:root{--bg:#F4F7FA;--paper:#fff;--soft:#EAF1F6;--mint:#E9F8F8;--nav:#102E46;--deep:#163C57;--brand:#13B8C5;--blue:#237BD3;--heading:#18364B;--body:#344C60;--muted:#64798A;--line:#DCE6ED;--width:1200px}*{box-sizing:border-box}html{scroll-behavior:smooth;scroll-padding-top:22px}body{margin:0;background:var(--bg);color:var(--body);font:16px/1.8 Arial,"PingFang SC","Microsoft YaHei",sans-serif;overflow-wrap:break-word}a{color:#09659D;text-decoration:none}a:hover{text-decoration:underline}a:focus-visible,button:focus-visible,summary:focus-visible{outline:3px solid #13B8C5;outline-offset:3px}button{font:inherit;cursor:pointer}img{max-width:100%;height:auto}h1,h2,h3,h4{color:var(--heading);line-height:1.38;margin:0 0 .7em}h1{font-size:clamp(32px,3.1vw,36px);letter-spacing:-.025em}h2{font-size:clamp(23px,2.3vw,27px)}h3{font-size:20px}p{margin:.3em 0 1.25em}ul,ol{padding-left:1.4em}li{margin-bottom:.45em}.container{width:min(calc(100% - 56px),var(--width));margin-inline:auto}.reading{max-width:790px}.section{margin-block:60px}.section--tight{margin-block:40px}.eyebrow{display:block;font-size:12px;font-weight:800;letter-spacing:.16em;text-transform:uppercase;color:#187B92;margin-bottom:10px}.lead{font-size:17px;line-height:1.85;color:#3E586D;max-width:800px}.muted{color:var(--muted)}.rule-line{height:1px;background:var(--line);margin:22px 0}.kicker{color:#137C90;font-weight:700;font-size:14px}.article-body p{max-width:790px}.article-body h2{margin-top:2.2em}.article-body h3{margin-top:1.7em}.pill-link,.button-link{display:inline-flex;align-items:center;justify-content:center;min-height:43px;padding:8px 20px;background:var(--nav);color:white;border-radius:9px;font-weight:700;text-decoration:none}.pill-link:hover,.button-link:hover{background:#225476;text-decoration:none}.button-link--outline{background:white;border:1px solid #AACBD8;color:var(--deep)}.button-link--outline:hover{background:var(--soft)}.button-row{display:flex;flex-wrap:wrap;gap:12px;margin-top:22px}.text-link{font-weight:700;border-bottom:1px solid currentColor}.skip-link{position:absolute;top:-60px;left:12px;background:white;padding:8px 12px;z-index:300}.skip-link:focus{top:10px}.site-header{position:relative;z-index:30}.brand-bar{background:#fff;border-bottom:1px solid var(--line)}.brand-bar__inner{height:72px;display:flex;align-items:center;gap:22px}.brand-mark{display:flex;align-items:center;flex:0 1 auto;min-width:0;color:var(--heading)}.brand-mark:hover{text-decoration:none}.brand-mark .media-frame{background:transparent;padding:0;border:0;width:auto;max-width:210px}.brand-mark img{max-height:38px;max-width:210px}.brand-fallback{display:none;font-size:17px;font-weight:800;letter-spacing:.09em}.brand-mark:has(.media-missing) .media-frame{display:none}.brand-mark:has(.media-missing) .brand-fallback{display:block}.brand-desc{font-size:13px;color:var(--muted);margin:0;border-left:1px solid var(--line);padding-left:19px;white-space:nowrap}.brand-desc span{color:#b7c7d0;margin:0 6px}.register-link{margin-left:auto;min-height:40px;white-space:nowrap;padding:8px 20px;background:var(--brand);border-radius:9px;color:#062B35;font-weight:800}.register-link:hover{background:#41D2DC;text-decoration:none}.desktop-nav{background:var(--nav)}.desktop-nav__inner{height:50px;display:grid;grid-template-columns:repeat(7,minmax(0,1fr));align-items:stretch}.desktop-nav a{display:flex;align-items:center;justify-content:center;color:#E6F3FA;font-size:14px;font-weight:500;position:relative;white-space:nowrap}.desktop-nav a:hover,.desktop-nav a[aria-current]{background:#163C57;color:white;text-decoration:none;font-weight:800}.desktop-nav a[aria-current]:after{content:"";position:absolute;bottom:0;left:22%;right:22%;height:3px;background:var(--brand)}.menu-toggle,.mobile-drawer,.drawer-overlay,.mobile-quick-links{display:none}.nojs-nav{display:flex;gap:16px;flex-wrap:wrap;padding:12px 