:root{--bg:#F4F7FA;--white:#fff;--mist:#EAF1F6;--ice:#E9F8F8;--navy:#102E46;--deep:#163C57;--teal:#13B8C5;--blue:#237BD3;--heading:#18364B;--body:#344C60;--muted:#64798A;--line:#DCE6ED;--max:1200px}*{box-sizing:border-box}html{scroll-behavior:smooth;scroll-padding-top:24px}body{margin:0;background:var(--bg);color:var(--body);font-family:Arial,"PingFang SC","Microsoft YaHei",sans-serif;font-size:16px;line-height:1.82}img{max-width:100%;height:auto}a{color:#1769b5;text-decoration:none}a:hover{text-decoration:underline}a:focus-visible,button:focus-visible,summary:focus-visible{outline:3px solid var(--teal);outline-offset:3px}h1,h2,h3,h4{color:var(--heading);line-height:1.38;margin:0 0 .7em}h1{font-size:clamp(2rem,3vw,2.65rem)}h2{font-size:clamp(1.5rem,2.1vw,1.75rem)}h3{font-size:1.23rem}p{margin:.65em 0 1.15em}ul,ol{padding-left:1.35em}.shell{max-width:var(--max);padding-left:28px;padding-right:28px;margin:0 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