:root{--bg:#f6fafc;--white:#fff;--light:#eaf6fa;--light2:#edf4f8;--cyan:#25c8d1;--sky:#25b6e8;--blue:#1787db;--navy:#174b78;--title:#183a56;--body:#31485d;--muted:#687d8e;--line:#dce9f0;--footer:#123653;--shadow:0 9px 30px rgba(17,64,96,.055)}
*{box-sizing:border-box}html{scroll-behavior:smooth;scroll-padding-top:30px}body{margin:0;font:16px/1.8 Arial,'PingFang SC','Microsoft YaHei',sans-serif;color:var(--body);background:var(--bg);overflow-wrap:break-word}body.drawer-open{overflow:hidden}a{color:#146caa;text-decoration-thickness:1px;text-underline-offset:3px}a:hover{color:#075886}button{font:inherit;cursor:pointer}button:focus-visible,a:focus-visible,summary:focus-visible{outline:3px solid var(--cyan);outline-offset:3px}h1,h2,h3,h4{line-height:1.37;color:var(--title);letter-spacing:-.02em}h1{font-size:clamp(25px,3.3vw,36px);margin:0 0 22px}h2{font-size:clamp(21px,2.4vw,27px);margin:0 0 20px}h3{font-size:clamp(17px,1.9vw,21px);margin:0 0 10px}p{margin:0 0 15px}strong{color:var(--title)}.wrap{width:min(1180px,calc(100% - 56px));margin-inline:auto}.narrow{max-width:780px}.section{padding:56px 0}.section.tight{padding:32px 0}.section-alt{background:var(--light2)}.section-white{background:#fff}.section-lead{max-width:810px;margin:0 0 25px;color:var(--muted)}.eyebrow{display:block;text-transform:uppercase;letter-spacing:.12em;font-size:12px;font-weight:800;color:#087b91;margin-bottom:10px}.small{font-size:13px;color:var(--muted)}.kicker{color:#187da8;font-weight:700;font-size:14px}.page-intro{padding:53px 0 24px}.page-intro p{max-width:830px;font-size:17px}.page-intro.compact{padding-bottom:12px}.divider{height:1px;background:var(--line);margin:26px 0}.skip-link{position:absolute;top:-100px;left:12px;z-index:100;background:#fff;padding:10px}.skip-link:focus{top:8px}.site-header{background:#fff;border-bottom:1px solid var(--line)}.topbar{height:72px;display:flex;align-items:center;gap:20px}.brand{text-decoration:none;display:inline-flex;align-items:center;min-width:180px}.brand-fallback{font-size:25px;font-weight:900;color:var(--navy);white-space:nowrap;line-height:1}.brand-fallback small,.footer-brand small{font-size:10px;letter-spacing:.12em;display:block;margin-top:7px;color:#2e849c}.topbar-subtitle{margin:auto;color:#607a8c;font-size:14px;letter-spacing:.07em}.entry-button{display:inline-flex;justify-content:center;align-items:center;gap:9px;background:var(--navy);color:white;text-decoration:none;border-radius:10px;font-size:14px;font-weight:700;min-height:44px;padding:0 24px;white-space:nowrap}.entry-button:hover{color:white;background:#0f3a60}.desktop-nav{background:var(--navy)}.nav-scroll{display:flex;align-items:stretch;justify-content:space-between;gap:15px;min-height:48px}.desktop-nav a{color:#e9f5fb;white-space:nowrap;display:flex;align-items:center;justify-content:center;text-decoration:none;font-size:14px;padding:0 9px;border-bottom:3px solid transparent}.desktop-nav a:hover,.desktop-nav a.active{color:#fff;border-bottom-color:#61e2e8}.menu-toggle{display:none;border:0;background:transparent;flex:0 0 40px;width:40px;height:40px;padding:9px}.menu-toggle span{height:2px;background:var(--navy);display:block;margin:5px 0}.drawer-backdrop,.mobile-drawer,.mobile-bottom{display:none}.hero{display:grid;grid-template-columns:minmax(0,1.12fr) minmax(0,.88fr);align-items:center;gap:46px;padding:57px 0 50px}.hero h1{font-size:clamp(28px,3.65vw,42px)}.hero