@charset "UTF-8";
:root{--bg:#f6fafc;--surface:#fff;--soft:#eaf6fa;--soft2:#edf4f8;--cyan:#25c8d1;--sky:#25b6e8;--blue:#1787db;--navy:#174b78;--title:#183a56;--text:#31485d;--muted:#687d8e;--line:#dce9f0;--footer:#123653;--radius:16px}
*{box-sizing:border-box}html{scroll-behavior:smooth;scroll-padding-top:30px}body{margin:0;background:var(--bg);color:var(--text);font:16px/1.8 Arial,"PingFang SC","Microsoft YaHei",sans-serif;overflow-x:hidden}body.drawer-open{overflow:hidden}a{color:var(--navy);text-decoration-color:var(--sky);text-underline-offset:4px}a:hover{color:#087db4}button{font:inherit}button,a,summary{outline-offset:4px}a:focus-visible,button:focus-visible,summary:focus-visible{outline:3px solid #1787db}img{display:block;max-width:100%;height:auto}h1,h2,h3{color:var(--title);line-height:1.38;letter-spacing:-.025em}h1{font-size:clamp(32px,3vw,40px);margin:12px 0 22px}h2{font-size:26px;margin:0 0 18px}h3{font-size:20px;margin:0 0 12px}p{margin:0 0 17px}ul,ol{padding-left:1.4em}li{margin:5px 0}.container{width:min(1180px,calc(100% - 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var(--cyan);border-radius:10px}.knowledge-card .card-num{color:#078ca4;font-weight:800;font-size:13px;letter-spacing:.1em}.reading-steps{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:15px;counter-reset:step}.reading-steps div{border-top:2px solid #25b6e8;padding:18px 8px 0;counter-increment:step}.reading-steps div:before{content:"0" counter(step);display:block;font-size:22px;font-weight:bold;color:#1689a8}.reading-steps strong{display:block;color:var(--title)}.reading-steps p{font-size:14px}.editor-note{border-left:4px solid var(--cyan);background:var(--soft);padding:21px 26px;margin-top:45px;border-radius:0 12px 12px 0}.page-intro{padding:12px 0 5px;max-width:900px}.page-intro h1{font-size:35px;margin-top:10px}.page-intro>p{max-width:790px;font-size:17px}.article-text{max-width:780px}.content-grid{display:grid;grid-template-columns:minmax(0,1fr) 245px;gap:44px;align-items:start}.section-narrow{max-width:800px}.toc-inline{display:flex;flex-wrap:wrap;gap:9px;margin:22px 0 28px}.toc-inline a{border:1px solid var(--line);background:white;text-decoration:none;border-radius:7px;padding:7px 13px;font-size:14px}.side-panel{padding:22px;background:var(--soft);border-radius:12px;position:sticky;top:16px}.side-panel ul{padding-left:18px}.side-panel li{margin:10px 0}.section-copy{max-width:820px}.article-panel{background:#fff;border:1px solid var(--line);padding:28px;border-radius:14px}.compare-wrap{max-width:100%;overflow-x:auto;background:#fff;border:1px solid var(--line);border-radius:11px}.compare-table{width:100%;border-collapse:collapse;min-width:570px;font-size:15px}.compare-table th,.compare-table td{padding:14px 16px;text-align:left;vertical-align:top;border-bottom:1px solid var(--line)}.compare-table thead th{background:var(--soft);color:var(--title)}.compare-table tbody th{white-space:nowrap;color:var(--navy);font-weight:700}.compare-table 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@media(max-width:1100px){.index-grid{grid-template-columns:repeat(3,minmax(0,1fr))}.topic-card:last-child{grid-column:auto}.desktop-nav a{padding:9px 7px;font-size:13px}}
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@media(max-width:520px){.index-grid,.three-column,.matrix,.related-grid{grid-template-columns:1fr}.topic-card:last-child{grid-column:auto}.entry-btn{padding:7px 9px;gap:3px}.toolbar{gap:8px}.brand img{max-width:145px}.brand-fallback{font-size:16px}.brand-fallback small{font-size:7px}.hero-actions .btn{flex:1 1 135px;font-size:13px;padding:10px}.feature-story,.story-stack article,.knowledge-card,.article-panel{padding:19px}.shortcut-grid>div{gap:6px 11px;font-size:12px}.footer-top nav{gap:8px 14px}}
@media(max-height:480px) and (max-width:980px){.bottom-nav{position:static}.site-footer{padding-bottom:0}.back-top{bottom:18px}}
@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}*,*:before,*:after{transition:none!important;animation:none!important}}