/* Course-notes book layout: static, sans-serif, reading-first.
   Type mirrors Google's blog aesthetic with self-hosted DM Sans — a geometric-
   humanist sans, the closest free stand-in for Google Sans. The woff2 files are
   staged next to this stylesheet, so sites stay fully offline. */

/* Self-hosted DM Sans — latin subset, variable weight (one file covers the whole
   range). Staged into <course>/assets/fonts/ alongside this file by build.ps1. */
@font-face {
  font-family: "DM Sans";
  font-style: normal;
  font-weight: 100 1000;
  font-display: swap;
  src: url("fonts/dmsans-latin.woff2") format("woff2");
}
@font-face {
  font-family: "DM Sans";
  font-style: italic;
  font-weight: 100 1000;
  font-display: swap;
  src: url("fonts/dmsans-latin-italic.woff2") format("woff2");
}

:root {
  --content-width: 42em;
  --font-body: "DM Sans", "Helvetica Neue", "Segoe UI", Roboto, Arial, sans-serif;
  --font-heading: "DM Sans", "Helvetica Neue", "Segoe UI", Roboto, Arial, sans-serif;
  --color-bg: #fefefe;
  --color-bg-elevated: #f6f6f6;
  --color-bg-subtle: #f8f8f8;
  --color-text: #444;
  --color-heading: #111;
  --color-muted: #666;
  --color-faint: #888;
  --color-link: #0645ad;
  --color-link-visited: #0b0080;
  --color-link-hover: #06e;
  --color-border: #ddd;
  --color-border-strong: #aaa;
  --color-code-bg: #f0f0f0;
  --color-image-bg: #fff;
  --color-button-bg: #fff;
  --color-selection: rgba(255, 235, 59, .35);
  --color-shadow: rgba(0, 0, 0, .12);
  color-scheme: light;
}

:root[data-theme="dark"] {
  --color-bg: #1e293b;
  --color-bg-elevated: #334155;
  --color-bg-subtle: #243044;
  --color-text: #cbd5e1;
  --color-heading: #f1f5f9;
  --color-muted: #94a3b8;
  --color-faint: #64748b;
  --color-link: #60a5fa;
  --color-link-visited: #b89cff;
  --color-link-hover: #93c5fd;
  --color-border: #334155;
  --color-border-strong: #475569;
  --color-code-bg: #334155;
  --color-image-bg: #fff;
  --color-button-bg: #334155;
  --color-selection: rgba(255, 235, 59, .2);
  --color-shadow: rgba(0, 0, 0, .5);
  color-scheme: dark;
}

* { box-sizing: border-box; }

html {
  background: var(--color-bg);
  color: var(--color-text);
  overflow-x: hidden;
  overflow-y: scroll;
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  max-width: var(--content-width);
  margin: 0 auto;
  padding: 1em;
  overflow-x: hidden;
  background: var(--color-bg);
  color: var(--color-text);
  font-family: var(--font-body);
  font-size: 14px;
  line-height: 1.7;
  overflow-wrap: break-word;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

::selection { background: var(--color-selection); color: #111; }

.skip-link {
  position: fixed;
  top: .5rem;
  left: .5rem;
  z-index: 100;
  transform: translateY(-160%);
  padding: .4rem .65rem;
  border: 1px solid var(--color-border);
  border-radius: 4px;
  background: var(--color-button-bg);
}
.skip-link:focus { transform: translateY(0); }

a { color: var(--color-link); text-decoration: none; }
/* No :visited recolour. On a notes site nearly every link is internal, so
   after one pass through a course the whole page turns visited-purple and the
   colour stops meaning anything. The author `a` rule above wins over the UA
   default, so every link keeps --color-link whether or not it has been
   followed. --color-link-visited is kept in the token block for restoring it. */
a:hover { color: var(--color-link-hover); }
a:focus-visible { outline: 2px solid var(--color-link); outline-offset: 2px; }

.theme-toggle {
  position: fixed;
  top: 0;                            /* share the reading bar's origin so the */
  height: 3.4rem;                    /* rem, not em: a <button>'s UA font-size */
                                     /* differs from the bar, so em would mismatch */
  right: .7em;
  z-index: 50;
  display: grid;
  width: 2.25rem;
  padding: .5rem;
  place-items: center;
  border: 0;
  border-radius: 50%;
  background: transparent;
  color: var(--color-muted);
  cursor: pointer;
}
.theme-toggle:hover { color: var(--color-heading); }
.theme-icon { display: block; width: 1.1rem; height: 1.1rem; }
.theme-icon-sun { display: none; }
:root[data-theme="dark"] .theme-icon-sun { display: block; }
:root[data-theme="dark"] .theme-icon-moon { display: none; }

