body{margin:0;color:var(--ink);background:var(--paper);font-family:-apple-system,BlinkMacSystemFont,"SF Pro Text","SF Pro Display","Helvetica Neue","PingFang SC","Hiragino Sans GB","Microsoft YaHei",Arial,sans-serif;line-height:1.72;text-rendering:optimizeLegibility}
    a{color:var(--blue);text-decoration-thickness:.08em;text-underline-offset:.18em}
    a:hover{text-decoration-thickness:.12em}
    a:focus-visible,button:focus-visible,summary:focus-visible{outline:3px solid rgba(23,105,224,.35);outline-offset:3px;border-radius:3px}
    .progress{position:fixed;z-index:100;inset:0 0 auto;height:3px;background:transparent}
    .progress>span{display:block;height:100%;width:0;background:var(--blue)}
    .topbar{position:sticky;top:0;z-index:90;background:rgba(255,255,255,.92);backdrop-filter:saturate(180%) blur(18px);border-bottom:1px solid rgba(0,0,0,.08)}
    .topbar-inner{max-width:var(--max);margin:auto;height:52px;padding:0 24px;display:flex;align-items:center;justify-content:space-between;gap:16px}