:root{--bg:#F5FBFF;--card:#fff;--pale:#EAF7FC;--cyan:#25C8D1;--sky:#25B6E8;--blue:#1787DB;--navy:#174B78;--title:#173B60;--text:#2D4359;--muted:#687F93;--border:#DCEBF3;--footer:#123653;--shadow:0 14px 45px rgba(23,75,120,.07)}*{box-sizing:border-box}html{scroll-behavior:smooth;scroll-padding-top:95px}body{margin:0;background:var(--bg);font:16px/1.8 Arial,'PingFang SC','Microsoft YaHei',sans-serif;color:var(--text)}a{color:inherit;text-decoration:none}a:hover{color:var(--blue)}button{font:inherit;cursor:pointer}img{display:block;max-width:100%}.wrap{width:min(1160px,calc(100% - 48px));margin-inline:auto}.site-header{height:72px;background:#fff;border-bottom:1px solid var(--border);position:sticky;top:0;z-index:30;box-shadow:0 2px 15px rgba(23,75,120,.035)}.topbar{height:100%;display:flex;gap:24px;align-items:center;justify-content:space-between}.brand{flex:0 0 auto;min-width:115px}.brand img{width:auto;height:37px;max-width:165px;object-fit:contain}.brand-text{display:block;color:var(--title);font-size:22px;line-height:1.05;font-weight:800;letter-spacing:.03em}.brand-text span{color:var(--sky)}.brand-text small{display:block;font-size:9px;letter-spacing:.2em;margin-top:3px;color:var(--blue)}.desktop-nav{display:flex;justify-content:center;gap:21px;align-items:center;flex:1}.desktop-nav a{font-size:14px;color:var(--navy);white-space:nowrap;font-weight:700;padding:22px 0;border-bottom:3px solid transparent}.desktop-nav a:hover,.desktop-nav a[aria-current]{color:var(--blue);border-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:#fff;font-weight:700;white-space:nowrap;font-size:14px}.main-btn:hover{color:#fff;filter:brightness(.95)}.menu-button{display:none;border:0;background:none;width:42px;height:42px;padding:10px;flex-direction:column;justify-content:space-around}.menu-button span{height:2px;background:var(--title);width:100%;border-radius:3px}.skip{position:absolute;top:-100px;left:15px;z-index:60;background:white;padding:10px}.skip:focus{top:5px}.hero{background:linear-gradient(125deg,#EAF9FF,#F6FCFF 60%,#DDF5FC);padding:54px 0 50px;border-bottom:1px solid var(--border)}.hero-inner{display:grid;grid-template-columns:1.04fr .96fr;align-items:center;gap:48px}.eyebrow{color:var(--blue);font-weight:800;font-size:13px;letter-spacing:.14em;text-transform:uppercase}.hero h1{font-size:40px;line-height:1.35;color:var(--title);margin:12px 0 20px;max-width:590px}.hero p{font-size:17px;max-width:590px}.hero-actions{display:flex;gap:13px;align-items:center;flex-wrap:wrap;margin-top:26px}.outline-btn{border:1px solid #91CCEB;border-radius:999px;padding:7px 21px;font-size:14px;font-weight:700;color:var(--navy)}.media{display:flex;justify-content:center;align-items:center;width:100%;min-height:180px;overflow:hidden;background:var(--pale);border-radius:14px}.media img{display:block;width:auto;height:auto;max-width:100%;max-height:100%;object-fit:contain;object-position:center}.hero-media{height:320px}.wide-media{height:240px}.card-media{height:170px}.portrait-media{height:310px;max-width:400px}.media-empty{height:100%;min-height:160px;width:100%;display:flex;justify-content:center;align-items:center;text-align:center;padding:18px;background:linear-gradient(145deg,#DFF5FB,#EAF7FC);color:var(--navy)}.media-empty span{font-size:13px;letter-spacing:.1em;opacity:.7}.section{padding:42px 0}.section-heading{margin-bottom:24px}.section-heading h2,.section h2,.related h2{font-size:26px;line-height:1.4;color:var(--title);margin:0 0 12px}.section-heading p{max-width:750px;margin:0;color:var(--muted)}.topic-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:18px}.topic,.panel,.feature,.note-box,.article-card,.table-wrap{background:#fff;border:1px solid var(--border);border-radius:15px;box-shadow:var(--shadow)}.topic{padding:24px;transition:transform .2s,box-shadow .2s}.topic:hover{transform:translateY(-3px);box-shadow:0 18px 32px rgba(23,75,120,.12)}.topic b{font-size:19px;color:var(--title)}.topic