.refs li{padding-left:5px}.footer{border-top:1px solid var(--line);padding:30px 24px 60px;color:var(--muted);font-size:13px;text-align:center}
    @media(max-width:880px){.layout{grid-template-columns:1fr;gap:0}.toc{position:relative;top:auto;max-height:none;border-left:0;border-top:1px solid var(--line);border-bottom:1px solid var(--line);padding:16px 0 12px;display:grid;grid-template-columns:repeat(2,minmax(0,1fr));column-gap:20px}.toc strong{grid-column:1/-1;margin-bottom:5px}.hero{padding-top:72px}.three{grid-template-columns:1fr}.toplinks a:first-child{display:none}}
    @media(max-width:600px){body{font-size:15px}.topbar-inner,.hero,.layout{padding-left:18px;padding-right:18px}.hero{padding-bottom:48px}.hero h1{font-size:44px}.grid{grid-template-columns:1fr}.toc{grid-template-columns:1fr 1fr}.content section{padding:52px 0}.cell{padding:18px}.mathbox{padding:16px}.toplinks{gap:10px}.toplinks a:nth-child(2){display:none}}
    @media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}*{animation-duration:.01ms!important;transition-duration:.01ms!important}}
    @media print{.progress,.topbar,.toc{display:none}.layout{display:block;max-width:900px}.content section{break-inside:auto}.hero{padding-top:40px}a{color:inherit;text-decoration:underline}}
  