/* Independent English reader; native MathML, no downloaded fonts or scripts. */
:root {
  color-scheme: light;
  --paper: #fffefa;
  --ink: #202731;
  --muted: #4b5665;
  --accent: #194f80;
  --rule: #c9d2dd;
  --panel: #f1f5fa;
}
* { box-sizing: border-box; }
html {
  background: #e9edf2;
  color: var(--ink);
  font-family: "Noto Serif", "Libertinus Serif", Georgia, serif;
  font-size: 18px;
  line-height: 1.65;
  scroll-padding-top: 1rem;
}
body {
  width: min(100% - 2rem, 58rem);
  margin: 2rem auto;
  padding: clamp(1.1rem, 4vw, 3.2rem);
  background: var(--paper);
  box-shadow: 0 .3rem 1.6rem rgb(24 35 52 / 10%);
}
main, header, footer, nav, details, section, figure { min-width: 0; max-width: 100%; }
main { overflow-wrap: break-word; }
h1, h2, h3, h4, h5, h6 { line-height: 1.25; overflow-wrap: anywhere; }
h1, h2 { color: var(--accent); }
h1 { font-size: 1.9rem; }
h2 { margin-top: 2.4rem; font-size: 1.5rem; }
h3 { font-size: 1.2rem; }
a { color: var(--accent); overflow-wrap: anywhere; text-underline-offset: .15em; }
a:hover { text-decoration-thickness: .14em; }
:focus-visible { outline: 3px solid var(--accent); outline-offset: 3px; }
.skip-link {
  position: absolute;
  top: .5rem;
  left: -10000px;
  z-index: 10;
  padding: .6rem 1rem;
  background: var(--paper);
  border: 2px solid var(--accent);
}
.skip-link:focus { left: .5rem; }
.edition-label, .source-provenance, footer { color: var(--muted); font-size: .88rem; }
.source-provenance { border-top: 1px solid var(--rule); padding-top: .7rem; margin: 2rem 0 3rem; }
.book-header { border-bottom: 2px solid var(--rule); padding-bottom: 1rem; }
.contents { background: var(--panel); border: 1px solid var(--rule); padding: 1rem; margin: 1.6rem 0; }
summary { cursor: pointer; font-weight: bold; }
#TOC ul { padding-inline-start: 1.5rem; }
#TOC > ul { padding-inline-start: 1.1rem; }
#TOC li { margin-block: .4rem; }
nav a[aria-current="page"] { font-weight: bold; }
/* The page itself never becomes a horizontal-scroll container for equations. */
.display-math {
  display: block;
  width: 100%;
  max-width: 100%;
  min-width: 0;
  overflow-x: auto;
  overflow-y: hidden;
  padding: .7rem .25rem;
  margin-block: .55rem;
  overscroll-behavior-x: contain;
}
.display-math math[display="block"] { width: max-content; min-width: 100%; margin-block: 0; }
math { font-family: "STIX Two Math", "Cambria Math", "Latin Modern Math", math; }
/* Long inline expressions retain their place in prose but scroll within their
   own line box on narrow screens instead of widening the entire reader. */
math:not([display="block"]) {
  display: inline-block;
  max-width: 100%;
  overflow-x: auto;
  overflow-y: hidden;
  vertical-align: -0.2em;
}
img, svg { display: block; max-width: 100%; height: auto; margin: 1.2rem auto; }
figure { margin-inline: 0; }
figcaption { color: var(--muted); font-size: .9rem; text-align: center; }
.definition, .theorem, .lemma, .example, .exercise, .note {
  margin-block: 1.4rem;
  padding: 1rem;
  border-inline-start: .25rem solid var(--accent);
  background: var(--panel);
}
table { display: block; max-width: 100%; overflow-x: auto; border-collapse: collapse; }
th, td { padding: .45rem .7rem; border: 1px solid var(--rule); }
code, pre { font-family: ui-monospace, "Cascadia Mono", monospace; }
code { overflow-wrap: anywhere; }
pre { max-width: 100%; overflow-x: auto; padding: .8rem; background: var(--panel); }
blockquote { margin-inline: 1rem; padding-inline-start: 1rem; border-inline-start: 2px solid var(--rule); }
footer { border-top: 2px solid var(--rule); margin-top: 3rem; padding-top: 1rem; }
@media (max-width: 42rem) {
  html { font-size: 16px; }
  body { width: 100%; margin: 0; padding: 1rem; box-shadow: none; }
  h1 { font-size: 1.65rem; }
  .contents { padding: .75rem; }
}
@media (prefers-reduced-motion: reduce) { html { scroll-behavior: auto; } }
@media print {
  html, body { background: white; }
  body { width: auto; margin: 0; padding: 0; box-shadow: none; }
  .skip-link, .book-header nav, footer > p:first-child { display: none; }
  a { color: inherit; }
}