@charset "UTF-8";
:root{--bg:#f5fbff;--white:#fff;--soft:#eaf7fc;--mist:#dff5fb;--teal:#25c8d1;--sky:#25b6e8;--blue:#1787db;--ocean:#174b78;--title:#173b60;--body:#2d4359;--muted:#687f93;--border:#dcebf3;--foot:#123653;--shadow:0 16px 45px rgba(26,87,130,.07)}
*{box-sizing:border-box}html{scroll-behavior:smooth;scroll-padding-top:90px}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}a{color:inherit;text-decoration:none}a:hover{color:var(--blue)}button{font:inherit;cursor:pointer}img{max-width:100%}.wrap{width:min(1160px,calc(100% - 48px));margin-inline:auto}.section{margin-block:44px}.section-heading{margin-bottom:24px}.eyebrow{font-weight:800;letter-spacing:.16em;font-size:12px;color:#128ba5}.section-heading h2{margin:6px 0 0}h1,h2,h3{color:var(--title);line-height:1.38;letter-spacing:-.015em}h1{font-size:36px}h2{font-size:25px}h3{font-size:19px}p{margin:0 0 15px}ul,ol{padding-left:23px}li{margin-bottom:8px}.lede{font-size:17px;color:#456178;max-width:780px}.muted{color:var(--muted)}.site-header{height:72px;background:#fff;border-bottom:1px solid var(--border);position:sticky;top:0;z-index:40}.header-inner{height:100%;display:flex;align-items:center;gap:22px}.brand{display:flex;align-items:center;flex:none}.brand-logo{display:block;max-width:170px;width:auto;height:37px;object-fit:contain}.brand-wordmark{display:inline-flex;align-items:center;gap:10px;font-weight:900;color:var(--ocean);font-size:20px;letter-spacing:.025em;line-height:1.2;white-space:nowrap}.brand-wordmark small{display:block;font-size:9px;letter-spacing:.19em;color:#1787db}.mark-ball{display:grid;place-items:center;border-radius:50%;background:linear-gradient(120deg,var(--teal),var(--blue));color:#fff;width:34px;height:34px}.desktop-nav{display:flex;align-items:center;justify-content:center;gap:22px;flex:1;white-space:nowrap}.desktop-nav a{font-size:14px;font-weight:650;color:var(--ocean);height:72px;display:flex;align-items:center;border-bottom:3px solid transparent;padding-top:3px}.desktop-nav a:hover,.desktop-nav 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.25s}.mobile-drawer{position:fixed;z-index:61;top:0;bottom:0;left:0;background:#fff;width:min(86vw,340px);transform:translateX(-102%);visibility:hidden;pointer-events:none;transition:transform .26s,visibility .26s;box-shadow:12px 0 40px #06243b22;display:flex;flex-direction:column}.drawer-head{display:flex;align-items:center;justify-content:space-between;padding:16px 20px;border-bottom:1px solid var(--border)}.drawer-close{border:0;background:var(--soft);border-radius:50%;width:34px;height:34px;font-size:26px;color:var(--title);line-height:1}.drawer-content{overflow:auto;padding:10px 20px 24px}.drawer-content a{display:block;padding:9px 8px;border-bottom:1px solid var(--border);font-size:15px}.drawer-group{font-size:12px;font-weight:800;color:#158faf;letter-spacing:.12em;margin:20px 0 4px}.drawer-open{overflow:hidden}.drawer-open .drawer-overlay{opacity:1;visibility:visible;pointer-events:auto}.drawer-open .mobile-drawer{transform:translateX(0);visibility:visible;pointer-events:auto}.hero{background:linear-gradient(125deg,#e9f9fd 10%,#fafdff 52%,#ddf4ff 100%);border-bottom:1px solid var(--border)}.hero-inner{display:grid;grid-template-columns:1.08fr .92fr;align-items:center;gap:45px;padding:65px 0}.hero h1{font-size:39px;margin:12px 0 20px}.hero .lede{margin-bottom:25px}.hero-actions{display:flex;gap:12px;flex-wrap:wrap}.outline-btn{display:inline-flex;align-items:center;border:1px solid #acd7eb;border-radius:100px;padding:7px 