/* Reading chrome (Google-blog style): a title bar that slides in once you
   scroll past the page header, with a slim scroll-progress bar riding along its
   bottom edge. Progressive — with JS off, neither intrudes. */
.reading-progress {
  position: absolute;
  left: 0;
  right: 0;
  bottom: -1px;                     /* sit on the bar's bottom border */
  height: 3px;
  background: transparent;
  pointer-events: none;
}
.reading-progress-fill {
  display: block;
  width: 0;
  height: 100%;
  background: var(--color-link);
  transition: width .1s linear;
}
.reading-bar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 40;
  display: flex;
  align-items: center;
  min-height: 3.4em;
  padding: .5em 3.5em;              /* keep the title clear of the theme toggle */
  background: color-mix(in srgb, var(--color-bg) 85%, transparent);
  backdrop-filter: saturate(180%) blur(8px);
  -webkit-backdrop-filter: saturate(180%) blur(8px);
  transform: translateY(-100%);
  opacity: 0;
  visibility: hidden;
  transition: transform .25s ease, opacity .25s ease, visibility .25s;
}
.reading-bar.is-visible {
  transform: translateY(0);
  opacity: 1;
  visibility: visible;
}
.reading-bar-title {
  display: block;
  width: 100%;
  max-width: var(--content-width);
  margin: 0 auto;
  padding: 0;
  border: 0;
  background: none;
  color: var(--color-heading);
  font-family: var(--font-heading);
  font-size: 1em;
  font-weight: 500;
  line-height: 1.3;
  text-align: center;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  cursor: pointer;
}
.reading-bar-title:hover { color: var(--color-link, var(--color-heading)); }
.reading-bar-title:focus-visible {
  outline: 2px solid var(--color-link, currentColor);
  outline-offset: 2px;
  border-radius: 3px;
}

.site-header { margin: 4.5em 0 3em; text-align: center; }
/* Up one level: topic/overview -> semester hub -> root chooser. The cards and
   the page nav only ever point downwards, so without this the only way back is
   the browser button. */
.parent-link {
  display: inline-block;
  margin: 0 0 1.6em;
  color: var(--color-muted);
  font-size: .9em;
  letter-spacing: .02em;
  text-decoration: none;
}
/* Colour alone marks the hover. An underline here used to sit on top of the
   global a:hover underline, which drew two rules under the link. */
.parent-link:hover,
.parent-link:focus-visible {
  color: var(--color-link);
}
.course-code {
  margin: 0 0 .35em;
  color: var(--color-heading);
  font-size: 1.35em;
  font-weight: 700;
  letter-spacing: .12em;
  text-transform: uppercase;
}
.site-title {
  margin: 0;
  color: var(--color-heading);
  font-family: var(--font-heading);
  font-weight: 500;
  letter-spacing: -.015em;
  font-size: 2.5em;
  line-height: 1.2;
}
.page-title {
  margin: .65em 0 1.5em;
  color: var(--color-muted);
  font-size: 1.05em;
  font-weight: normal;
  line-height: 1.4;
}

.page-nav {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: .35em 1.2em;
  margin: 0 auto 1.2em;
  font-size: .95em;
}
.page-nav a { padding: .15em .1em; }
.page-nav a[aria-current="page"] {
  color: var(--color-heading);
  font-weight: 700;
  text-decoration: underline;
  text-decoration-thickness: 1px;
  text-underline-offset: .25em;
}

.site-navigation {
  max-width: var(--content-width);
  margin: 1em auto 0;
  text-align: left;
  font-size: .9em;
}
.site-navigation > details {
  border: 1px solid var(--color-border);
  border-radius: 4px;
  background: var(--color-bg-subtle);
}
.site-navigation summary {
  padding: .45em .65em;
  color: var(--color-heading);
  font-weight: 700;
  cursor: pointer;
  user-select: none;
}
.site-navigation details[open] > summary {
  border-bottom: 1px solid var(--color-border);
}
.navigation-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: .55em;
  padding: .6em;
}
.navigation-group {
  min-width: 0;
  padding: .55em .65em;
  border: 1px solid var(--color-border);
  border-radius: 4px;
  background: var(--color-button-bg);
}
.navigation-group h2 {
  margin: 0 0 .2em;
  font-size: .95em;
  font-weight: 700;
}
.navigation-group ul {
  margin: 0;
  padding-left: 1.15em;
}
.navigation-group li {
  margin: .08em 0;
  line-height: 1.3;
}
/* A navigation entry with a label but no href: plain text, not a link. */
.navigation-text { color: var(--color-muted); }
.navigation-note {
  margin: .2em 0 0;
  color: var(--color-muted);
  font-size: .9em;
  line-height: 1.35;
}