p{font-size:17px}.hero-actions{display:flex;gap:13px;flex-wrap:wrap;margin-top:24px}.btn{background:var(--navy);color:#fff;text-decoration:none;display:inline-flex;justify-content:center;align-items:center;min-height:45px;padding:9px 23px;border-radius:10px;font-weight:700;font-size:14px}.btn:hover{color:white;background:#0b3d64}.btn-outline{color:var(--navy);background:#fff;border:1px solid #bddbe7}.btn-outline:hover{color:#0d4f7c;background:var(--light)}.quick-topics{padding:16px 0;border-block:1px solid var(--line);background:white}.quick-topics .wrap{display:flex;gap:25px;justify-content:space-between}.quick-topics div{min-width:0;font-size:13px}.quick-topics strong{margin-right:8px}.quick-topics a{margin-right:12px;white-space:nowrap}.topic-grid{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:16px}.topic-tile{display:block;border:1px solid var(--line);border-radius:12px;background:#fff;padding:21px;text-decoration:none;transition:transform .2s,border-color .2s}.topic-tile:hover{transform:translateY(-3px);border-color:#79c7dd}.topic-tile strong{display:block;font-size:18px;margin-bottom:9px}.topic-tile span{font-size:14px;color:var(--muted);display:block;line-height:1.65}.feature-grid{display:grid;grid-template-columns:2fr 1fr;gap:22px}.feature-main,.feature-side article,.info-panel,.note-card,.content-card{padding:26px;border-radius:14px;background:white;border:1px solid var(--line)}.feature-main h3{font-size:23px}.feature-side{display:grid;gap:20px}.inline-link{font-weight:700;text-decoration:none;border-bottom:1px solid currentColor}.split{display:grid;grid-template-columns:1fr 1fr;gap:44px;align-items:center}.split.reverse .split-media{order:-1}.split p{max-width:590px}.three-cols{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:18px}.step-grid{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:18px;counter-reset:step}.step{background:white;border-top:3px solid var(--cyan);padding:21px 20px;border-radius:0 0 12px 12px}.step b{display:block;color:#138cb0;font-size:13px;margin-bottom:8px}.mini-label{font-size:13px;font-weight:700;color:#0b7c99;margin-bottom:9px}.editor-note{font-size:14px;color:#546d7e;border-left:3px solid var(--sky);padding:16px 22px;background:#fff}.media{display:flex;align-items:center;justify-content:center;width:100%;min-width:0;overflow:hidden;background:var(--light);border-radius:14px}.media img{display:block;width:auto;height:auto;max-width:100%;max-height:100%;object-fit:contain;object-position:center}.media--hero{height:clamp(250px,26vw,330px)}.media--feature{height:250px}.media--card{height:170px}.media--banner{height:220px}.media--mobile{height:350px;max-width:320px;margin-inline:auto}.media--logo{height:38px;max-width:190px;background:transparent;border-radius:0;justify-content:flex-start}.media--wide img{max-height:100%}.media--tall{max-width:420px;margin-inline:auto}.media-placeholder{display:block;width:58%;height:45%;border-radius:15px;background:linear-gradient(120deg,rgba(37,182,232,.08),rgba(37,200,209,.2));border:1px solid rgba(23,135,219,.14)}.media--logo .media-placeholder{display:none}.article-layout{display:grid;grid-template-columns:minmax(0,760px) minmax(0,240px);gap:48px;align-items:start}.article-body{min-width:0}.article-body section{margin-bottom:38px}.article-body h2,.content-block h2{margin:0 0 15px}.article-body p{line-height:1.85}.aside-box{background:var(--light);padding:22px;border-radius:12px;position:sticky;top:20px}.aside-box h2{font-size:19px}.aside-box a{display:block;margin:10px 0}.article-list{padding-left:24px}.article-list