20px;background:#ffffffbb;color:var(--ocean);font-weight:700}.kicker{font-size:12px;letter-spacing:.22em;color:#0a91b1;font-weight:800}.media{width:100%;min-height:210px;max-height:290px;display:flex;align-items:center;justify-content:center;overflow:hidden;border-radius:15px;background:var(--soft);border:1px solid #d6edf4}.media img{display:block;width:auto;height:auto;max-width:100%;max-height:100%;object-fit:contain;object-position:center}.media.is-placeholder{position:relative;background:linear-gradient(135deg,#c6f2f4,#e8fbff 54%,#c6e7fa)}.media-placeholder{width:72%;height:70%;display:flex;align-items:center;justify-content:center;border:1px solid #ffffffab;border-radius:28px;transform:rotate(-6deg);background:radial-gradient(circle at 40% 32%,#ffffffcc,transparent 42%),linear-gradient(120deg,#25c8d12b,#1787db24)}.placeholder-shape{width:34%;aspect-ratio:1;border:8px solid #ffffff9c;border-radius:50%;box-shadow:0 0 0 20px #ffffff29,0 0 0 43px #ffffff1a}.hero-media{min-height:280px;max-height:330px;box-shadow:var(--shadow)}.panel,.article-card,.fact-box{background:#fff;border:1px solid var(--border);border-radius:18px;box-shadow:var(--shadow)}.panel{padding:28px}.section-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:18px}.topic-card{display:block;padding:25px;border-radius:16px;border:1px solid var(--border);background:#fff;transition:transform .2s,box-shadow .2s}.topic-card:hover{transform:translateY(-3px);box-shadow:var(--shadow)}.topic-card .number{color:#0b99b4;font-weight:850;font-size:13px;letter-spacing:.1em}.topic-card h3{margin:10px 0 9px}.topic-card p{font-size:14px;color:var(--muted);margin:0}.topic-card .arrow{display:block;font-weight:800;color:#159bb8;margin-top:12px}.feature-split{display:grid;grid-template-columns:1fr 1fr;gap:34px;align-items:center}.feature-split.reverse .media{order:2}.feature-copy h2{margin:8px 0 18px}.two-up{display:grid;grid-template-columns:1fr 1fr;gap:18px}.spotlight{padding:27px;border-top:3px solid var(--teal);background:#fff;border-radius:0 0 14px 14px}.spotlight h3{margin:0 0 12px}.article-index{display:grid;grid-template-columns:1fr 1fr;gap:0 36px;border-top:1px solid var(--border)}.article-index a{display:flex;align-items:center;justify-content:space-between;padding:16px 4px;border-bottom:1px solid var(--border);gap:15px;font-weight:700}.article-index em{font-size:12px;font-style:normal;color:#0998b6}.banner{padding:34px;background:linear-gradient(115deg,#14476e,#1674b3 60%,#25b6d7);border-radius:18px;color:#fff}.banner h2,.banner p{color:#fff}.banner h2{margin-top:0}.banner a{display:inline-block;background:#fff;color:var(--ocean);border-radius:100px;padding:7px 19px;font-weight:800}.page-top{padding:48px 0 38px;background:linear-gradient(110deg,#e5f7fd,#f8fcff);border-bottom:1px solid var(--border)}.page-top h1{font-size:33px;margin:8px 0 12px}.page-top p{max-width:820px}.breadcrumbs{font-size:13px;color:var(--muted)}.content-layout{display:grid;grid-template-columns:minmax(0,800px) 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.media{max-height:260px}.mosaic figure{margin:0;background:#fff;padding:12px;border-radius:15px;border:1px solid var(--border)}.mosaic figcaption{padding:12px 7px;font-size:14px;color:var(--muted)}.faq details{border-bottom:1px solid var(--border);background:#fff;padding:14px 19px}.faq details:first-child{border-radius:12px 12px 0 0}.faq details:last-child{border-radius:0 0 12px 12px}.faq summary{font-weight:700;color:var(--title);cursor:pointer}.faq