.ecosystem {
  display: flex;
  flex-direction: column;
  gap: .8em;
  margin: 1em 0 2em;
}
.ecosystem-card {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 1em;
  padding: .8em 1.2em;
  border: 1px solid var(--color-border);
  border-radius: .35em;
  background: var(--color-bg-subtle);
  box-shadow: 0 4px 12px var(--color-shadow);
}
.ecosystem-card-text { min-width: 0; }
.ecosystem-card h3 {
  margin: 0 0 .15em;
  font-size: 1.05em;
  font-weight: 700;
}
.ecosystem-card p {
  margin: 0;
  color: var(--color-muted);
  font-size: .88em;
}
.ecosystem-btn {
  display: inline-flex;
  align-items: center;
  gap: .4em;
  padding: .35em .7em;
  border: 1px solid;
  border-radius: .3em;
  font-size: .85em;
  white-space: nowrap;
  text-decoration: none;
}
.ecosystem-btn svg { width: 14px; height: 14px; flex: none; }
.ecosystem-btn-pending {
  border-color: var(--color-border);
  background: transparent;
  color: var(--color-faint);
  font-style: italic;
  cursor: default;
}
.ecosystem-btn-pending svg { filter: grayscale(1); opacity: .45; }
.ecosystem-btn-icon { padding: .4em; font-style: normal; }
.ecosystem-btn-icon svg { width: 20px; height: 20px; }
/* Active state once a real URL replaces the pending span with an <a>. */
.ecosystem-btn-primary,
.ecosystem-btn-primary:link,
.ecosystem-btn-primary:visited {
  border-color: var(--color-link);
  background: color-mix(in srgb, var(--color-link) 10%, transparent);
  color: var(--color-link);
  font-style: normal;
}
.ecosystem-btn-primary:hover { text-decoration: none; opacity: .85; }

/* Icon-only buttons opt out of the link-blue frame. .ecosystem-btn-primary was
   written for a text+icon button, where blue chrome reads as "this is a link";
   around a full-colour brand mark the border and 10% tint just boxed the logo
   in a competing colour. Neutral chrome here, and the mark carries the colour. */
.ecosystem-btn-primary.ecosystem-btn-icon,
.ecosystem-btn-primary.ecosystem-btn-icon:link,
.ecosystem-btn-primary.ecosystem-btn-icon:visited {
  border-color: var(--color-border);
  background: var(--color-bg);
}
.ecosystem-btn-primary.ecosystem-btn-icon:hover {
  border-color: var(--color-border-strong);
  opacity: 1;
}

/* Semester hub: one card per subject, each linking to that course's overview.
   Used by the landing page at the notes root; inert everywhere else. Each card
   is authored on one line in index.md, so pandoc wraps it in a <p> — the grid
   items are those paragraphs, hence the margin reset. */
.subject-grid {
  display: grid;
  gap: .8em;
  margin: 1em 0 2em;
}
.subject-grid > p { margin: 0; }
.subject-card,
.subject-card:link,
.subject-card:visited {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  align-items: center;
  gap: 1em;
  padding: .9em 1.2em;
  border: 1px solid var(--color-border);
  border-radius: .35em;
  background: var(--color-bg-subtle);
  box-shadow: 0 4px 12px var(--color-shadow);
  color: var(--color-text);
}
.subject-card:hover {
  border-color: var(--color-link);
  color: var(--color-text);
  text-decoration: none;
}
.subject-card:hover .subject-name { color: var(--color-link); }
.subject-card:hover .subject-go { transform: translateX(.2em); }
.subject-card-text { min-width: 0; }
.subject-code {
  display: block;
  color: var(--color-muted);
  font-family: var(--font-heading);
  font-size: 1.15em;
  font-weight: 700;
  letter-spacing: .08em;
  line-height: 1.25;
  text-transform: uppercase;
}
.subject-name {
  display: block;
  margin: .1em 0 0;
  color: var(--color-heading);
  font-family: var(--font-heading);
  font-size: 1.15em;
  font-weight: 500;
  letter-spacing: -.01em;
  line-height: 1.25;
}
.subject-go {
  color: var(--color-faint);
  font-size: 1.2em;
  transition: transform .15s ease;
}
@media (prefers-reduced-motion: reduce) {
  .subject-go { transition: none; }
  .subject-card:hover .subject-go { transform: none; }
}

