:root{--bg:#f5fbff;--surface:#fff;--soft:#eaf7fc;--pale:#dff5fb;--teal:#25c8d1;--sky:#25b6e8;--blue:#1787db;--navy:#174b78;--title:#173b60;--text:#2d4359;--muted:#687f93;--line:#dcebf3;--footer:#123653;--shadow:0 14px 36px rgba(23,75,120,.075)}
*{box-sizing:border-box}html{scroll-behavior:smooth;scroll-padding-top:85px}body{margin:0;background:var(--bg);font-family:Arial,"PingFang SC","Microsoft YaHei",sans-serif;color:var(--text);font-size:16px;line-height:1.8;overflow-x:hidden}a{color:var(--blue);text-decoration:none}a:hover{text-decoration:underline}button{font:inherit;cursor:pointer}img{max-width:100%;height:auto}h1,h2,h3,h4{color:var(--title);line-height:1.38;margin:0 0 18px;font-weight:800}h1{font-size:34px;letter-spacing:-.035em}h2{font-size:25px}h3{font-size:19px}p{margin:0 0 18px}ul,ol{padding-left:1.4em;margin:0 0 20px}li+li{margin-top:8px}strong{color:var(--title)}.container{width:min(1160px,calc(100% - 48px));margin-inline:auto}.article-width{max-width:820px}.eyebrow{display:inline-flex;align-items:center;gap:9px;color:var(--blue);letter-spacing:.12em;font-size:12px;font-weight:800;text-transform:uppercase;margin-bottom:12px}.eyebrow:before{content:'';height:7px;width:7px;background:var(--teal);border-radius:99px}.muted{color:var(--muted)}.lead{font-size:18px;color:#4b6378;line-height:1.82;max-width:820px}.site-header{position:sticky;top:0;background:rgba(255,255,255,.97);border-bottom:1px solid var(--line);z-index:30;backdrop-filter:blur(12px)}.header-inner{min-height:72px;display:flex;align-items:center;gap:22px}.brand{display:flex;align-items:center;justify-content:center;min-width:145px;flex-shrink:0}.brand img{width:auto;height:37px;max-width:162px;object-fit:contain}.brand-fallback{display:flex;flex-direction:column;line-height:1.12;color:var(--blue)}.brand-fallback strong{font-size:23px;color:var(--blue)}.brand-fallback 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img{display:block;width:auto;height:auto;max-width:100%;max-height:100%;object-fit:contain;object-position:center}.media--empty{background:linear-gradient(145deg,#e1f6fb,#f0f9ff);border:1px solid #d4e9f3}.media-shape{width:55%;aspect-ratio:1;border:2px solid rgba(37,182,232,.24);border-radius:26%;transform:rotate(30deg);background:radial-gradient(circle at 35% 35%,rgba(37,200,209,.2),transparent 55%)}.hero-media{height:325px}.feature-media{height:235px}.card-media{height:165px}.portrait-media{height:340px;max-width:350px}.wide-media{height:250px}.section{padding:38px 0}.section-head{display:flex;align-items:end;justify-content:space-between;gap:20px;margin-bottom:22px}.section-head p{margin:0}.section-head h2{margin:0 0 6px}.surface{background:white;border:1px solid var(--line);border-radius:18px;box-shadow:var(--shadow)}.topic-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:16px}.topic-card{background:#fff;border:1px solid var(--line);border-radius:16px;padding:25px 25px 22px;display:block;transition:transform .2s,box-shadow .2s}.topic-card:hover{transform:translateY(-3px);box-shadow:var(--shadow);text-decoration:none}.topic-number{font-size:12px;letter-spacing:.15em;color:var(--sky);font-weight:800}.topic-card h3{margin:9px 0}.topic-card p{color:var(--muted);font-size:14px;margin:0}.topic-arrow{color:var(--blue);font-size:13px;font-weight:800;display:inline-block;margin-top:16px}.split{display:grid;grid-template-columns:1fr 1fr;gap:34px;align-items:center}.editor-panel{border-radius:18px;background:linear-gradient(135deg,#e7f9fa,#f9fcff);padding:30px;border:1px solid var(--line)}.editor-panel h2{margin-bottom:14px}.editor-panel p:last-child{margin-bottom:0}.story-list{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:16px}.story{background:#fff;padding:24px;border:1px solid var(--line);border-radius:16px}.story .tag{color:var(--blue);font-size:12px;font-weight:800}.story h3{margin:8px 0}.story p{font-size:14px;color:var(--muted);margin-bottom:12px}.story a{font-weight:700;font-size:14px}.banner{padding:30px 32px;border-radius:18px;background:linear-gradient(112deg,#174b78,#1787db);color:#fff}.banner h2,.banner p{color:#fff}.banner a{color:#fff;text-decoration:underline}.page-heading{padding:17px 0 27px;border-bottom:1px solid var(--line);margin-bottom:35px}.page-heading .lead{margin-bottom:0}.page-heading h1{max-width:800px}.article-flow section{margin:0 0 39px}.article-flow h2{border-left:4px solid var(--teal);padding-left:15px}.article-flow h3{margin-top:23px}.article-flow blockquote{margin:22px 0;padding:18px 22px;background:var(--soft);border-left:3px solid var(--sky);color:var(--navy)}.reading-layout{display:grid;grid-template-columns:minmax(0,820px) minmax(210px,1fr);gap:38px;align-items:start}.side-index{position:sticky;top:95px;padding:24px;border:1px