:1fr}.three-notes article:nth-child(n),.gallery-grid article:nth-child(2){margin-top:0}.timeline{grid-template-columns:1fr 1fr}.focus-side{grid-template-columns:1fr 1fr}.footer-layout{grid-template-columns:1fr 1fr;gap:28px}.footer-layout>div:first-child{grid-column:1/-1}.intro-band{padding:32px 0}.section{margin-block:40px}}
@media(max-width:640px){body{font-size:15px;line-height:1.78}.container{width:min(100% - 32px,1200px)}h1{font-size:27px}h2{font-size:22px}h3{font-size:18px}.hero h1{font-size:30px}.lead{font-size:16px}.section{margin-block:34px}.content-panel{padding:17px}.anchor-nav{gap:6px}.anchor-nav a{font-size:13px;padding:7px 10px}.focus-side{grid-template-columns:1fr}.timeline{grid-template-columns:1fr}.media-frame--hero{--media-limit:205px}.media-frame--feature{--media-limit:185px}.media-frame--article{--media-limit:175px}.media-frame--card{--media-limit:145px}.media-frame--wide{--media-limit:135px}.media-frame--mobile{--media-limit:285px;max-width:250px}.media-frame--hero .media-placeholder{min-height:170px}.hero-grid{gap:18px}.intro-band{padding:25px 0}.section-head{display:block}.footer-layout{grid-template-columns:1fr 1fr;gap:18px}.footer-layout a{font-size:14px}.footer-bottom{flex-wrap:wrap}.quote{font-size:17px}.related-reading{padding:18px}.table-scroll{margin-inline:0}}
@media(max-width:380px){.brand-logo{max-width:35vw}.brand-fallback{font-size:16px}.register-button{font-size:12px;padding-inline:9px}.brand-layout{gap:5px}.action{font-size:14px}}
@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}*,*:before,*:after{transition:none!important;animation:none!important}}