0}.breadcrumbs{font-size:13px;color:var(--muted);margin:30px 0 24px}.breadcrumbs a{color:#48718B}.breadcrumbs span{margin:0 8px}.page-intro{padding:44px 0 16px}.page-intro .lead{max-width:820px}.media-frame{--media-limit:220px;display:flex;align-items:center;justify-content:center;min-width:0;width:100%;padding:8px;border-radius:14px;background:var(--soft);overflow:hidden}.media-frame img{display:block;width:auto;height:auto;max-width:100%;max-height:var(--media-limit);object-fit:contain;object-position:center}.media-frame--logo{--media-limit:38px}.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:auto}.media-missing{min-height:110px;border:1px dashed #B7CAD6;color:#667C8B;font-size:13px;text-align:center}.media-frame--hero.media-missing{min-height:200px}.media-frame--logo.media-missing{min-height:0;padding:0}.media-frame--mobile.media-missing{min-height:180px}.section-nav{display:flex;align-items:center;gap:24px;flex-wrap:wrap;background:#fff;border-block:1px solid var(--line);padding:14px 18px;margin:28px 0}.section-nav strong{font-size:13px;color:var(--heading);white-space:nowrap}.section-nav__links{display:flex;gap:12px 22px;flex-wrap:wrap}.section-nav a{font-size:14px;font-weight:700}.section-header{display:flex;justify-content:space-between;align-items:end;gap:20px;margin-bottom:22px;border-bottom:1px solid var(--line);padding-bottom:17px}.section-header h2{margin:0}.section-header p{margin:0;max-width:530px}.split{display:grid;grid-template-columns:minmax(0,1fr) minmax(0,1fr);gap:38px;align-items:center}.split>*{min-width:0}.split--wide-text{grid-template-columns:minmax(0,1.3fr) minmax(0,.7fr)}.split--narrow-img{grid-template-columns:minmax(0,.7fr) minmax(0,1.3fr)}.panel{background:#fff;border:1px solid var(--line);border-radius:13px;padding:24px;min-width:0}.panel--tint{background:var(--mint)}.panel--deep{background:var(--deep);color:#E9F3FA;border-color:var(--deep)}.panel--deep h2,.panel--deep h3{color:#fff}.panel--deep a{color:#8DE9EF}.note{border-left:4px solid var(--brand);background:var(--mint);padding:18px 22px;margin:22px 0}.note p:last-child{margin-bottom:0}.topic-index{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:0 36px}.topic-item{padding:21px 4px;border-top:1px solid var(--line)}.topic-item h3{margin:0 0 8px}.topic-item h3 a{color:var(--heading)}.topic-item p{margin:0;font-size:15px}.feature-grid{display:grid;grid-template-columns:minmax(0,2fr) minmax(0,1fr);gap:18px}.feature-side{display:grid;gap:18px}.feature-side .panel{padding:22px}.feature-main{padding:30px 32px;background:var(--deep);color:#E8F4FA;border-radius:12px}.feature-main h3{font-size:25px;color:white}.feature-main a{color:#91EDF1}.lesson-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:18px;align-items:start}.lesson-grid>*:nth-child(2){margin-top:22px}.lesson-grid>*:nth-child(3){margin-top:44px}.steps{counter-reset:step;display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:15px;padding:0;list-style:none}.steps li{background:white;border-top:3px solid var(--brand);padding:20px;border-radius:0 0 10px 10px;min-width:0}.steps li::before{counter-increment:step;content:"0" counter(step);display:block;font-size:13px;font-weight:800;color:#147C93;margin-bottom:10px}.steps li strong{display:block;color:var(--heading)}.steps li p{font-size:14px;margin:9px 0}.page-section{margin:56px 0}.section-heading{border-bottom:1px solid var(--line);margin-bottom:22px;padding-bottom:12px}.two-column-article{display:grid;grid-template-columns:minmax(0,2fr) minmax(220px,.8fr);gap:36px;align-items:start}.sidebar{background:var(--soft);border-radius:12px;padding:23px;font-size:14px}.sidebar h3{font-size:16px}.sidebar ul{padding-left:18px}.table-scroll{overflow-x:auto;max-width:100%;margin:24px 0;border:1px solid