:root{--paper:#F6F7F9;--sheet:#fff;--ink:#17202A;--muted:#5A6472;--line:#D5DAE1;--blue:#1D46A8;
  --serif:Charter,"Bitstream Charter","Sitka Text",Cambria,Georgia,serif;--sans:system-ui,-apple-system,"Segoe UI",Roboto,Arial,sans-serif}
@media (prefers-color-scheme: dark){:root{--paper:#11151C;--sheet:#181E27;--ink:#E7ECF3;--muted:#9AA6B6;--line:#2B3442;--blue:#86A6FF}}
*{box-sizing:border-box}
:root{padding-top:env(safe-area-inset-top,0px);padding-bottom:env(safe-area-inset-bottom,0px)}
body{margin:0;background:var(--paper);color:var(--ink);font:17px/1.65 var(--sans)}
a{color:var(--blue);text-underline-offset:3px}
:focus-visible{outline:3px solid var(--blue);outline-offset:3px}
.top{border-bottom:1px solid var(--line);background:var(--paper)}
.top .in{max-width:860px;margin:0 auto;padding:14px 24px;display:flex;justify-content:space-between;align-items:center;gap:16px}
.brand{font:700 1.1rem var(--serif);color:var(--ink);text-decoration:none}
main{max-width:860px;margin:0 auto;padding:44px 24px 64px}
h1{font:700 clamp(2rem,4vw,2.6rem)/1.15 var(--serif);margin:0 0 .6em}
h2{font:700 1.35rem/1.25 var(--serif);margin:2em 0 .5em;padding-top:.4em;border-top:1px solid var(--line)}
h3{font-size:1.02rem;margin:1.4em 0 .3em}
p,li{max-width:70ch}
ul{padding-left:1.2em}
address{font-style:normal}
.box{background:var(--sheet);border:1px solid var(--line);border-radius:12px;padding:18px 22px;margin:1em 0}
.muted{color:var(--muted)}
mark.todo{background:#FFE45C;color:#17202A;padding:0 .25em;border-radius:3px}
.toc{columns:2;column-gap:32px;padding-left:1.2em}
@media (max-width:620px){.toc{columns:1}}
footer{border-top:1px solid var(--line);padding:22px 24px 40px;font-size:.9rem;color:var(--muted)}
footer .in{max-width:860px;margin:0 auto;display:flex;flex-wrap:wrap;gap:8px 22px}
footer a,.linkbtn{color:var(--muted)}
.linkbtn{background:none;border:0;padding:0;font:inherit;text-decoration:underline;text-underline-offset:3px;cursor:pointer}