:root{--bg:#F4F7FA;--white:#fff;--soft:#EAF1F6;--aqua:#E9F8F8;--nav:#102E46;--deep:#163C57;--teal:#13B8C5;--blue:#237BD3;--heading:#18364B;--text:#344C60;--muted:#64798A;--line:#DCE6ED;--footer:#0B2539;font-family:Arial,'PingFang SC','Microsoft YaHei',sans-serif;color:var(--text);background:var(--bg);scroll-behavior:smooth}*{box-sizing:border-box}html{overflow-x:clip}body{margin:0;min-width:0}a{color:#116d9e;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}img{max-width:100%;height:auto}button{font:inherit;cursor:pointer}h1,h2,h3{color:var(--heading);line-height:1.36;margin:0 0 18px}h1{font-size:36px;letter-spacing:-.035em}h2{font-size:27px}h3{font-size:20px}p,li{line-height:1.8}p{margin:0 0 17px}strong{color:var(--heading)}.container{width:min(100% - 56px,1200px);margin-inline:auto}.readable{max-width:780px}.section{margin-block:58px}.section-tight{margin-block:34px}.eyebrow{font-size:13px;font-weight:700;letter-spacing:.13em;color:#187e8a;margin-bottom:10px}.lead{font-size:18px;line-height:1.78;color:#3c5364}.muted{color:var(--muted)}.section-heading{display:flex;align-items:baseline;justify-content:space-between;gap:20px;border-bottom:1px solid var(--line);padding-bottom:14px;margin-bottom:25px}.section-heading p{margin:0;font-size:14px}.skip-link{position:absolute;left:-9999px;top:8px;z-index:100;background:white;padding:10px}.skip-link:focus{left:12px}.site-header{background:#fff}.brand-bar-inner{height:72px;display:flex;align-items:center;gap:20px}.brand{display:flex;align-items:center;flex:0 0 auto}.brand-caption{font-size:13px;color:#596d7b;margin:0}.brand-caption span{color:#b5c3ce;margin-inline:5px}.entry-link{margin-left:auto;display:inline-flex;align-items:center;justify-content:center;background:var(--nav);color:white;min-height:40px;padding:0 20px;border-radius:9px;font-size:14px;font-weight:700;white-space:nowrap}.entry-link:hover{background:var(--deep);text-decoration:none}.desktop-nav{background:var(--nav)}.desktop-nav-inner{display:flex;justify-content:space-between;gap:8px}.desktop-nav a{color:#dbeaf0;position:relative;white-space:nowrap;display:block;padding:15px 7px;font-size:15px;font-weight:500}.desktop-nav a:hover,.desktop-nav a.is-current{color:white;text-decoration:none;font-weight:700}.desktop-nav .is-current:after{content:'';position:absolute;bottom:6px;left:9px;right:9px;height:3px;background:var(--teal);border-radius:4px}.menu-toggle,.mobile-drawer,.drawer-backdrop,.nojs-nav,.mobile-shortcuts{display:none}.logo-frame{display:flex;align-items:center;justify-content:flex-start;max-width:240px;margin:0;background:transparent;padding:0}.logo-frame img{display:block;max-height:38px;width:auto;height:auto;object-fit:contain}.logo-frame.media-missing{min-width:135px;min-height:35px}.logo-frame.media-missing span{font-size:16px;color:var(--heading);font-weight:800}.crumb{padding-block:20px;display:flex;align-items:center;gap:12px;font-size:13px;color:var(--muted)}.crumb a{color:#4b6c83}.page-intro{padding:35px 0 21px}.page-intro .lead{max-width:830px}.page-intro--tinted{background:var(--soft);padding:40px 0}.page-intro--tinted+.container .section:first-child{margin-top:40px}.chapter-nav{display:flex;flex-wrap:wrap;gap:10px;margin-top:22px}.chapter-nav a,.tag-link{border:1px solid #b7d1df;background:white;border-radius:8px;padding:10px 16px;font-size:14px;color:var(--heading);font-weight:700}.chapter-nav a:hover,.tag-link:hover{background:var(--aqua);text-decoration:none}.hero{display:grid;grid-template-columns:1.04fr .96fr;gap:44px;align-items:center;margin-top:35px}.hero h1{font-size:42px}.hero .lead{font-size:17px}.hero .hero-copy{min-width:0}.button-row{display:flex;gap:12px;flex-wrap:wrap;margin-top:25px}.button{display:inline-flex;align-items:center;justify-content:center;min-height:43px;padding:11px 18px;border-radius:10px;background:var(--nav);color:#fff;font-weight:700;font-size:14px}.button.secondary{background:var(--aqua);border:1px solid #a3d6db;color:var(--nav)}.button:hover{text-decoration:none;filter:brightness(.96)}.media-frame{display:flex;align-items:center;justify-content:center;width:100%;min-width:0;margin:0;background:var(--soft);padding:8px;border-radius:14px;overflow:visible}.