var(--line);border-radius:12px;background:white}table{width:100%;border-collapse:collapse;min-width:580px;font-size:15px;line-height:1.65}caption{text-align:left;font-weight:800;color:var(--heading);padding:14px 18px;background:var(--soft)}th,td{padding:13px 16px;text-align:left;border-bottom:1px solid var(--line);vertical-align:top}thead th{background:#EAF1F6;color:var(--heading);font-weight:800}tbody tr:last-child td,tbody tr:last-child th{border-bottom:0}.process-list{list-style:none;padding:0;margin:20px 0;border-left:2px solid #C2E6E8}.process-list li{position:relative;padding:0 0 26px 30px}.process-list li:before{content:"";position:absolute;width:13px;height:13px;border-radius:100%;background:var(--brand);left:-8px;top:9px}.process-list li strong{display:block;color:var(--heading);font-size:19px}.process-list li p{margin:6px 0}.article-figure{margin:22px 0 30px}.article-figure figcaption{font-size:13px;color:var(--muted);padding:8px 4px}.callout-row{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:18px}.callout-row article{border-top:3px solid var(--brand);padding:18px 3px}.gallery{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:32px;align-items:start}.gallery article:nth-child(even){margin-top:48px}.gallery figure{margin:0 0 18px}.gallery figcaption{font-size:13px;color:var(--muted);margin-top:8px}.matrix{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:15px}.matrix article{padding:22px;background:white;border:1px solid var(--line);border-top:4px solid var(--brand);border-radius:10px}.matrix p{font-size:15px}.faq-list{max-width:850px}.faq{background:white;border-bottom:1px solid var(--line);padding:0 18px}.faq:first-child{border-top:1px solid var(--line)}.faq summary{font-weight:700;color:var(--heading);cursor:pointer;padding:16px 18px 16px 0}.faq summary:hover{color:#087596}.faq p{padding:0 15px 18px 0;margin:0}.support-layout{display:grid;grid-template-columns:240px minmax(0,1fr);gap:40px;align-items:start}.support-side{position:sticky;top:20px;background:var(--soft);padding:24px;border-radius:12px}.support-side a{display:block;padding:8px 0;border-bottom:1px solid #cedde6}.support-body{min-width:0}.references{border-top:1px solid var(--line);padding-top:20px;margin-top:35px}.references a{display:inline-block;margin-right:19px;margin-bottom:10px;font-weight:700}.cover{margin-top:30px;display:grid;grid-template-columns:minmax(0,1.08fr) minmax(0,1fr);gap:32px;align-items:center;padding:36px 0 15px}.cover h1{font-size:clamp(30px,3.5vw,43px)}.cover p{max-width:590px}.cover .media-frame{background:#E8F1F3}.cover .media-frame img{max-height:310px}.mini-label{font-size:12px;font-weight:800;text-transform:uppercase;letter-spacing:.12em;color:#0D7B92}.site-footer{background:#0B2539;color:#DCECF5;margin-top:62px;font-size:14px}.footer-main{padding:47px 0 35px;display:grid;grid-template-columns:minmax(0,1.4fr) minmax(0,1fr);gap:60px}.footer-brand{font-size:21px;font-weight:800;color:white}.footer-brand span{font-size:12px;letter-spacing:.12em;margin-left:12px;color:#87C7D8}.footer-note{max-width:610px;font-size:13px}.site-footer nav{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:3px 18px}.site-footer nav strong{grid-column:1/-1;color:#fff}.site-footer a{color:#DCECF5}.footer-bottom{border-top:1px solid #315064;padding:17px 0;display:flex;flex-wrap:wrap;gap:16px;justify-content:space-between;font-size:12px;color:#B8CFDB}.back-top{position:fixed;right:20px;bottom:20px;background:#102E46;color:white;border:0;border-radius:50%;width:44px;height:44px;z-index:15}.back-top[hidden]{display:none}
@media(max-width:1100px){.brand-desc{font-size:12px}.container{width:calc(100% - 44px)}}
