:root{--bg:#F4F7FA;--white:#fff;--pale:#EAF1F6;--mint:#E9F8F8;--navy:#102E46;--deep:#163C57;--cyan:#13B8C5;--blue:#237BD3;--title:#18364B;--body:#344C60;--muted:#64798A;--line:#DCE6ED;--footer:#0B2539;--max:1200px}*{box-sizing:border-box}html{scroll-behavior:smooth;scroll-padding-top:28px}body{margin:0;color:var(--body);background:var(--bg);font-family:Arial,'PingFang SC','Microsoft YaHei',sans-serif;font-size:16px;line-height:1.8;overflow-wrap:break-word}body.menu-open{overflow:hidden}a{color:#1767A9;text-underline-offset:3px}a:hover{color:#087A89}button{font:inherit;cursor:pointer}button:focus-visible,a:focus-visible,summary:focus-visible{outline:3px solid #00A9C7;outline-offset:3px}img{max-width:100%;height:auto}.container{width:min(calc(100% - 56px),var(--max));margin-inline:auto}.skip-link{position:absolute;top:-100px;left:12px;z-index:100;background:#fff;padding:10px}.skip-link:focus{top:10px}.brand-bar{background:#fff;border-bottom:1px solid var(--line)}.brand-inner{min-height:72px;display:flex;align-items:center;gap:22px}.brand{display:inline-flex;align-items:center;min-width:0;color:var(--navy);text-decoration:none}.brand img{height:auto;max-height:38px;width:auto;max-width:225px;object-fit:contain}.brand strong{font-size:23px;white-space:nowrap}.brand small{display:block;font-size:9px;letter-spacing:2px;line-height:1}.brand-desc{font-size:13px;color:var(--muted);border-left:1px solid var(--line);padding-left:20px}.entry-link{margin-left:auto;padding:7px 22px;border-radius:7px;background:var(--navy);color:white;text-decoration:none;font-weight:700;white-space:nowrap}.entry-link:hover{color:white;background:#23627d}.desktop-nav{background:var(--navy)}.nav-inner{display:flex;align-items:stretch;justify-content:space-between;gap:8px;min-height:50px}.nav-inner a{position:relative;display:flex;align-items:center;justify-content:center;flex:1;white-space:nowrap;padding:8px 5px;color:#e5f1f7;text-decoration:none;font-size:14px;font-weight:600}.nav-inner a:hover{background:#1e4a64}.nav-inner a[aria-current=page]{font-weight:800;color:white}.nav-inner a[aria-current=page]::after{content:"";position:absolute;bottom:0;left:25%;right:25%;height:3px;background:var(--cyan)}.menu-toggle,.mobile-drawer,.nav-overlay,.mobile-quick{display:none}.nojs-nav{display:none}.page-main{padding-bottom:55px}.section{margin-block:58px}.section-tight{margin-block:38px}.section-header{display:flex;justify-content:space-between;align-items:end;gap:24px;border-bottom:1px solid var(--line);padding-bottom:14px;margin-bottom:24px}.section-header h2{margin:0}.eyebrow{font-size:12px;font-weight:800;letter-spacing:.12em;color:#007E8B;text-transform:uppercase}.crumb{padding-top:22px;font-size:13px;color:var(--muted)}.crumb a{color:var(--muted)}.crumb span{margin-left:8px}.page-intro{padding:34px 0 18px;max-width:850px}.page-intro p{font-size:17px}.page-intro--tinted{max-width:initial;padding:38px 0;background:var(--pale);margin-top:22px}.page-intro--tinted .reading{max-width:810px}.reading{max-width:780px}.wide-reading{max-width:920px}h1,h2,h3{color:var(--title);line-height:1.38}h1{font-size:35px;margin:10px 0 19px;letter-spacing:-.025em}h2{font-size:27px;margin:0 0 18px}h3{font-size:20px;margin:0 0 12px}p{margin:0 0 16px}p:last-child{margin-bottom:0}.muted{color:var(--muted)}.lead{font-size:18px;color:var(--body)}.cover{padding:52px 0 8px}.cover-grid,.feature-split,.two-col,.side-layout,.split-uneven,.gallery-two{display:grid;gap:36px;align-items:center;grid-template-columns:1fr 1fr;min-width:0}.cover-grid{grid-template-columns:52fr 48fr}.cover