.navigation-group a[aria-current="page"] {
  color: var(--color-heading);
  font-weight: 700;
  text-decoration: underline;
  text-underline-offset: .18em;
}

.page-contents {
  margin: 1.2em 0 0;
  border-top: 1px solid var(--color-border);
  border-bottom: 1px solid var(--color-border);
  text-align: left;
}
.page-contents-title {
  margin: 0;
  padding: .55em .15em;
  color: var(--color-heading);
  font-weight: 700;
}

#TOC { padding: .1em .25em 1em; }
#TOC ul { margin: 0; padding-left: 1.4em; }
#TOC > ul { padding-left: 1.1em; }
#TOC li { margin: .12em 0; line-height: 1.45; }
#TOC a { display: inline-block; padding: .05em 0; }
#TOC ul ul { font-size: .92em; }
#TOC ul ul ul { color: var(--color-muted); font-size: .94em; }
.toc-section-number { color: var(--color-muted); }

main { min-width: 0; }

.course-pages {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(min(100%, 12rem), 1fr));
  gap: 1rem;
  margin: 2rem 0;
}
.course-page {
  padding: 1rem 1.1rem;
  border: 1px solid var(--color-border);
  border-radius: 4px;
  background: var(--color-bg-subtle);
}
.course-page h2 { margin: 0 0 .35rem; font-size: 1.25em; }
.course-page p { margin: .35rem 0; }

h1, h2, h3, h4, h5, h6 {
  position: relative;
  color: var(--color-heading);
  font-family: var(--font-heading);
  font-weight: 500;
  letter-spacing: -.01em;
  line-height: 1.25;
  hyphens: none;
  overflow-wrap: anywhere;
  scroll-margin-top: 3.75em;        /* clear the fixed reading bar on anchor jumps */
}
h1 { margin: 1.6em 0 .6em; font-size: 1.7em; }
h2 { margin: 1.6em 0 .5em; font-size: 1.35em; }
h3 { margin: 1.4em 0 .45em; font-size: 1.15em; }
h4 { margin: 1.3em 0 .4em; font-size: 1.02em; font-weight: 700; }
h5 { font-size: 1em; font-weight: 700; }
h6 { font-size: .9em; font-weight: 700; }
.header-section-number { color: var(--color-muted); margin-right: .25em; }

p { margin: 1em 0; }
ul, ol { padding-left: 1.8em; }
li { margin: .2em 0; }
dt { font-weight: 700; }
dd { margin: 0 0 1em 1.5em; }

/* Click-to-reveal answers on question pages. A list item's answer is authored
   as an `answer` environment; qa-details.lua turns each into a native <details>
   whose <summary> is the question (plus any options) and whose body is the
   answer. JavaScript-free; degrades to a plain open list where unstyled. */
.qa > summary {
  cursor: pointer;
  list-style: none;                 /* drop the browser's default triangle */
}
.qa > summary::-webkit-details-marker { display: none; }
.qa > summary:focus-visible {
  outline: 2px solid var(--color-link);
  outline-offset: 3px;
  border-radius: 3px;
}
/* Lettered options so answers referring to "a and d" line up with the choices. */
.qa > summary ol { list-style: lower-alpha; }
/* Our own caret, sitting at the end of the question stem. */
.qa-caret {
  display: inline-block;
  width: .5em;
  height: .5em;
  margin-left: .15em;
  border-right: 2px solid var(--color-faint);
  border-bottom: 2px solid var(--color-faint);
  transform: translateY(-.2em) rotate(45deg);      /* points down */
  transition: transform .15s ease, border-color .15s ease;
}
.qa[open] > summary .qa-caret {
  transform: translateY(.05em) rotate(-135deg);    /* points up */
}
.qa > summary:hover .qa-caret { border-color: var(--color-link); }
.qa-answer {
  margin: .5em 0 1em;
  padding: .6em .85em;
  border-left: 3px solid var(--color-border-strong);
  border-radius: 0 4px 4px 0;
  background: var(--color-bg-subtle);
}
.qa-answer > :first-child { margin-top: 0; }
.qa-answer > :last-child { margin-bottom: 0; }

blockquote {
  margin: 1.5em 0;
  padding-left: 1.5em;
  border-left: .35em solid var(--color-border);
  color: var(--color-muted);
}