p{padding-top:12px;font-size:15px}.related-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:12px}.related-link{background:#fff;border:1px solid var(--border);border-radius:12px;padding:17px 19px;display:flex;align-items:center;justify-content:space-between;font-weight:750}.related-link span:last-child{color:var(--sky)}.site-footer{background:var(--foot);color:#eaf7ff;margin-top:70px}.footer-grid{display:grid;grid-template-columns:2fr 1fr 1fr;gap:65px;padding:51px 0 34px}.site-footer a{display:block;color:#eaf7ff;font-size:14px;margin-bottom:8px}.site-footer a:hover{color:#8cebf4}.site-footer h2{color:#fff;font-size:16px;margin:0 0 14px}.footer-intro p{font-size:14px;max-width:450px}.footer-small{opacity:.75}.footer-brand{display:inline-block!important;margin-bottom:20px!important}.footer-brand .brand-wordmark{color:#fff}.footer-brand .brand-wordmark small{color:#aaeefa}.footer-bottom{border-top:1px solid #ffffff20;padding:18px 0;display:flex;justify-content:space-between;color:#c4dce9;font-size:12px}.back-top{position:fixed;right:22px;bottom:23px;width:39px;height:39px;border:0;border-radius:50%;color:#fff;background:var(--blue);box-shadow:0 7px 20px #1b639544;opacity:0;pointer-events:none;transition:opacity .2s;z-index:30}.back-top.visible{opacity:1;pointer-events:auto}.bottom-nav{display:none}
@media(max-width:1100px){.desktop-nav{gap:12px}.desktop-nav a{font-size:13px}.brand-logo{max-width:140px}.brand-wordmark{font-size:17px}}
@media(max-width:980px){.site-header{height:60px}.header-inner{justify-content:space-between;gap:8px}.menu-toggle{display:block;flex:none}.desktop-nav{display:none}.brand{position:absolute;left:50%;transform:translateX(-50%)}.brand-logo{height:29px;max-width:143px}.brand-wordmark{font-size:16px}.mark-ball{width:27px;height:27px}.enter-btn{height:40px;padding:0 15px;min-width:78px;font-size:13px;margin-left:auto}.bottom-nav{display:flex;position:fixed;z-index:35;bottom:0;left:0;right:0;background:#fff;border-top:1px solid var(--border);padding-bottom:env(safe-area-inset-bottom);box-shadow:0 -5px 22px #0b4f7910}.bottom-nav a{width:25%;text-align:center;color:#63839b;font-size:20px;font-weight:800;line-height:1.1;padding:8px 0 6px}.bottom-nav a span{display:block;font-size:11px;font-weight:650;margin-top:3px}.bottom-nav a[aria-current="page"]{color:var(--blue)}.site-footer{margin-bottom:59px}.back-top{bottom:85px}.content-layout{grid-template-columns:1fr}.side-note{position:static}.hero-inner{gap:26px;padding:43px 0}}
@media(max-width:690px){body{font-size:15px}.wrap{width:calc(100% - 32px)}.section{margin-block:29px}.section-heading{margin-bottom:17px}h2{font-size:21px}h3{font-size:18px}.hero-inner{display:flex;flex-direction:column;align-items:stretch;padding:27px 0 34px}.hero-media{order:-1;min-height:185px;max-height:230px}.hero h1{font-size:29px}.hero .lede{font-size:15px}.page-top{padding:29px 0 26px}.page-top h1{font-size:27px}.page-top p{font-size:15px}.section-grid,.two-up,.compare-grid,.reading-strip,.mosaic,.article-index,.related-grid{grid-template-columns:1fr}.feature-split{grid-template-columns:1fr;gap:18px}.feature-split.reverse .media{order:0}.panel{padding:19px}.topic-card{padding:20px}.feature-copy h2{margin:3px 0 10px}.content-layout{margin-top:22px}.prose .media{min-height:180px;max-height:220px}.footer-grid{grid-template-columns:1fr 1fr;gap:23px;padding:35px 0 24px}.footer-intro{grid-column:1/-1}.footer-bottom{flex-direction:column;gap:4px}.banner{padding:25px}.article-index{gap:0}}
@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}*,*:before,*:after{transition:none!important}}