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--mobile{--media-limit:350px;max-width:320px}.media-missing{min-height:100px;border:1px dashed #b6cbd8;color:#6a8594;text-align:center;font-size:13px}.media-missing span{padding:12px}.media-frame--hero.media-missing{min-height:220px}.media-frame--mobile.media-missing{min-height:260px}.topic-directory{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));column-gap:44px;row-gap:0}.topic-item{border-top:1px solid var(--line);padding:20px 0 23px;min-width:0}.topic-item span{font-size:12px;color:#168e9b;font-weight:800;letter-spacing:.08em}.topic-item h3{font-size:19px;margin:5px 0 8px}.topic-item p{font-size:15px;margin:0 0 10px}.feature-grid{display:grid;grid-template-columns:2fr 1fr;gap:23px}.feature-main{background:var(--nav);color:#e5f3f7;padding:30px;border-radius:14px}.feature-main h3{color:#fff;font-size:26px}.feature-main p{color:#d5e8f0}.feature-main a{color:#8df3f1}.feature-side{border-top:3px solid var(--teal);background:#fff;padding:25px;border-radius:10px}.feature-side article+article{margin-top:25px;padding-top:22px;border-top:1px solid var(--line)}.editorial-split{display:grid;grid-template-columns:.9fr 1.1fr;gap:36px;align-items:center}.editorial-split.reverse{grid-template-columns:1.15fr .85fr}.editorial-split>*{min-width:0}.three-notes{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:18px;align-items:start}.note{padding:24px;border:1px solid var(--line);background:white;border-radius:12px}.note:nth-child(2){margin-top:22px}.note:nth-child(3){margin-top:44px}.note h3{font-size:19px}.route{counter-reset:route;display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:0;border-top:2px solid var(--deep)}.route article{padding:22px 17px 6px;border-right:1px solid var(--line)}.route article:last-child{border:0}.route article::before{counter-increment:route;content:'0' counter(route);font-size:13px;color:#1396a3;letter-spacing:.12em;font-weight:800}.route h3{font-size:18px;margin-top:8px}.edit-note{border-left:4px solid var(--teal);padding:18px 23px;background:var(--aqua)}.columns-aside{display:grid;grid-template-columns:minmax(0,1fr) 265px;gap:48px}.columns-aside>*{min-width:0}.fact-aside{background:var(--soft);padding:22px;border-radius:12px;align-self:start}.fact-aside ul{padding-left:20px}.chapter{margin:0 0 42px}.chapter>h2{padding-bottom:12px;border-bottom:1px solid var(--line)}.chapter p{max-width:800px}.table-wrap{overflow-x:auto;max-width:100%;border:1px solid var(--line);border-radius:10px;background:white}table{width:100%;border-collapse:collapse;min-width:530px;text-align:left}caption{text-align:left;font-size:15px;font-weight:700;padding:15px;color:var(--heading)}th,td{padding:14px 17px;vertical-align:top;border-bottom:1px solid var(--line);line-height:1.7;font-size:15px}th{background:var(--soft);font-weight:700;color:var(--heading)}tr:last-child td{border-bottom:0}.steps{counter-reset:step;list-style:none;padding:0;display:grid;gap:15px}.steps li{position:relative;padding:16px 20px 16px 66px;background:white;border-left:3px solid var(--teal);border-radius:9px}.steps li:before{counter-increment:step;content:counter(step,decimal-leading-zero);position:absolute;left:20px;top:17px;font-size:16px;color:#147d8a;font-weight:800}.steps