:root{--paper:#f5fbff;--white:#fff;--mist:#eaf7fc;--ice:#dff5fb;--cyan:#25c8d1;--sky:#25b6e8;--blue:#1787db;--navy:#174b78;--ink:#173b60;--body:#2d4359;--muted:#687f93;--line:#dcebf3;--footer:#123653;--radius:18px;--shadow:0 14px 40px rgba(19,75,120,.065)}*{box-sizing:border-box}html{scroll-behavior:smooth;scroll-padding-top:88px}body{margin:0;background:var(--paper);color:var(--body);font:16px/1.8 Arial,"PingFang SC","Microsoft YaHei",sans-serif;overflow-x:hidden}a{color:var(--navy);text-decoration:none}a:hover{color:var(--blue)}button{font:inherit;cursor:pointer}img{max-width:100%}.container{width:min(1160px,calc(100% - 48px));margin-inline:auto}.skip{position:absolute;left:-9999px;top:5px;z-index:200}.skip:focus{left:16px;background:white;padding:8px}.site-header{background:white;border-bottom:1px solid var(--line);position:sticky;top:0;z-index:50}.header-inner{height:72px;display:flex;align-items:center;gap:28px}.brand{display:inline-flex;align-items:center;flex:0 0 auto;min-width:0}.brand-img{display:block;height:37px;width:auto;max-width:200px;object-fit:contain}.brand-fallback{font-size:24px;line-height:1.1;font-weight:900;color:var(--navy);letter-spacing:.04em;white-space:nowrap}.brand-fallback span{color:var(--cyan)}.brand-fallback small{display:block;font-size:9px;letter-spacing:.24em;color:var(--muted);margin-top:3px}.desktop-nav{display:flex;align-items:center;justify-content:center;gap:19px;flex:1;white-space:nowrap}.desktop-nav a{font-size:14px;font-weight:700;color:var(--ink);padding:22px 0;border-bottom:3px solid transparent}.desktop-nav a:hover,.desktop-nav a.active{color:var(--blue);border-bottom-color:var(--cyan)}.main-btn{display:inline-flex;align-items:center;justify-content:center;min-width:82px;height:42px;padding:0 20px;border-radius:999px;background:linear-gradient(110deg,#25c8d1,#25b6e8,#1787db);color:white;font-weight:700;text-decoration:none;white-space:nowrap;box-shadow:0 8px 20px rgba(23,135,219,.15)}.main-btn:hover{color:white;filter:brightness(.96);transform:translateY(-1px)}.menu-toggle{display:none;background:none;border:0;padding:8px;width:42px;height:42px;flex-direction:column;justify-content:center;gap:5px}.menu-toggle span{height:2px;background:var(--navy);width:24px;border-radius:4px}.drawer-mask{position:fixed;inset:0;background:rgba(10,30,48,.52);z-index:80;opacity:0;visibility:hidden;pointer-events:none;transition:opacity .2s,visibility .2s}.drawer-mask.open{opacity:1;visibility:visible;pointer-events:auto}.drawer{position:fixed;top:0;left:0;bottom:0;width:min(86vw,340px);background:white;z-index:90;transform:translateX(-105%);visibility:hidden;transition:transform .25s,visibility .25s;box-shadow:10px 0 40px rgba(8,35,60,.15);overflow-y:auto}.drawer.open{transform:translateX(0);visibility:visible}.drawer-head{display:flex;align-items:center;justify-content:space-between;padding:18px 20px;border-bottom:1px solid var(--line)}.drawer-close{border:0;background:var(--mist);border-radius:12px;width:38px;height:38px;font-size:25px;line-height:1}.drawer-body{padding:8px 20px 25px}.drawer-label{font-weight:800;color:var(--blue);font-size:13px;margin:22px 0 7px;letter-spacing:.06em}.drawer-body>a{display:block;padding:9px 10px;border-radius:9px;color:var(--ink);font-weight:600}.drawer-body>a.active,.drawer-body>a:hover{background:var(--mist);color:var(--blue)}body.drawer-open{overflow:hidden}.hero{padding:54px 0 18px}.hero-grid{display:grid;grid-template-columns:1.03fr .97fr;align-items:center;gap:42px}.eyebrow{display:inline-flex;gap:8px;align-items:center;font-size:13px;letter-spacing:.12em;font-weight:800;text-transform:uppercase;color:var(--blue);margin:0 0 10px}.eyebrow::before{content:"";width:22px;height:3px;border-radius:9px;background:var(--cyan)}h1,h2,h3{color:var(--ink);line-height:1.38;margin:0 0 14px}h1{font-size:38px;letter-spacing:-.025em}h2{font-size:25px}h3{font-size:19px}p{margin:0 0 15px} .lead{font-size:17px;line-height:1.85;color:#4a647a;max-width:720px}.hero .lead{max-width:560px}.hero-actions{display:flex;gap:12px;flex-wrap:wrap;margin:24px 0}.outline-btn{display:inline-flex;align-items:center;justify-content:center;padding:8px 19px;border:1px solid #b6dbec;border-radius:999px;font-weight:700;background:white}.hero-stats{display:flex;gap:22px;flex-wrap:wrap;margin-top:22px;font-size:13px;color:var(--muted)}.hero-stats