:root {
  color-scheme: light dark;
  --bg: #f5f6f3;
  --paper: #ffffff;
  --ink: #202d38;
  --heading: #142d40;
  --muted: #596671;
  --link: #145975;
  --line: #dce1e2;
  --surface: #f0f4f5;
  --surface-hover: #f8fafb;
  --code-bg: #f3f5f6;
  --focus: #a65e08;
  --img-bg: #ffffff;
  --img-padding: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  font-size: 17px;
  line-height: 1.7;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0f1419;
    --paper: #182026;
    --ink: #dce4ec;
    --heading: #f0f5fa;
    --muted: #8b9ba8;
    --link: #5da9d6;
    --line: #2d3844;
    --surface: #1f2933;
    --surface-hover: #232f3b;
    --code-bg: #141b22;
    --focus: #e59b3c;
    --img-bg: #ffffff;
    --img-padding: 0;
  }
}
* { box-sizing: border-box; }
body { margin: 0; }
a { color: var(--link); text-underline-offset: .18em; }
a:hover { text-decoration-thickness: 2px; }
a:focus-visible, summary:focus-visible { outline: 3px solid var(--focus); outline-offset: 4px; }
.skip-link { position: absolute; left: 1rem; top: -6rem; padding: .5rem; background: var(--paper); color: var(--link); border: 1px solid var(--line); }
.skip-link:focus { top: 1rem; z-index: 2; }
.masthead { display: flex; align-items: baseline; flex-wrap: wrap; gap: .5rem 1.2rem; max-width: 1160px; margin: auto; padding: 1.4rem 2rem; }
.brand { font-weight: 750; font-size: 1.3rem; letter-spacing: -.035em; text-decoration: none; color: var(--ink); }
.masthead > span { color: var(--muted); font-size: .85rem; }
.masthead nav { margin-left: auto; display: flex; flex-wrap: wrap; gap: 1.2rem; font-size: .85rem; }
main { max-width: 1160px; margin: 0 auto; padding: 2.6rem 3rem; background: var(--paper); border: 1px solid var(--line); border-radius: 6px; }
h1, h2, h3, h4 { line-height: 1.25; color: var(--heading); scroll-margin-top: 1rem; }
h1 { font-family: Georgia, "Times New Roman", serif; font-size: clamp(2rem, 4vw, 3rem); font-weight: 500; letter-spacing: -.035em; margin-top: 0; }
h2 { font-size: 1.5rem; margin-top: 2rem; }
h3 { font-size: 1.15rem; margin-top: 1.8rem; }
p, ul, ol, blockquote { max-width: 85ch; }
p { margin: .9rem 0; }
table { width: 100%; border-collapse: collapse; font-size: .9rem; margin: 1.6rem 0; display: block; overflow-x: auto; }
th, td { padding: .8rem 1rem; border-bottom: 1px solid var(--line); text-align: left; vertical-align: top; }
th { font-size: .78rem; text-transform: uppercase; letter-spacing: .045em; background: var(--surface); }
tbody tr:hover { background: var(--surface-hover); }
img { max-width: 100%; height: auto; display: block; margin: 1.5rem auto; background: var(--img-bg); padding: var(--img-padding); border-radius: 4px; }
pre { overflow-x: auto; padding: 1rem; background: var(--code-bg); border-radius: 4px; }
code { font-size: .9em; }
blockquote { margin-left: 0; padding-left: 1.2rem; border-left: 3px solid var(--line); color: var(--muted); }
.contents { margin: 0 0 2rem; padding: .8rem 1rem; border: 1px solid var(--line); border-radius: 4px; background: var(--surface-hover); }
.contents summary { cursor: pointer; font-weight: 600; }
.contents ul { font-size: .9rem; line-height: 1.6; }
.math.display { display: block; overflow-x: auto; padding: .4rem 0; }
mjx-container[display="true"] { overflow-x: auto; overflow-y: hidden; max-width: 100%; padding: .2rem 0; }
footer { max-width: 1160px; margin: auto; padding: 1.4rem 2rem 2.4rem; color: var(--muted); font-size: .8rem; }
@media (max-width: 640px) {
  :root { font-size: 16px; }
  main { padding: 1.6rem 1.15rem; border-radius: 0; border-left: 0; border-right: 0; }
  .masthead { padding: 1rem 1.15rem; }
  .masthead nav { width: 100%; margin-left: 0; gap: .8rem; }
  th, td { padding: .6rem .65rem; }
  footer { padding: 1.2rem 1.15rem; }
}