strong{display:block}.callout{padding:20px 24px;border-left:4px solid var(--blue);background:var(--soft);border-radius:0 10px 10px 0}.callout p:last-child{margin-bottom:0}.comparison-row{display:grid;grid-template-columns:1fr 1fr;gap:25px}.comparison-row article{background:#fff;border-top:3px solid var(--teal);padding:24px;border-radius:8px}.term-list{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:16px}.term-list article{padding:18px 20px;background:var(--soft);border-radius:10px}.term-list h3{font-size:18px}.matrix-head{background:var(--deep);color:#fff;padding:22px;border-radius:12px 12px 0 0}.matrix-head h2{color:white;margin:0}.matrix-head+.table-wrap{border-radius:0 0 12px 12px}.zigzag article{display:grid;grid-template-columns:1fr 1fr;gap:30px;align-items:start;border-bottom:1px solid var(--line);padding:30px 0}.zigzag article:nth-child(even) .zigzag-text{grid-column:2}.zigzag article:nth-child(even) .zigzag-art{grid-column:1;grid-row:1}.zigzag h3{margin-bottom:10px}.zigzag-art{background:var(--soft);padding:24px;border-radius:12px}.gallery{display:grid;grid-template-columns:1.05fr .95fr;gap:30px}.gallery>*{min-width:0}.gallery .gallery-offset{padding-top:55px}.gallery article{margin-bottom:30px}.gallery h3{margin-top:17px}.rule-sidebar{width:100%;padding:24px;background:var(--soft);border-radius:12px}.rule-sidebar a{display:block;padding:12px 0;border-bottom:1px solid #cbdbe5}.rule-sidebar a:last-child{border:0}.faq details{border-bottom:1px solid var(--line);padding:16px 3px}.faq summary{cursor:pointer;color:var(--heading);font-size:17px;font-weight:700;line-height:1.55}.faq details p{margin:12px 0 0}.service-layout{display:grid;grid-template-columns:250px minmax(0,1fr);gap:42px}.service-nav{align-self:start;background:var(--soft);padding:22px;border-radius:12px}.service-nav a{display:block;padding:10px 0;border-bottom:1px solid #cbdae3}.service-nav a:last-child{border:0}.service-main .chapter{margin-bottom:43px}.related{border-top:1px solid var(--line);padding-top:28px}.related-links{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:12px}.related-links a{display:flex;align-items:center;justify-content:space-between;gap:12px;padding:18px;background:white;border:1px solid var(--line);border-radius:9px;font-weight:700;color:var(--heading)}.related-links a:hover{border-color:var(--teal);text-decoration:none}.site-footer{background:var(--footer);color:#dcecf5;padding:46px 0 0}.footer-layout{display:grid;grid-template-columns:2fr 1fr 1fr;gap:50px}.site-footer p,.site-footer small{color:#dcecf5}.site-footer nav{display:flex;flex-direction:column;gap:12px}.site-footer nav strong{color:#fff;margin-bottom:5px}.site-footer a{color:#dcecf5}.site-footer .logo-frame.media-missing span{color:white}.footer-bottom{border-top:1px solid #325064;padding:20px 0;margin-top:35px;font-size:13px;color:#c2d7df}.back-to-top{position:fixed;bottom:21px;right:20px;width:43px;height:43px;border-radius:50%;border:0;background:var(--deep);color:white;box-shadow:0 3px 14px #0b253933;opacity:0;visibility:hidden;pointer-events:none;transition:opacity .2s}.back-to-top.is-visible{opacity:1;visibility:visible;pointer-events:auto}
@media(max-width:1024px){.container{width:calc(100% - 44px)}.hero{gap:28px}.feature-grid{grid-template-columns:1.7fr 1fr}.columns-aside{gap:28px}}