strong{color:var(--navy);display:block;font-size:19px;line-height:1.3}.media{display:flex;justify-content:center;align-items:center;width:100%;min-width:0;overflow:hidden;background:var(--mist);border-radius:14px}.media img{display:block;width:auto;height:auto;max-width:100%;max-height:100%;object-fit:contain;object-position:center}.media.placeholder{position:relative;background:linear-gradient(135deg,#def5fb 0%,#eaf7fc 48%,#d4eafb 100%);border:1px solid #d2eaf4}.placeholder-shape{width:42%;height:42%;border:2px solid rgba(23,135,219,.14);border-radius:40% 60% 60% 40%;transform:rotate(-22deg);box-shadow:35px 10px 0 -15px rgba(37,200,209,.11),-30px -20px 0 -18px rgba(23,135,219,.1)}.hero-media{height:310px;border-radius:24px}.wide-media{height:250px}.card-media{height:175px}.side-media{height:240px}.small-media{height:150px}.mobile-media{height:340px;max-width:275px;margin:auto}.section{padding:34px 0}.section-head{display:flex;justify-content:space-between;align-items:end;gap:20px;margin-bottom:21px}.section-head p{color:var(--muted);margin:0;max-width:670px}.more{font-weight:800;color:var(--blue);font-size:14px;white-space:nowrap}.section-label{font-size:12px;letter-spacing:.12em;color:var(--blue);font-weight:800;text-transform:uppercase;margin-bottom:8px}.card-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:20px}.card{background:var(--white);border:1px solid var(--line);border-radius:var(--radius);padding:23px;min-width:0;box-shadow:var(--shadow)}.card p:last-child{margin-bottom:0}.card .kicker{font-size:12px;color:var(--blue);font-weight:800;letter-spacing:.07em}.card h3 a{color:inherit}.card h3 a:hover{color:var(--blue)}.card.media-card{padding:12px}.media-card .card-body{padding:15px 10px 11px}.card-link{font-size:14px;font-weight:800;color:var(--blue)}.feature-split{display:grid;grid-template-columns:1fr 1fr;gap:32px;align-items:center;background:var(--white);border:1px solid var(--line);border-radius:23px;padding:28px;box-shadow:var(--shadow)}.feature-split.reverse .media{order:2}.feature-split.reverse>div:last-child{order:1}.feature-split ul{padding-left:20px}.index-list{display:grid;grid-template-columns:repeat(2,1fr);gap:14px}.index-item{display:flex;justify-content:space-between;align-items:center;gap:15px;background:white;border:1px solid var(--line);border-radius:13px;padding:15px 19px}.index-item strong{display:block;font-size:17px;color:var(--ink)}.index-item span{font-size:13px;color:var(--muted)}.index-item:after{content:'↗';color:var(--blue);font-size:19px}.page-hero{padding:42px 0 25px;background:linear-gradient(125deg,#e8f8fc,#f5fbff 70%);border-bottom:1px solid var(--line)}.page-hero .lead{margin-bottom:0}.crumb{display:flex;gap:10px;font-size:13px;color:var(--muted);margin-bottom:17px}.crumb a{color:var(--blue)}.article-layout{display:grid;grid-template-columns:minmax(0,800px) minmax(220px,1fr);gap:32px;align-items:start}.article{min-width:0}.article>section{margin:0 0 36px}.article h2{padding-top:4px}.article h3{margin-top:20px}.article p{line-height:1.85}.toc{position:sticky;top:100px;background:white;border:1px solid var(--line);border-radius:16px;padding:22px}.toc h2{font-size:17px}.toc a{display:block;padding:7px 0;font-size:14px;border-bottom:1px solid var(--line)}.toc a:last-child{border:0}.callout{padding:21px 24px;background:var(--mist);border-left:4px solid var(--cyan);border-radius:0 13px 13px 0;margin:23px 0}.callout strong{display:block;color:var(--ink);margin-bottom:7px}.compare{display:grid;grid-template-columns:1fr 1fr;gap:18px;margin:22px 0}.compare>div{padding:22px;background:white;border:1px solid var(--line);border-radius:14px}.compare h3{margin-top:0}.readable-table{width:100%;border-collapse:collapse;margin:19px 0 25px;font-size:15px;background:white}.readable-table th,.readable-table td{text-align:left;vertical-align:top;border:1px solid var(--line);padding:12px 15px}.readable-table th{background:var(--mist);color:var(--ink)}.step-list{counter-reset:steps;padding:0;list-style:none}.step-list li{position:relative;padding:0 0 20px 51px;margin-bottom:15px;border-bottom:1px solid var(--line)}.step-list li:before{counter-increment:steps;content:counter(steps);position:absolute;top:2px;left:0;width:34px;height:34px;border-radius:50%;background:var(--ice);color:var(--blue);display:grid;place-items:center;font-weight:800}.quote{font-size:21px;line-height:1.7;color:var(--navy);padding:16px 