:root{--bg:#f6fafc;--white:#fff;--soft:#eaf6fa;--soft2:#edf4f8;--cyan:#25c8d1;--blue:#1787db;--deep:#174b78;--heading:#183a56;--ink:#31485d;--muted:#687d8e;--line:#dce9f0;--radius:16px}*{box-sizing:border-box}html{scroll-behavior:smooth;scroll-padding-top:26px}body{margin:0;background:var(--bg);color:var(--ink);font:16px/1.8 Arial,"PingFang SC","Microsoft YaHei",sans-serif;overflow-x:hidden}body.drawer-open{overflow:hidden}a{color:var(--deep);text-underline-offset:4px}a:hover{color:#086aaf}a:focus-visible,button:focus-visible,summary:focus-visible{outline:3px solid var(--cyan);outline-offset:4px}button{font:inherit;cursor:pointer}.container{width:min(100% - 56px,1180px);margin-inline:auto}.skip-link{position:absolute;z-index:100;top:-100px;left:10px;background:#fff;padding:8px 16px}.skip-link:focus{top:10px}.site-header{background:#fff;border-bottom:1px solid var(--line)}.topbar{height:72px;display:flex;align-items:center;gap:24px}.brand{display:flex;align-items:center;text-decoration:none;min-width:185px}.brand-fallback,.footer-brand{font-size:22px;font-weight:800;letter-spacing:.04em;color:var(--deep);line-height:1.25}.brand-fallback small,.footer-brand small{display:block;font-size:10px;font-weight:700;letter-spacing:.17em;margin-top:5px}.brand .media{background:transparent;border-radius:0;width:auto;max-width:210px}.media--logo{height:38px}.media--logo img{max-height:38px}.brand-tagline{color:var(--muted);font-size:13px;letter-spacing:.08em;margin:auto}.entry-button{display:inline-flex;align-items:center;justify-content:center;gap:12px;min-height:42px;padding:8px 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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}.media--wide.media--feature{height:210px}.media--tall.media--card{height:210px}.media--empty{background:linear-gradient(130deg,#e5f2f6,#d8eef3)}.empty-symbol{width:36%;height:36%;border:2px solid #c8e5ed;border-radius:16px;transform:rotate(-8deg)}.topic-grid{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:15px}.topic-card,.panel{background:#fff;border:1px solid var(--line);border-radius:var(--radius);padding:24px}.topic-card h3{margin-bottom:9px}.topic-card p{font-size:14px;line-height:1.75;color:var(--muted);margin-bottom:12px}.topic-card a,.text-link{font-weight:700;text-decoration-thickness:1px}.topic-card 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@media(max-width:760px){.hero-grid,.feature-row,.split-feature,.footer-layout,.layout-aside{grid-template-columns:minmax(0,1fr)}.hero{padding:33px 0}.hero-grid .hero-visual{order:-1}.feature-row--reverse .feature-visual{order:0}.comparison-grid,.three-columns,.reading-list{grid-template-columns:minmax(0,1fr)}.steps{grid-template-columns:repeat(2,minmax(0,1fr))}.aside-box{position:static}.editorial-gallery{grid-template-columns:1fr 1fr}.site-footer{padding-bottom:82px}.mobile-bottom{display:flex;position:fixed;z-index:25;bottom:0;left:0;right:0;justify-content:space-around;align-items:center;padding:7px 6px calc(7px + env(safe-area-inset-bottom));background:#fff;border-top:1px solid var(--line);box-shadow:0 -3px 16px #12365312}.mobile-bottom a{font-size:13px;text-decoration:none;text-align:center;padding:4px 13px;font-weight:700}.back-top{bottom:89px;right:12px}.page-intro{padding-top:32px}}
@media(max-width:640px){.container{width:calc(100% - 32px)}body{font-size:15px;line-height:1.78}h1{font-size:29px}h2{font-size:22px}h3{font-size:18px}.lead{font-size:16px}.site-section{padding-block:33px}.topic-grid,.editorial-gallery{grid-template-columns:minmax(0,1fr)}.topic-card,.panel{padding:19px}.quickbar-inner{gap:8px 22px}.quickbar-group{flex-wrap:wrap}.media--hero{height:200px}.media--feature,.media--wide.media--feature{height:180px}.media--card,.media--tall.media--card{height:145px}.media--banner{height:150px}.media--mobile{height:290px;max-width:250px}.hero-actions{gap:9px}.button{padding:8px 14px}.steps{gap:9px}.step{padding:12px}.feature-large{padding:22px}.reading-list a{padding:16px}.footer-links{gap:6px}.topbar{gap:8px}.brand{max-width:145px}.entry-button{padding:7px 10px;font-size:12px}}
@media(max-height:500px) and (max-width:760px){.mobile-bottom{position:static}.site-footer{padding-bottom:15px}.back-top{bottom:18px}}
@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}*,*::before,*::after{animation:none!important;transition:none!important}}