@media(max-width:920px){.brand-bar-inner{height:62px;display:grid;grid-template-columns:40px minmax(0,1fr) auto;gap:10px}.brand{justify-self:center}.brand-caption,.desktop-nav{display:none}.logo-frame img{max-height:29px}.logo-frame{max-width:180px}.entry-link{min-height:39px;padding:0 12px;margin-left:0;font-size:13px}.menu-toggle{display:flex;flex-direction:column;gap:5px;align-items:center;justify-content:center;width:40px;height:40px;border:1px solid var(--line);border-radius:9px;background:white}.menu-toggle span{width:18px;height:2px;background:var(--nav);border-radius:1px}.mobile-drawer{display:flex;position:fixed;z-index:103;inset:0 auto 0 0;width:min(86vw,340px);height:100dvh;background:white;flex-direction:column;padding:20px 24px;overflow-y:auto;transform:translateX(-102%);visibility:hidden;transition:transform .23s,visibility .23s;box-shadow:6px 0 24px #102e461c}.drawer-head{display:flex;justify-content:space-between;align-items:center;margin-bottom:17px}.drawer-close{border:1px solid var(--line);border-radius:8px;background:white;width:42px;height:42px;font-size:29px;line-height:1}.drawer-label{font-size:12px;letter-spacing:.12em;color:#688091;margin:17px 0 8px;font-weight:700}.mobile-drawer a{display:block;padding:12px;border-radius:8px;color:var(--heading)}.mobile-drawer a.is-current{background:var(--aqua);font-weight:800;border-left:3px solid var(--teal)}.drawer-backdrop{display:block;position:fixed;inset:0;background:#071f30a8;z-index:102;opacity:0;visibility:hidden;pointer-events:none;transition:opacity .23s,visibility .23s}.drawer-open{overflow:hidden}.drawer-open .mobile-drawer{visibility:visible;transform:translateX(0)}.drawer-open .drawer-backdrop{opacity:1;visibility:visible;pointer-events:auto}.nojs-nav{display:flex;flex-wrap:wrap;gap:8px;padding:12px 0}.nojs-nav a{font-size:13px;padding:7px 8px;border:1px solid var(--line);border-radius:6px}.js .nojs-nav{display:none}.mobile-shortcuts{display:flex;gap:9px;justify-content:space-around;flex-wrap:wrap;padding-block:20px;border-top:1px solid var(--line);font-size:13px}.mobile-shortcuts a{color:var(--heading)}.hero h1{font-size:37px}}
@media(max-width:760px){.hero,.editorial-split,.editorial-split.reverse,.feature-grid,.columns-aside,.comparison-row,.gallery,.service-layout{grid-template-columns:1fr}.hero{gap:20px}.hero .media-frame{grid-row:2}.columns-aside aside{order:2}.term-list{grid-template-columns:1fr 1fr}.three-notes{grid-template-columns:1fr;gap:12px}.note:nth-child(2),.note:nth-child(3){margin-top:0}.route{grid-template-columns:1fr 1fr}.route article:nth-child(2){border-right:0}.gallery .gallery-offset{padding-top:0}.zigzag article{grid-template-columns:1fr}.zigzag article:nth-child(even) .zigzag-text,.zigzag article:nth-child(even) .zigzag-art{grid-column:auto;grid-row:auto}.service-main{grid-row:1}.service-nav{grid-row:2}.footer-layout{grid-template-columns:1fr 1fr;gap:27px}.footer-brand{grid-column:1/-1}}
@media(max-width:640px){.container{width:calc(100% - 32px)}h1{font-size:28px}h2{font-size:22px}h3{font-size:18px}p,li{font-size:15px;line-height:1.78}.lead,.hero .lead{font-size:16px}.hero h1{font-size:30px}.section{margin-block:36px}.page-intro{padding-block:24px}.page-intro--tinted{padding-block:26px}.topic-directory,.related-links{grid-template-columns:1fr}.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--mobile{--media-limit:285px;max-width:250px}.media-frame--hero.media-missing{min-height:140px}.topic-item{padding:15px 0}.feature-main,.feature-side{padding:20px}.feature-main h3{font-size:22px}.note{padding:18px}.route{grid-template-columns:1fr}.route article{border-right:0;border-bottom:1px solid var(--line)}.term-list{grid-template-columns:1fr}.table-wrap th,.table-wrap td{padding:11px 12px;font-size:14px}.site-footer{padding-top:35px}.footer-layout{grid-template-columns:1fr}.footer-brand{grid-column:auto}.footer-bottom{margin-top:25px}.crumb{padding-block:15px}.section-heading{display:block}.section-heading p{margin-top:8px}}
@media(prefers-reduced-motion:reduce){*,*::before,*::after{scroll-behavior:auto!important;transition-duration:.01ms!important;animation-duration:.01ms!important}}