h1{font-size:43px;max-width:650px}.cover-copy{max-width:620px}.link-row{display:flex;gap:12px;flex-wrap:wrap;margin-top:25px}.button-link{display:inline-flex;align-items:center;justify-content:center;min-height:43px;padding:8px 19px;border-radius:8px;background:var(--navy);color:#fff;text-decoration:none;font-weight:700}.button-link:hover{color:white;background:#255977}.button-link--light{background:var(--mint);color:var(--navy)}.button-link--light:hover{background:#c9eceb;color:var(--navy)}.media-frame{min-width:0;display:flex;align-items:center;justify-content:center;width:100%;margin:0;padding:10px;border:1px solid var(--line);border-radius:14px;background:var(--pale)}.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--wide{--media-limit:210px}.media-frame--rules{--media-limit:220px}.media-frame--mobile{--media-limit:350px;max-width:320px;margin:auto}.media-frame--empty{min-height:120px;aspect-ratio:2/1;color:#607b8a;font-size:13px;text-align:center;background:repeating-linear-gradient(135deg,#edf3f7,#edf3f7 18px,#e4edf3 18px,#e4edf3 36px)}.media-frame--hero.media-frame--empty{min-height:205px}.topic-directory{border-top:3px solid var(--navy);background:#fff;padding:30px}.topic-index{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:0 36px}.topic-item{display:grid;grid-template-columns:42px 1fr;gap:12px;min-width:0;padding:19px 0;border-bottom:1px solid var(--line)}.topic-num{font-size:20px;font-weight:800;color:#078e99}.topic-item h3{margin:0 0 4px;font-size:18px}.topic-item p{font-size:14px;margin-bottom:8px}.feature-focus{display:grid;grid-template-columns:2fr 1fr;gap:24px}.feature-main{padding:30px;background:var(--navy);color:#e2eff5;border-radius:12px}.feature-main h3{color:#fff;font-size:25px}.feature-main a{color:#8eebf2}.feature-side{display:grid;gap:18px}.feature-side article{border-top:3px solid var(--cyan);padding:16px 18px;background:white}.feature-side h3{font-size:18px}.feature-side p{font-size:14px}.feature-split{grid-template-columns:43fr 57fr}.feature-split.reverse{grid-template-columns:57fr 43fr}.soft-band{background:var(--pale);padding:32px 0}.mint-band{background:var(--mint);padding:32px 0}.three-notes{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:20px}.note{border:1px solid var(--line);border-radius:12px;padding:23px;background:#fff}.note:nth-child(2){transform:translateY(14px)}.note:nth-child(3){transform:translateY(28px)}.note h3{font-size:19px}.steps{counter-reset:stage;display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:12px}.steps article{position:relative;padding:21px;background:#fff;border-top:3px solid var(--cyan)}.steps article::before{counter-increment:stage;content:'0' counter(stage);display:block;color:#058e9a;font-weight:800;margin-bottom:8px}.steps h3{font-size:18px}.steps p{font-size:14px}.editorial-note{border-left:4px solid var(--cyan);padding:20px 25px;background:#fff}.article-chapter{margin:48px 0}.article-chapter>h2{padding-bottom:10px;border-bottom:1px solid var(--line)}.article-chapter h3{margin-top:22px}.text-columns{columns:2;column-gap:36px}.text-columns p{break-inside:avoid}.side-layout{grid-template-columns:minmax(0,1fr) 245px;align-items:start}.side-note{background:var(--pale);padding:23px;border-radius:12px;font-size:14px}.anchor-nav{display:flex;flex-wrap:wrap;gap:10px;margin:12px 0 30px}.anchor-nav a{padding:9px 14px;background:#fff;border:1px solid var(--line);border-radius:7px;text-decoration:none;font-weight:700;font-size:14px}.anchor-nav a:hover{background:var(--mint)}.table-scroll{overflow-x:auto;max-width:100%;border-radius:10px;border:1px solid