:root{--bg:#F4F7FA;--white:#fff;--light:#EAF1F6;--mint:#E9F8F8;--nav:#102E46;--deep:#163C57;--aqua:#13B8C5;--blue:#237BD3;--head:#18364B;--body:#344C60;--muted:#64798A;--line:#DCE6ED;--foot:#0B2539;--radius:14px}*{box-sizing:border-box}html{scroll-behavior:smooth;scroll-padding-top:24px}body{margin:0;background:var(--bg);color:var(--body);font:16px/1.8 Arial,"PingFang SC","Microsoft YaHei",sans-serif;overflow-x:hidden}a{color:#1265A7;text-decoration:none}a:hover{text-decoration:underline}a:focus-visible,button:focus-visible,summary:focus-visible{outline:3px solid var(--aqua);outline-offset:3px}button{font:inherit;cursor:pointer}img{max-width:100%}.shell{width:min(100% - 56px,1200px);margin-inline:auto}.reading{max-width:800px}.section{margin-block:64px}.section h2,.article-body h2{font-size:27px;line-height:1.4;color:var(--head);margin:0 0 19px}.section h3,.article-body h3{font-size:20px;line-height:1.4;color:var(--head);margin:24px 0 10px}p{margin:0 0 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