@media(max-width:920px){.container{width:calc(100% - 44px)}.brand-bar__inner{height:62px;display:grid;grid-template-columns:40px minmax(0,1fr) auto;gap:12px}.menu-toggle{display:flex;width:40px;height:40px;align-items:center;justify-content:center;flex-direction:column;gap:5px;background:white;border:1px solid var(--line);border-radius:9px}.menu-toggle span{width:19px;height:2px;background:var(--nav)}.brand-mark{justify-content:center}.brand-mark img{max-height:30px;max-width:min(100%,180px)}.brand-desc,.desktop-nav{display:none}.register-link{margin-left:0;font-size:13px;padding:8px 10px;min-height:39px}.drawer-overlay{display:block;position:fixed;inset:0;background:rgba(6,24,38,.53);opacity:0;visibility:hidden;pointer-events:none;border:0;padding:0;z-index:70;transition:opacity .2s ease,visibility .2s ease}.mobile-drawer{display:block;position:fixed;left:0;top:0;bottom:0;width:min(86vw,340px);background:white;z-index:71;transform:translateX(-103%);visibility:hidden;pointer-events:none;transition:transform .24s ease,visibility .24s ease;overflow-y:auto;box-shadow:8px 0 20px rgba(0,0,0,.1)}.drawer-open{overflow:hidden}.drawer-open .mobile-drawer{transform:translateX(0);visibility:visible;pointer-events:auto}.drawer-open .drawer-overlay{opacity:1;visibility:visible;pointer-events:auto}.drawer-top{display:flex;align-items:center;justify-content:space-between;padding:16px 20px;background:var(--soft);color:var(--heading);letter-spacing:.07em;font-size:14px}.drawer-close{border:1px solid var(--line);background:white;border-radius:9px;width:40px;height:40px;font-size:24px;line-height:1}.drawer-group{display:grid;padding:17px 22px;border-bottom:1px solid var(--line)}.drawer-group span{font-size:12px;text-transform:uppercase;color:var(--muted);font-weight:800;letter-spacing:.1em}.drawer-group a{display:block;padding:9px 0;color:var(--heading);font-weight:700}.mobile-quick-links{display:flex;flex-wrap:wrap;gap:14px;justify-content:center;padding:20px 0 0;font-size:14px}.cover{gap:20px}}
@media(max-width:760px){.split,.split--wide-text,.split--narrow-img,.two-column-article,.feature-grid,.support-layout,.gallery{grid-template-columns:minmax(0,1fr)}.cover{grid-template-columns:minmax(0,1fr)}.cover .cover-text{order:0}.cover .cover-image{order:1}.feature-main{padding:25px}.lesson-grid,.matrix,.callout-row{grid-template-columns:repeat(2,minmax(0,1fr))}.lesson-grid>*:nth-child(n){margin-top:0}.gallery article:nth-child(n){margin-top:0}.support-side{order:2;position:static}.support-body{order:1}.steps{grid-template-columns:repeat(2,minmax(0,1fr))}.footer-main{grid-template-columns:1fr;gap:22px}.section{margin-block:42px}.page-section{margin:42px 0}}
@media(max-width:640px){body{font-size:15px}.container{width:calc(100% - 32px)}h1{font-size:clamp(25px,6.8vw,29px)}.cover h1{font-size:clamp(27px,7.4vw,32px)}h2{font-size:21px}h3{font-size:18px}.lead{font-size:15px}.cover{margin-top:16px;padding:15px 0}.panel{padding:18px}.section{margin-block:36px}.page-intro{padding:26px 0 6px}.breadcrumbs{margin:18px 0 12px}.topic-index,.lesson-grid,.matrix,.callout-row,.steps{grid-template-columns:1fr}.feature-main h3{font-size:21px}.media-frame--logo{--media-limit:30px}.media-frame--hero{--media-limit:205px}.media-frame--feature{--media-limit:185px}.media-frame--card{--media-limit:145px}.media-frame--article{--media-limit:175px}.media-frame--wide{--media-limit:135px}.media-frame--mobile{--media-limit:285px;max-width:250px}.media-frame--hero.media-missing{min-height:125px}.media-missing{min-height:90px}.section-nav{padding:12px;gap:6px}.section-nav__links{gap:7px 15px}.section-header{display:block}.footer-main{padding:32px 0 24px}.footer-brand span{display:block;margin-left:0}.site-footer nav{grid-template-columns:1fr}.brand-mark img{max-width:min(100%,145px)}.brand-fallback{font-size:13px}.register-link{padding:7px 8px}.table-scroll{margin:18px 0}}
@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}*,*:before,*:after{animation-duration:.01ms!important;transition-duration:.01ms!important}}