li{margin-bottom:9px}.timeline{display:grid;grid-template-columns:repeat(3,1fr);gap:17px}.timeline article{background:#fff;border:1px solid var(--line);border-top:4px solid var(--sky);padding:22px;border-radius:9px}.table-scroll{overflow-x:auto;max-width:100%;border:1px solid var(--line);border-radius:12px;background:#fff;margin:22px 0}.data-table{border-collapse:collapse;width:100%;min-width:590px;font-size:15px}.data-table th,.data-table td{padding:14px 17px;text-align:left;border-bottom:1px solid var(--line);vertical-align:top}.data-table th{background:#e9f5f9;color:var(--title);font-weight:700}.data-table tr:last-child td{border-bottom:0}.read-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:18px}.read-grid article{background:white;border:1px solid var(--line);padding:22px;border-radius:12px}.tag{display:inline-block;padding:4px 10px;background:#dff4f8;color:#126887;border-radius:5px;font-size:12px;font-weight:800;margin-bottom:12px}.rule-nav{display:flex;gap:11px;flex-wrap:wrap;padding:20px;background:white;border:1px solid var(--line);border-radius:12px;margin:0 0 35px}.rule-nav a{padding:7px 14px;background:var(--light);border-radius:7px;text-decoration:none;font-weight:700}.gallery{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:24px}.gallery figure{margin:0;padding:18px;background:#fff;border:1px solid var(--line);border-radius:13px}.gallery figcaption{font-size:14px;color:var(--muted);padding:12px 3px 0}.related{border-top:1px solid var(--line);padding:32px 0 50px;margin-top:28px}.related h2{font-size:22px}.related-links{display:grid;grid-template-columns:repeat(3,1fr);gap:14px}.related-links a{background:white;text-decoration:none;border:1px solid var(--line);border-radius:9px;padding:16px;font-weight:700;display:flex;justify-content:space-between;gap:10px}.faq-list{display:grid;gap:9px}.faq-list details{background:white;border:1px solid var(--line);border-radius:9px}.faq-list summary{cursor:pointer;font-weight:700;color:var(--title);padding:15px 20px}.faq-list details[open] summary{border-bottom:1px solid var(--line)}.faq-list details p{padding:15px 20px;margin:0}.site-footer{background:var(--footer);color:#eaf7ff;padding:45px 0 24px}.footer-layout{display:grid;grid-template-columns:1.35fr 1fr;gap:80px}.site-footer strong,.site-footer h2{color:white}.footer-brand{display:block;font-size:22px;line-height:1.2}.footer-brand small{color:#93dce7}.site-footer p{margin-top:13px;max-width:560px}.site-footer .small{color:#b3cbd9}.footer-links{display:grid;grid-template-columns:repeat(2,1fr);gap:8px}.footer-links a,.footnote a{color:#eaf7ff}.site-footer h2{font-size:17px}.footnote{border-top:1px solid rgba(255,255,255,.19);margin-top:32px;padding-top:16px;display:flex;justify-content:space-between;gap:15px;font-size:13px;color:#c3d5df}.to-top{position:fixed;bottom:25px;right:24px;border:0;background:var(--navy);color:white;width:44px;height:44px;border-radius:10px;opacity:0;pointer-events:none;transition:opacity .2s;z-index:12}.to-top.visible{opacity:1;pointer-events:auto}