var(--line);background:white}table{width:100%;border-collapse:collapse;min-width:600px;font-size:15px;line-height:1.65}caption{text-align:left;font-weight:700;padding:14px;color:var(--title)}th,td{padding:13px 17px;text-align:left;vertical-align:top;border-bottom:1px solid var(--line)}th{background:var(--pale);color:var(--title)}tr:last-child td{border-bottom:0}.numbered-vertical{counter-reset:item;display:grid;gap:12px}.numbered-vertical article{counter-increment:item;display:grid;grid-template-columns:48px 1fr;gap:16px;padding:21px;background:white;border-left:3px solid var(--blue)}.numbered-vertical article::before{content:counter(item,decimal-leading-zero);font-size:27px;font-weight:800;color:var(--blue)}.numbered-vertical h3{margin-top:0}.comparison-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:16px}.comparison-grid article{padding:22px;border:1px solid var(--line);border-top:4px solid var(--cyan);background:white;border-radius:8px}.comparison-grid h3{font-size:19px}.tag{display:inline-block;font-size:12px;font-weight:700;background:var(--mint);padding:2px 9px;color:#067582;border-radius:40px}.gallery-two{align-items:start}.gallery-two article{min-width:0}.gallery-two article:nth-child(2){margin-top:55px}.gallery-two h3{margin-top:14px}.article-highlight{padding:30px;background:var(--deep);border-radius:12px;color:#e7f2f7}.article-highlight h2,.article-highlight h3{color:white}.article-highlight a{color:#91ecf2}.faq-list{display:grid;gap:10px}.faq-list details{background:#fff;border:1px solid var(--line);border-radius:9px;padding:14px 18px}.faq-list summary{cursor:pointer;font-weight:700;color:var(--title)}.faq-list details p{padding-top:10px;font-size:15px}.service-layout{display:grid;grid-template-columns:225px minmax(0,1fr);gap:45px;align-items:start}.service-nav{position:sticky;top:24px;padding:23px;background:var(--pale);border-radius:10px}.service-nav a{display:block;margin:8px 0;font-size:14px}.service-body{min-width:0}.related-links{border-top:1px solid var(--line);padding-top:24px;display:flex;gap:12px;flex-wrap:wrap}.related-links a{padding:7px 12px;background:white;border:1px solid var(--line);border-radius:7px;text-decoration:none}.site-footer{background:var(--footer);color:#dcecf5;font-size:14px;padding:43px 0 16px}.footer-grid{display:grid;grid-template-columns:1.4fr 1fr 1fr;gap:44px}.footer-grid strong{display:block;color:white;margin-bottom:12px}.footer-brand{font-size:23px}.footer-brand span{display:block;font-size:10px;letter-spacing:2px}.footer-grid a{color:#d7edf3}.footer-grid nav{display:grid;grid-template-columns:1fr 1fr;gap:6px 10px}.footer-bottom{display:flex;justify-content:space-between;border-top:1px solid #305168;margin-top:28px;padding-top:15px;gap:16px}.back-to-top{border:0;color:#fff;background:transparent;text-decoration:underline}blockquote{margin:24px 0;border-left:4px solid var(--cyan);padding:15px 25px;background:var(--mint);color:var(--title);font-size:18px}ul,ol{padding-left:23px}li{margin-bottom:7px}.plain-list{list-style:none;padding:0}.plain-list li{border-bottom:1px solid var(--line);padding:9px 0}
@media(max-width:1024px){.container{width:min(calc(100% - 44px),var(--max))}.brand-desc{display:none}.cover h1{font-size:38px}.cover-grid,.feature-split{gap:26px}.section{margin-block:47px}.steps{grid-template-columns:repeat(2,minmax(0,1fr))}}