25px;border-left:4px solid var(--blue);margin:22px 0}.tagline{display:flex;gap:10px;flex-wrap:wrap;margin:20px 0}.tagline span{font-size:13px;color:var(--navy);background:var(--ice);padding:4px 13px;border-radius:99px}.related{border-top:1px solid var(--line);padding-top:24px;margin-top:36px}.related-links{display:flex;gap:11px;flex-wrap:wrap}.related-link{padding:9px 15px;border:1px solid #c7e4ee;border-radius:999px;background:white;font-weight:700;font-size:14px}.topic-grid{display:grid;grid-template-columns:1fr 1fr;gap:18px}.topic{padding:23px;background:white;border:1px solid var(--line);border-radius:15px}.topic .number{font-size:13px;color:var(--blue);font-weight:800}.faq details{background:white;border:1px solid var(--line);border-radius:11px;margin:0 0 10px;padding:14px 19px}.faq summary{font-weight:800;color:var(--ink);cursor:pointer}.faq details p{padding-top:11px;margin:0}.site-footer{background:var(--footer);color:#d8ecf9;margin-top:50px;padding:39px 0 20px}.footer-top{display:grid;grid-template-columns:1fr 1fr;gap:60px}.footer-top p{font-size:14px;max-width:430px;margin-top:16px}.footer-brand .brand-fallback{color:white}.footer-brand .brand-fallback small{color:#a9cfdf}.footer-top h2{font-size:17px;color:white}.footer-links{display:flex;gap:12px 22px;flex-wrap:wrap}.footer-links a{font-size:14px;color:#d8ecf9}.footer-links a:hover{color:white;text-decoration:underline}.footer-bottom{border-top:1px solid rgba(255,255,255,.16);margin-top:25px;padding-top:16px;font-size:12px;color:#b5d3e5;display:flex;justify-content:space-between;gap:20px}.bottom-nav{display:none}.to-top{position:fixed;right:20px;bottom:24px;width:44px;height:44px;border:0;border-radius:50%;background:var(--blue);color:white;box-shadow:0 10px 25px rgba(23,135,219,.2);opacity:0;visibility:hidden;transition:opacity .2s;z-index:20}.to-top.visible{opacity:1;visibility:visible}a:focus-visible,button:focus-visible,summary:focus-visible{outline:3px solid var(--cyan);outline-offset:3px}@media(max-width:1100px){.desktop-nav{gap:11px}.desktop-nav a{font-size:13px}.header-inner{gap:16px}.brand-img{max-width:160px}}@media(max-width:980px){.desktop-nav{display:none}.menu-toggle{display:flex}.header-inner{height:60px;justify-content:space-between;gap:12px}.header-inner .brand{position:absolute;left:50%;transform:translateX(-50%);max-width:42%}.brand-img{height:29px;max-width:100%}.brand-fallback{font-size:19px}.header-cta{height:38px;padding:0 13px;font-size:13px;margin-left:auto}.hero-grid{gap:22px}.article-layout{grid-template-columns:minmax(0,1fr)}.toc{position:static;order:-1}.article-layout .toc{display:none}}@media(max-width:700px){.container{width:calc(100% - 32px)}body{font-size:15px;line-height:1.78}h1{font-size:29px}h2{font-size:21px}h3{font-size:18px}.lead{font-size:15.5px}.hero{padding:26px 0 8px}.hero-grid{grid-template-columns:1fr;gap:16px}.hero-grid>.media{order:-1}.hero-media{height:205px}.hero-actions{margin:17px 0}.hero-stats{gap:20px}.section{padding:25px 0}.section-head{display:block}.section-head .more{display:inline-block;margin-top:8px}.card-grid{grid-template-columns:1fr;gap:13px}.card{padding:19px}.feature-split{grid-template-columns:1fr;padding:17px;gap:17px}.feature-split.reverse .media,.feature-split.reverse>div:last-child{order:initial}.wide-media,.side-media{height:175px}.card-media{height:156px}.index-list,.topic-grid,.compare{grid-template-columns:1fr}.page-hero{padding:23px 0}.article>section{margin-bottom:26px}.readable-table{font-size:13px}.readable-table td,.readable-table th{padding:9px}.footer-top{grid-template-columns:1fr;gap:18px}.footer-bottom{flex-direction:column;gap:5px}.site-footer{padding-bottom:90px}.bottom-nav{display:flex;position:fixed;bottom:0;left:0;right:0;background:white;border-top:1px solid var(--line);z-index:45;padding:6px max(12px,env(safe-area-inset-right)) calc(6px + env(safe-area-inset-bottom));justify-content:space-around}.bottom-nav a{font-size:12px;color:var(--navy);font-weight:800;padding:6px 12px}.bottom-nav a[aria-current]{color:var(--blue)}.to-top{bottom:84px;right:13px;width:39px;height:39px}.mobile-media{height:280px}.header-inner .brand{max-width:39%}}@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}*,*:before,*:after{transition:none!important;animation:none!important}}