@media(max-width:980px){.desktop-nav,.topbar-subtitle{display:none}.topbar{height:64px;justify-content:space-between}.menu-toggle{display:block}.brand{min-width:0;justify-content:center;margin-inline:auto}.media--logo{height:30px;max-width:140px}.brand-fallback{font-size:20px}.brand-fallback small{font-size:8px}.entry-button{height:40px;min-height:40px;padding:0 13px}.drawer-backdrop{display:block;position:fixed;inset:0;background:rgba(5,31,49,.42);opacity:0;visibility:hidden;pointer-events:none;z-index:30;transition:opacity .2s,visibility .2s}.mobile-drawer{display:block;position:fixed;inset:0 auto 0 0;width:min(86vw,344px);background:#fff;box-shadow:7px 0 25px #071f312c;transform:translateX(-102%);visibility:hidden;pointer-events:none;transition:transform .23s,visibility .23s;z-index:31;overflow-y:auto}.drawer-open .drawer-backdrop{opacity:1;visibility:visible;pointer-events:auto}.drawer-open .mobile-drawer{transform:translateX(0);visibility:visible;pointer-events:auto}.drawer-heading{display:flex;justify-content:space-between;align-items:center;padding:18px 23px;border-bottom:1px solid var(--line)}.drawer-close{border:0;background:#eaf6fa;border-radius:8px;width:40px;height:40px;font-size:28px;color:var(--navy);line-height:1}.mobile-drawer nav{padding:5px 23px 40px}.drawer-group{display:block;padding:20px 0 7px;color:#75909d;font-size:12px;letter-spacing:.06em;font-weight:800}.mobile-drawer nav a{display:block;padding:9px 10px;border-radius:8px;color:var(--body);text-decoration:none}.mobile-drawer nav a.active{background:var(--light);color:var(--navy);font-weight:800}.quick-topics .wrap{flex-wrap:wrap;gap:10px 25px}.topic-grid{grid-template-columns:repeat(2,1fr)}.split{gap:28px}.article-layout{grid-template-columns:minmax(0,1fr) 230px;gap:28px}}
@media(max-width:760px){.wrap{width:calc(100% - 44px)}.section{padding:40px 0}.hero{grid-template-columns:1fr;gap:25px;padding:32px 0}.hero .hero-media{order:-1}.hero p{font-size:16px}.feature-grid,.split,.article-layout,.footer-layout{grid-template-columns:1fr}.split.reverse .split-media{order:0}.feature-side{grid-template-columns:repeat(2,minmax(0,1fr))}.three-cols,.read-grid{grid-template-columns:1fr}.aside-box{position:static}.timeline{grid-template-columns:1fr}.related-links{grid-template-columns:1fr}.mobile-bottom{display:grid;grid-template-columns:repeat(4,1fr);position:fixed;bottom:0;left:0;right:0;background:white;box-shadow:0 -4px 20px #12365316;z-index:15;padding-bottom:env(safe-area-inset-bottom);border-top:1px solid var(--line)}.mobile-bottom a{text-decoration:none;text-align:center;padding:10px 0;color:var(--navy);font-weight:700;font-size:13px}.site-footer{padding-bottom:calc(85px + env(safe-area-inset-bottom))}.to-top{bottom:calc(65px + env(safe-area-inset-bottom))}.gallery{gap:14px}}
@media(max-width:640px){.wrap{width:calc(100% - 32px)}h1{font-size:26px}h2{font-size:21px}.hero h1{font-size:29px}.hero-actions{gap:9px}.btn{flex:1 1 145px;padding:9px 12px}.topic-grid,.gallery,.feature-side{grid-template-columns:1fr}.topic-tile{padding:18px}.feature-main,.feature-side article,.info-panel,.note-card,.content-card{padding:19px}.quick-topics{padding:12px 0}.quick-topics .wrap{display:block}.quick-topics div{padding:3px 0}.quick-topics a{margin-right:8px}.media--hero{height:200px}.media--feature{height:180px}.media--card{height:145px}.media--banner{height:150px}.media--mobile{height:290px;max-width:250px}.page-intro{padding-top:36px}.page-intro p{font-size:16px}.data-table{font-size:14px}.footnote{display:block}.footnote a{display:block;margin-top:10px}.brand-fallback{font-size:17px}.entry-button{font-size:12px;padding:0 10px}.topbar{gap:7px}}
@media(max-height:470px) and (max-width:760px){.mobile-bottom{position:static}.site-footer{padding-bottom:30px}.to-top{bottom:15px}}
@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}*,*::before,*::after{transition:none!important;animation:none!important}}