@media(max-width:920px){.brand-inner{min-height:62px;justify-content:space-between;gap:10px}.brand{margin:auto}.brand img{max-height:30px;max-width:min(37vw,195px)}.brand strong{font-size:18px}.entry-link{margin-left:0;padding:7px 10px;font-size:13px;min-height:40px;display:grid;place-items:center}.menu-toggle{display:flex;flex-direction:column;align-items:center;justify-content:center;gap:5px;flex:none;width:40px;height:40px;background:transparent;border:1px solid var(--line);border-radius:6px}.menu-toggle span{display:block;width:18px;height:2px;background:var(--navy)}.desktop-nav{display:none}.mobile-drawer{display:block;position:fixed;z-index:31;left:0;top:0;bottom:0;width:min(86vw,340px);overflow-y:auto;padding:18px 22px;background:white;transform:translateX(-103%);visibility:hidden;transition:transform .22s,visibility .22s;box-shadow:6px 0 24px #092c4230}.mobile-drawer.is-open{visibility:visible;transform:translateX(0)}.drawer-head{display:flex;align-items:center;justify-content:space-between;margin-bottom:15px;color:var(--navy)}.drawer-close{height:40px;width:40px;border:1px solid var(--line);border-radius:6px;background:white;font-size:25px}.drawer-group{font-size:12px;font-weight:800;letter-spacing:.12em;color:var(--muted);margin:20px 0 5px}.mobile-drawer>a{display:block;padding:9px;border-bottom:1px solid var(--line);text-decoration:none;color:var(--title)}.nav-overlay{display:block;position:fixed;inset:0;z-index:30;background:#071a2c85;opacity:0;visibility:hidden;pointer-events:none;transition:opacity .22s,visibility .22s}.nav-overlay.is-open{opacity:1;visibility:visible;pointer-events:auto}.mobile-quick{display:flex;flex-wrap:wrap;gap:8px;justify-content:center;padding:15px 0 25px}.mobile-quick a{font-size:13px;padding:5px 9px;text-decoration:none;border:1px solid var(--line);border-radius:6px}.no-js .menu-toggle{display:none}.no-js .nojs-nav{display:flex;flex-wrap:wrap;justify-content:center;gap:8px;background:var(--navy);padding:9px 16px}.no-js .nojs-nav a{font-size:13px;color:white;padding:4px 8px}}
@media(max-width:760px){.cover-grid,.feature-split,.feature-split.reverse,.two-col,.side-layout,.split-uneven,.gallery-two,.service-layout{grid-template-columns:minmax(0,1fr)}.cover-grid .media-frame{grid-row:2}.feature-focus{grid-template-columns:1fr}.feature-side{grid-template-columns:1fr 1fr}.topic-index{grid-template-columns:1fr}.topic-directory{padding:20px}.three-notes,.comparison-grid{grid-template-columns:1fr}.note:nth-child(2),.note:nth-child(3),.gallery-two article:nth-child(2){transform:none;margin-top:0}.service-nav{position:static;order:2}.service-body{order:1}.footer-grid{grid-template-columns:1fr 1fr}.footer-grid>div:first-child{grid-column:1/-1}.text-columns{columns:1}.cover{padding-top:30px}.page-main{padding-bottom:25px}}
@media(max-width:640px){.container{width:calc(100% - 32px)}body{font-size:15px}.cover h1{font-size:30px}.cover{padding-top:26px}.page-intro{padding-top:24px}.page-intro p{font-size:15px}h1{font-size:27px}h2{font-size:22px}h3{font-size:18px}.section{margin-block:36px}.section-header{align-items:start;display:block}.feature-side,.steps,.footer-grid{grid-template-columns:1fr}.topic-item{grid-template-columns:33px 1fr;gap:8px}.three-notes{gap:12px}.note{padding:18px}.soft-band,.mint-band{padding:18px 0}.media-frame--hero{--media-limit:205px}.media-frame--feature{--media-limit:185px}.media-frame--card{--media-limit:145px}.media-frame--wide{--media-limit:135px}.media-frame--rules{--media-limit:175px}.media-frame--mobile{--media-limit:285px;max-width:250px}.feature-main,.article-highlight{padding:20px}.footer-grid>div:first-child{grid-column:auto}.footer-bottom{flex-wrap:wrap}.numbered-vertical article{grid-template-columns:35px 1fr;padding:15px}.numbered-vertical article::before{font-size:20px}.anchor-nav a{font-size:13px}.section-header h2{margin-bottom:5px}}
@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}*,*:before,*:after{transition-duration:.01ms!important;animation-duration:.01ms!important}}