hr {
  margin: 2em 0;
  border: 0;
  border-top: 1px solid var(--color-border-strong);
}

code, pre, kbd, samp {
  color: inherit;
  font-family: ui-monospace, "Cascadia Code", Consolas, monospace;
  font-size: .87em;
}
p code, li code, td code {
  padding: .12em .32em;
  border-radius: 3px;
  background: var(--color-code-bg);
}
pre {
  margin: 1.5em 0;
  padding: 1em 1.2em;
  overflow-x: auto;
  border: 1px solid var(--color-border);
  border-radius: 4px;
  background: var(--color-bg-elevated);
  line-height: 1.45;
  white-space: pre;
}
pre code { padding: 0; background: none; }

/* Raw algorithm2e blocks that pandoc can't convert come through as an empty
   <div class="algorithm">. A course that keeps algorithm2e in the source for the
   PDF (and ships a Verbatim code block for the web, e.g. sc1315) doesn't want the
   leftover empty div taking vertical space — hide it. */
.algorithm { display: none; }

/* Copy-to-clipboard button injected into each code block. The .code-wrapper is
   added at runtime by template.html's script (progressive enhancement — with JS
   off there is simply no button). Sits top-right, revealed on hover/focus. */
.code-wrapper { position: relative; }
.code-copy {
  position: absolute;
  top: .5em;
  right: .5em;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: .34em;
  color: var(--color-muted);
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: 5px;
  cursor: pointer;
  opacity: 0;
  transition: opacity .12s ease, color .12s ease, border-color .12s ease;
}
.code-copy svg { display: block; width: 15px; height: 15px; }
.code-wrapper:hover .code-copy,
.code-copy:focus-visible { opacity: 1; }
.code-copy:hover { color: var(--color-text); border-color: var(--color-border-strong); }
.code-copy.is-copied { color: var(--color-link); border-color: var(--color-link); opacity: 1; }
@media (hover: none) { .code-copy { opacity: 1; } }
@media print { .code-copy { display: none; } }

.table-wrap {
  max-width: 100%;
  margin: 1.5em auto 2em;
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
}
table {
  /* Fixed layout makes the <colgroup> percentages pandoc emits (from the
     source table's relative column widths) actually govern column sizing.
     Under the default auto layout, width: max-content sized each column by
     its longest UNWRAPPED line instead, which starved narrow columns (a "#"
     column next to a prose column) regardless of what the colgroup said. */
  width: 100%;
  table-layout: fixed;
  margin: 0 auto;
  border-collapse: collapse;
  font-size: .92em;
}
th, td {
  padding: .45em .7em;
  border: 1px solid var(--color-border);
  text-align: left;
  vertical-align: top;
  overflow-wrap: break-word;
}
th { background: var(--color-bg-elevated); text-align: center; }

/* MathML can't break internally, so a fixed-layout column narrower than an
   expression let it overflow its own cell with visible overflow, painting
   over the border and text of the next column — a table of bounds/limits
   collapsed into unreadable overlapping glyphs on narrow screens. Give such
   tables a floor width so .table-wrap's horizontal scroll takes over instead
   of squeezing columns below what their content can render at. */
/* MathML has no reliable internal line-breaking points. 32rem was enough for
   short formula tables, but a four-column definition table still squeezed a
   long quantified expression into its neighbour. Keep the table at a reading
   width and let its existing .table-wrap scroll horizontally on narrow pages. */
/* Do not use fixed column sizing for a mathematical table. Let its cells take
   their natural width, then rely on the surrounding .table-wrap for horizontal
   scrolling instead of allowing MathML to paint over the next cell. */
.table-wrap > table:has(math) {
  width: max-content;
  min-width: 100%;
  table-layout: auto;
}

img {
  max-width: 100%;
  height: auto;
  border: 0;
  background: var(--color-image-bg);
  vertical-align: middle;
}
figure { display: block; margin: 1.5em 0 2em; text-align: center; }
figure > img { display: block; margin: 0 auto; }
figure > img[src$=".svg"] { width: 100%; background: transparent; }
figcaption {
  margin: .65em auto 0;
  color: var(--color-muted);
  font-size: .82em;
  font-style: italic;
  line-height: 1.45;
}
figure:has(> figure) {
  display: flex;
  flex-wrap: wrap;
  gap: 1em 3%;
  justify-content: center;
  align-items: flex-start;
}
figure:has(> figure) > figure { flex: 0 1 auto; max-width: 47%; margin: 0; }
figure:has(> figure) > figure > img { width: auto; max-width: 100%; }
figure:has(> figure) > figcaption { flex-basis: 100%; }

