:root{--bg:#F6FAFC;--white:#fff;--soft:#EAF6FA;--soft2:#EDF4F8;--cyan:#25C8D1;--sky:#25B6E8;--blue:#1787DB;--navy:#174B78;--heading:#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);color:var(--body);font-family:Arial,'PingFang SC','Microsoft YaHei',sans-serif;font-size:16px;line-height:1.8;overflow-x:hidden}img{max-width:100%}a{color:var(--navy);text-underline-offset:4px}a:hover{color:var(--blue)}a:focus-visible,button:focus-visible,summary:focus-visible{outline:3px solid var(--cyan);outline-offset:3px}h1,h2,h3,p{margin-top:0}h1,h2,h3{color:var(--heading);line-height:1.38;letter-spacing:-.02em}h1{font-size:clamp(32px,3.3vw,42px);margin-bottom:20px}h2{font-size:26px;margin-bottom:18px}h3{font-size:20px;margin-bottom:12px}p{margin-bottom:16px}.wrap{width:min(100% - 56px,1180px);margin-inline:auto}.section{margin-block:58px}.section-heading{margin-bottom:24px}.eyebrow{display:block;color:#087B96;font-size:12px;font-weight:800;letter-spacing:.16em;margin-bottom:9px}.lead{font-size:17px;line-height:1.85}.muted{color:var(--muted)}.tag{display:inline-block;background:#DDF5F7;color:#136A85;padding:4px 11px;border-radius:6px;font-size:13px;font-weight:700}.site-header{background:white;border-bottom:1px solid var(--line);position:relative;z-index:20}.brandbar{display:flex;align-items:center;gap:25px;height:72px}.brand{text-decoration:none;display:flex;align-items:center;min-width:0;max-width:250px}.brand img{display:block;width:auto;height:auto;max-height:38px;max-width:220px;object-fit:contain;object-position:left center}.brand-text{font-size:24px;font-weight:900;color:var(--navy);line-height:1.12;white-space:nowrap}.brand-text 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strong{display:block;color:var(--heading);font-size:17px;margin-bottom:5px}.anchor-nav{display:flex;flex-wrap:wrap;gap:11px;margin:5px 0 32px}.anchor-nav a{padding:8px 14px;background:#EAF6FA;border:1px solid var(--line);border-radius:8px;text-decoration:none;font-weight:700}.rule-section{background:white;border:1px solid var(--line);padding:28px;border-radius:16px;margin:22px 0 36px}.rule-section h2{margin-top:0}.faq-list{border-top:1px solid var(--line)}.faq-list details{border-bottom:1px solid var(--line);background:white}.faq-list summary{cursor:pointer;font-weight:700;color:var(--heading);padding:16px 42px 16px 18px;list-style:none;position:relative}.faq-list summary::-webkit-details-marker{display:none}.faq-list summary::after{content:'+';position:absolute;right:19px;font-size:22px;top:10px;color:var(--blue)}.faq-list details[open] summary::after{content:'−'}.faq-answer{padding:0 18px 17px}.faq-answer 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@media(max-width:760px){.wrap{width:min(100% - 32px,1180px)}.section{margin-block:36px}.hero{grid-template-columns:1fr;gap:22px;padding-top:30px}.hero>.media{grid-row:1}.hero-copy h1{font-size:30px}.media--hero{height:220px}.media--feature{height:190px}.media--card{height:150px}.media--banner{height:160px}.media--mobile{height:290px;max-width:250px}.media--wide{height:145px}.page-heading{padding-top:34px}.page-heading h1{font-size:29px}.editor-grid,.split-section,.page-layout,.footer-layout{grid-template-columns:1fr}.split-section.reverse>.media{order:0}.topic-grid{grid-template-columns:repeat(2,minmax(0,1fr))}.small-index,.matrix,.info-grid,.related-grid{grid-template-columns:1fr 1fr}.aside-panel{position:static}.gallery-grid{grid-template-columns:1fr 1fr}.steps{grid-template-columns:repeat(2,1fr)}.footer-layout{gap:30px}.mobile-bottom{display:grid;grid-template-columns:repeat(4,1fr);position:fixed;bottom:0;left:0;right:0;z-index:12;background:#fff;border-top:1px solid var(--line);padding-bottom:env(safe-area-inset-bottom,0px);box-shadow:0 -3px 15px #173b5c12}.mobile-bottom a{font-size:13px;text-align:center;text-decoration:none;font-weight:700;padding:12px 2px;min-height:44px}.mobile-bottom a[aria-current=page]{color:#087B96;border-top:3px solid var(--cyan);padding-top:9px}body{padding-bottom:calc(47px + env(safe-area-inset-bottom,0px))}.to-top{bottom:76px;right:15px}}
@media(max-width:640px){h2{font-size:22px}h3{font-size:18px}body{font-size:15px}.lead{font-size:16px}.hero-copy h1{font-size:29px}.topic-grid,.small-index,.matrix,.info-grid,.info-grid.two,.gallery-grid,.related-grid{grid-template-columns:1fr}.topic-card{padding:18px}.feature-story,.side-story,.panel,.surface,.rule-section{padding:19px}.page-heading h1{font-size:27px}.section-heading{margin-bottom:16px}.quickbar-content{gap:8px;padding:10px 0}.quickbar-content>span{gap:7px}.steps{grid-template-columns:1fr 1fr}.steps li{padding:16px}.footer-brand span{display:block;margin:3px 0 0}.article-body section{margin-bottom:34px}.brand{max-width:38%}}
@media(max-height:540px) and (max-width:760px){.mobile-bottom{position:static}body{padding-bottom:0}.to-top{bottom:18px}}
@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}*,*::before,*::after{transition:none!important;animation:none!important}}