:root{--blue:#3E6AE1;--blue-dark:#2f56c0;--ink:#171A20;--graphite:#393C41;--pewter:#5C5E62;--silver:#8E8E8E;--cloud:#EEEEEE;--pale:#D0D1D2;--ash:#F4F4F4;--white:#FFFFFF;--ok:#15803d;--warn:#b45309;--bad:#b91c1c;--font:-apple-system,"Segoe UI",system-ui,"Helvetica Neue",Arial,"PingFang SC","Microsoft YaHei",sans-serif}*{box-sizing:border-box}html,body{margin:0}body{font-family:var(--font);color:var(--graphite);background:var(--white);-webkit-font-smoothing:antialiased;line-height:1.5}a{color:inherit;text-decoration:none;cursor:pointer}h1,h2,h3{color:var(--ink);font-weight:500;margin:0;letter-spacing:normal}button{font-family:var(--font);cursor:pointer}.nav{position:sticky;top:0;z-index:50;display:flex;align-items:center;gap:28px;padding:0 28px;height:56px;background:#ffffffd9;-webkit-backdrop-filter:blur(10px);backdrop-filter:blur(10px);border-bottom:1px solid var(--cloud)}.nav .brand{font-size:15px;font-weight:600;letter-spacing:.22em;color:var(--ink)}.nav 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