.math.inline { white-space: normal; }
.math.display {
  display: block;
  max-width: 100%;
  margin: 1.35em 0;
  padding: .25em 0;
  overflow-x: auto;
  overflow-y: hidden;
  text-align: center;
}
math { color: inherit; font-size: 1em; }

/* The SC2301 revision sheet is deliberately denser than a lecture page.  Keep
   its content in normal Pandoc blocks so it still receives local MathML, then
   arrange those blocks as the two-column sheet used in the printable version. */
body:has(.cheatsheet) { max-width: min(100%, 90em); }
.cheatsheet {
  margin: 1.5em auto 2em;
  padding: .9em;
  background: var(--color-bg-elevated);
  border: 1px solid var(--color-border);
  border-radius: 5px;
}
.cheatsheet-sheet {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: .7em;
  align-items: start;
}
.cheatsheet-column {
  display: flex;
  flex-direction: column;
  gap: .55em;
  min-width: 0;
}
.cheatsheet-panel {
  padding: .3em .45em;
  border: 1px solid var(--color-border-strong);
  border-radius: 3px;
  background: var(--color-bg);
  font-size: .88em;
  line-height: 1.3;
}
.cheatsheet-panel p { margin: 0 0 .35em; }
.cheatsheet-panel ul,
.cheatsheet-panel ol { margin: 0 0 .35em; padding-left: 1.25em; }
.cheatsheet-panel li { margin: .12em 0; }
.cheatsheet-panel .table-wrap { margin: .35em 0 .5em; }
.cheatsheet-panel table { font-size: 1em; }
.cheatsheet-panel th,
.cheatsheet-panel td { padding: .16em .24em; }
.cheatsheet-section-title,
.cheatsheet-subsection-title {
  margin: -.35em -.55em .4em;
  padding: .18em .4em;
  color: #fff;
  font-weight: 700;
  line-height: 1.2;
}
.cheatsheet-section-title { background: #063665; }
.cheatsheet-subsection-title {
  margin-top: .45em;
  background: #8b1a1a;
  font-size: .92em;
}

@media (max-width: 720px) {
  body:has(.cheatsheet) { max-width: var(--content-width); }
  .cheatsheet { padding: .55em; }
  .cheatsheet-sheet { grid-template-columns: 1fr; }
  .cheatsheet-panel { font-size: .9em; }
}

.sequence-navigation {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
  gap: 1em;
  margin: 3em 0 1em;
  padding-top: 1.25em;
  border-top: 1px solid var(--color-border);
}
.sequence-navigation a {
  overflow-wrap: anywhere;
}
.sequence-navigation .next-page { text-align: right; }

.site-footer {
  margin-top: 2em;
  padding: 20px;
  color: var(--color-faint);
  font-size: .82em;
  text-align: center;
}
.site-footer p { margin: 1.1em 0 0; color: var(--color-text); font-size: 1.2rem; }
.footer-socials {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 20px;
}
.footer-socials a {
  display: grid;
  width: 40px;
  height: 40px;
  place-items: center;
  color: var(--color-heading);
}
.footer-socials a:hover { opacity: .72; }
.footer-socials svg { width: 40px; height: 40px; fill: currentColor; }

@media (min-width: 480px) { body { font-size: 15px; } }
@media (min-width: 768px) { body { padding-inline: 1.25em; font-size: 16px; } }

@media (max-width: 520px) {
  .site-header { margin-top: 3.75em; }
  .site-title { font-size: 2.05em; }
  h1 { font-size: 1.55em; }
  h2 { font-size: 1.3em; }
  figure:has(> figure) { flex-direction: column; align-items: center; }
  figure:has(> figure) > figure { max-width: 92%; }
  .navigation-grid { grid-template-columns: 1fr; }
}

@media (min-width: 521px) and (max-width: 720px) {
  .navigation-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .reading-bar, .reading-progress-fill { transition: none; }
}

@media print {
  :root, :root[data-theme="dark"] { color-scheme: light; }
  * { background: transparent !important; color: #000 !important; box-shadow: none !important; }
  body { max-width: 100%; padding: 0; font-size: 11pt; }
  .theme-toggle, .skip-link, .page-contents, .page-nav, .site-footer,
  .reading-bar, .reading-progress { display: none !important; }
  .site-header { margin: 0 0 2em; }
  a { text-decoration: underline; }
  pre, blockquote, figure, table { break-inside: avoid; }
}