solid var(--line);background:white;border-radius:16px}.side-index strong{display:block;margin-bottom:12px}.side-index a{display:block;padding:8px 0;color:var(--navy);font-size:14px;border-bottom:1px solid var(--line)}.side-index a:last-child{border-bottom:0}.compare-grid{display:grid;grid-template-columns:1fr 1fr;gap:17px;margin:24px 0}.compare-card{background:var(--surface);border:1px solid var(--line);border-radius:15px;padding:24px}.compare-card h3{margin:0 0 12px}.fact-strip{display:grid;grid-template-columns:repeat(3,1fr);gap:12px;margin:22px 0}.fact-strip>div{padding:19px;border-top:3px solid var(--teal);background:#fff;border-radius:8px;border:1px solid var(--line)}.fact-strip strong{display:block}.fact-strip span{color:var(--muted);font-size:13px}.note{background:#eaf7fc;border:1px solid #d4e9f3;border-radius:14px;padding:22px 25px;margin:22px 0}.note strong{display:block;margin-bottom:8px}.article-photo{margin:25px 0}.article-photo .media{height:240px}.article-photo 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@media(max-width:1100px){.desktop-nav{gap:10px}.desktop-nav a{font-size:13px}.brand{min-width:125px}.header-inner{gap:12px}}
@media(max-width:980px){.desktop-nav{display:none}.menu-toggle{display:flex}.header-inner{justify-content:space-between;height:60px;min-height:60px}.brand{position:absolute;left:50%;transform:translateX(-50%);min-width:0}.brand img{height:29px;max-width:138px}.brand-fallback strong{font-size:18px}.brand-fallback small{font-size:8px}.header-entry{margin-left:auto;height:40px;padding:0 15px;min-width:74px;font-size:13px}.mobile-drawer{display:block;position:fixed;z-index:51;top:0;bottom:0;left:0;width:min(86vw,340px);background:#fff;transform:translateX(-105%);transition:transform .22s ease;overflow-y:auto;overscroll-behavior:contain;padding:20px;box-shadow:12px 0 40px rgba(0,0,0,.12)}.mobile-drawer.is-open{transform:translateX(0)}.menu-backdrop{position:fixed;inset:0;background:rgba(9,32,49,.47);z-index:50;display:block}.menu-backdrop[hidden]{display:none!important}.nav-locked{overflow:hidden}.drawer-heading{display:flex;align-items:center;justify-content:space-between;color:var(--title);font-size:18px;font-weight:800;padding-bottom:18px;border-bottom:1px solid var(--line)}.menu-close{border:0;background:var(--soft);color:var(--navy);width:36px;height:36px;border-radius:10px;font-size:25px}.drawer-group{display:flex;flex-direction:column;padding:14px 0;border-bottom:1px solid var(--line)}.drawer-group strong{font-size:13px;color:var(--muted);margin-bottom:7px}.drawer-group a{color:var(--title);font-size:15px;padding:7px 2px}.reading-layout{grid-template-columns:1fr}.side-index{position:static;order:-1}.side-index a{display:inline-block;margin-right:15px;border-bottom:0}.footer-grid{gap:20px}}
@media(max-width:700px){body{font-size:15px;line-height:1.78}.container{width:calc(100% - 32px)}h1{font-size:27px}h2{font-size:21px}h3{font-size:18px}.lead{font-size:16px}.page{padding:22px 0 38px}.hero{grid-template-columns:1fr;gap:18px;padding:15px 0 24px}.hero h1{font-size:30px}.hero-media{height:210px;order:-1}.section{padding:24px 0}.section-head{align-items:start;flex-direction:column;gap:5px}.topic-grid{grid-template-columns:1fr 1fr;gap:11px}.topic-card{padding:18px}.topic-card p{font-size:13px}.split,.story-list,.compare-grid,.gallery-grid{grid-template-columns:1fr;gap:15px}.split .media{order:-1}.feature-media{height:175px}.editor-panel{padding:22px}.banner{padding:23px}.page-heading{margin-bottom:25px}.article-flow section{margin-bottom:30px}.fact-strip{grid-template-columns:1fr}.portrait-media{height:250px}.wide-media{height:170px}.footer-grid{grid-template-columns:1fr 1fr;gap:24px}.footer-intro{grid-column:span 2}.footer-bottom{display:block}.footer-bottom span{display:block;margin-bottom:8px}.site-footer{padding-bottom:85px}.bottom-nav{display:grid;grid-template-columns:repeat(4,1fr);position:fixed;bottom:0;left:0;right:0;height:calc(58px + env(safe-area-inset-bottom));padding-bottom:env(safe-area-inset-bottom);background:#fff;border-top:1px solid var(--line);z-index:29}.bottom-nav a{display:flex;align-items:center;justify-content:center;font-size:13px;font-weight:700;color:var(--navy)}.bottom-nav a[aria-current="page"]{color:var(--blue);background:var(--soft)}.back-to-top{bottom:74px;right:15px}.article-photo .media{height:175px}}
@media(max-width:370px){.brand img{max-width:100px}.brand-fallback strong{font-size:15px}.header-entry{min-width:68px;padding:0 10px;font-size:12px}.menu-toggle{width:38px;height:38px}.topic-grid{grid-template-columns:1fr}}@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}*,*:before,*:after{transition:none!important}}