p{margin:7px 0 8px;color:var(--muted);font-size:15px}.topic .arrow{color:var(--blue);font-size:13px;font-weight:700}.split{display:grid;grid-template-columns:1fr 1fr;gap:28px;align-items:center}.panel{padding:28px}.panel h2,.panel h3,.article-card h3{color:var(--title)}.panel h2{margin-top:0}.feature-list{display:grid;grid-template-columns:1fr 1fr;gap:20px}.feature{overflow:hidden}.feature-body{padding:24px}.feature-body h3{font-size:19px;color:var(--title);margin:0 0 10px}.feature-body p{margin:0 0 12px;font-size:15px}.text-link{font-size:14px;color:var(--blue);font-weight:700}.index-list{display:grid;grid-template-columns:repeat(2,1fr);gap:12px}.index-list a{display:block;background:#fff;padding:15px 18px;border:1px solid var(--border);border-radius:10px;font-weight:700;color:var(--navy)}.index-list a:hover{border-color:var(--sky)}.muted-section{background:#EAF7FC}.page-intro{background:linear-gradient(110deg,#E5F7FC,#F5FBFF);padding:48px 0;border-bottom:1px solid var(--border)}.page-intro h1{font-size:34px;line-height:1.38;color:var(--title);margin:10px 0}.page-intro p{max-width:780px;font-size:17px;margin:0}.breadcrumbs{font-size:13px;color:var(--muted)}.breadcrumbs a{color:var(--navy)}.article{max-width:820px;margin:0 auto}.article h2{margin:32px 0 13px;font-size:25px;color:var(--title);line-height:1.4}.article h3{font-size:20px;color:var(--navy);margin:24px 0 8px}.article p{margin:0 0 18px}.article ul,.article ol{padding-left:23px}.article li{padding-bottom:8px}.article blockquote{border-left:4px solid var(--cyan);background:var(--pale);padding:18px 22px;margin:25px 0;color:var(--navy)}.article-wide{max-width:100%}.article-card{padding:26px}.article-card h3{margin-top:0}.compare{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:22px}.mini-label{display:inline-flex;background:var(--pale);color:var(--blue);font-size:12px;font-weight:700;padding:3px 11px;border-radius:30px}.timeline{display:grid;grid-template-columns:1fr 1fr;gap:18px}.timeline .article-card{border-top:4px solid var(--cyan)}.table-wrap{overflow-x:auto;margin:20px 0}table{border-collapse:collapse;width:100%;min-width:560px;background:#fff}th,td{padding:13px 15px;border-bottom:1px solid var(--border);text-align:left;vertical-align:top}th{background:var(--pale);color:var(--title)}.rule-steps{counter-reset:rule;display:grid;grid-template-columns:repeat(3,1fr);gap:16px}.rule-steps>div{background:#fff;border:1px solid var(--border);padding:22px;border-radius:14px}.rule-steps>div:before{counter-increment:rule;content:'0' counter(rule);display:block;color:var(--blue);font-weight:800;font-size:24px}.rule-steps h3{margin:8px 0;color:var(--title)}.rule-steps p{font-size:15px;margin:0}.warning{border-left:4px solid var(--cyan);background:#EAF7FC;border-radius:8px;padding:18px 22px}.gallery-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:20px}.gallery-grid figure{margin:0;background:#fff;padding:12px 12px 20px;border:1px solid var(--border);border-radius:13px}.gallery-grid figcaption{padding:12px 6px 0;font-size:15px}.gallery-grid figcaption b{color:var(--title)}.related{padding:36px 0 52px;border-top:1px solid var(--border)}.related-links{display:flex;gap:12px;flex-wrap:wrap}.related-links a{padding:10px 18px;background:#fff;border-radius:999px;border:1px solid var(--border);color:var(--navy);font-size:14px;font-weight:700}.related-links a:hover{border-color:var(--blue)}.faq{display:grid;gap:12px}.faq details{padding:14px 20px;border:1px solid var(--border);background:#fff;border-radius:11px}.faq summary{font-weight:700;color:var(--title);cursor:pointer}.faq p{margin:8px 0 0}.site-footer{background:var(--footer);color:#EAF7FF;padding:48px 0 18px;margin-top:10px}.footer-grid{display:grid;grid-template-columns:1.2fr 1fr;gap:60px}.footer-name{font-size:23px;font-weight:800}.footer-name small{font-size:11px;letter-spacing:.1em}.site-footer p{font-size:14px;max-width:520px;color:#C9E0EC}.site-footer .notice{font-size:13px}.site-footer h2{font-size:17px;color:#fff;margin:0 0 15px}.footer-nav{display:grid;grid-template-columns:repeat(3,1fr);gap:8px}.footer-nav a{font-size:14px}.footer-nav a:hover,.footer-bottom a:hover{color:#8FE4FA}.footer-bottom{border-top:1px solid rgba(255,255,255,.15);padding-top:19px;margin-top:32px;display:flex;justify-content:space-between;gap:15px;font-size:13px;color:#C9E0EC}.bottom-nav{display:none}.back-top{position:fixed;right:18px;bottom:23px;width:43px;height:43px;border-radius:50%;border:0;background:var(--blue);color:white;z-index:20;opacity:0;pointer-events:none;transition:opacity .2s}.back-top.visible{opacity:1;pointer-events:auto}.drawer-mask{position:fixed;inset:0;background:rgba(5,25,45,.46);z-index:39;opacity:0;visibility:hidden;pointer-events:none;transition:opacity .2s,visibility .2s}.mobile-drawer{position:fixed;z-index:40;top:0;left:0;bottom:0;width:min(86vw,340px);background:white;padding:22px;overflow-y:auto;transform:translateX(-105%);visibility:hidden;transition:transform .25s,visibility .25s;box-shadow:10px 0 28px rgba(0,0,0,.12)}body.drawer-open{overflow:hidden}body.drawer-open .drawer-mask{opacity:1;visibility:visible;pointer-events:auto}body.drawer-open .mobile-drawer{visibility:visible;transform:translateX(0)}.drawer-head{display:flex;justify-content:space-between;align-items:center;color:var(--title);border-bottom:1px solid var(--border);padding-bottom:10px}.drawer-head button{border:0;background:none;color:var(--title);font-size:30px}.drawer-group{padding:14px 0;border-bottom:1px solid var(--border)}.drawer-label{color:var(--muted);font-size:12px;font-weight:700;padding:0 0 6px}.drawer-group a{display:block;color:var(--navy);padding:7px 5px;font-weight:700}.drawer-group a[aria-current]{color:var(--blue)}@media(max-width:1100px){.desktop-nav{gap:11px}.desktop-nav a{font-size:13px}}@media(max-width:980px){.menu-button{display:flex}.desktop-nav{display:none}.topbar{display:grid;grid-template-columns:1fr auto 1fr;gap:10px}.brand{justify-self:center;min-width:0}.enter{justify-self:end}.hero-inner{gap:26px}.hero h1{font-size:34px}}@media(max-width:700px){body{font-size:15px;line-height:1.75;padding-bottom:60px}.wrap{width:calc(100% - 32px)}.site-header{height:60px}.brand img{height:29px;max-width:120px}.brand-text{font-size:18px}.brand-text small{font-size:7px}.enter{height:38px;padding:0 14px;min-width:0;font-size:12px}.menu-button{width:40px;height:40px}.hero{padding:24px 0 34px}.hero-inner,.split{grid-template-columns:1fr}.hero-inner .hero-media{order:-1;height:210px}.hero h1{font-size:29px}.hero p,.page-intro p{font-size:15px}.hero-actions{margin-top:18px}.section{padding:28px 0}.section h2,.section-heading h2,.related h2{font-size:22px}.topic-grid,.feature-list,.compare,.timeline,.gallery-grid,.rule-steps,.footer-grid,.index-list{grid-template-columns:1fr}.topic{padding:20px}.page-intro{padding:32px 0}.page-intro h1{font-size:27px}.article h2{font-size:22px}.article h3{font-size:18px}.panel,.article-card{padding:21px}.hero-media{height:210px}.wide-media{height:175px}.card-media{height:158px}.portrait-media{height:260px}.gallery-grid{grid-template-columns:repeat(2,1fr);gap:12px}.gallery-grid figcaption{font-size:13px}.footer-grid{gap:18px}.footer-nav{grid-template-columns:1fr 1fr}.footer-bottom{flex-direction:column}.bottom-nav{display:flex;position:fixed;bottom:0;left:0;right:0;height:60px;background:white;border-top:1px solid var(--border);z-index:25;justify-content:space-around;align-items:center;box-shadow:0 -2px 12px rgba(23,75,120,.05)}.bottom-nav a{flex:1;text-align:center;font-size:13px;font-weight:700;color:var(--navy)}.bottom-nav a[aria-current]{color:var(--blue)}.back-top{bottom:72px}.site-footer{padding:30px 0 22px}.related{padding:26px 0 38px}}@media(max-width:370px){.brand-text{font-size:16px}.enter{font-size:11px;padding:0 11px}.gallery-grid{grid-template-columns:1fr}}