/* #region Font face declarations */

/* #endregion */

:root {
  --text: 'Linux Libertine__subset', serif;
  --secondary: 'Linux Biolinum__subset', sans-serif;
  --display: 'Hypersystem__subset', Chicago, Fixedsys, Impact, sans-serif;
  --code: Berkeley Mono, Consolas, monospace, monospace;

  --link-color: light-dark(#145591, #76eff5);
  --bg: light-dark(#f8fafb, #050505);
  --fg: light-dark(#121210, #f8fafb);
  --line-color: light-dark(#3a3a37, #777);

  --max-width: 43rem;
  --width: min(calc(100vw - 2em), var(--max-width));
  --page-margin: calc((100vw - var(--width)) / 2);

  background-color: var(--bg);
  color: var(--fg);

  font-family: var(--text);
  font-size: calc((18 / 16) * 100%);
  line-height: 1.5em;

  padding: 0 1em;
  margin: 0 var(--page-margin) 3em;

  color-scheme: light dark;
}

body {
  margin: 0;
}

h1, h2, h3, h4, h5, h6 {
  font-family: var(--display);
  font-weight: normal;
  line-height: 1.2em;
  text-wrap: balance;
}

h1 {
  font-size: 2em;
  margin-block-start: 1.5em;
  margin-block-end: 1em;
}

h2 {
  font-size: 1.5em;
  margin-block-start: 1.5em;
  margin-block-end: 1em;
}

h3 {
  font-size: 1.25em;
  margin-block-start: 1.5em;
  margin-block-end: 1em;
}

h4 {
  font-size: 1em;
  margin-block-start: 1.5em;
  margin-block-end: 1em;
}

figure {
  margin-inline: 1em;
}

figcaption, ol::marker, ul::marker, header, footer {
  font-family: var(--secondary);
}

header, footer {
  font-size: 0.8em;

  h1 {
    font-size: 2.8em;
  }
}

pre {
  overflow-x: auto;
  margin-inline-end: calc((100% - 100vw) / 2);
  padding-block: .75em;
  margin-block: -.75em;

  #html-note &, #important &, #sidebar & {
    margin-inline-end: -2em;
  }
}

pre, code, samp, kbd {
  font-family: var(--code);
}

pre, code:not(pre code) {
  line-height: 1.2em;
  font-size: .9em;
}

ul, ol {
  padding-inline-start: 1.5em;
}

ol li::marker {
  font-family: var(--secondary);
  font-variant-numeric: oldstyle-nums;
}

ul[role=list] {
  list-style: none;
  padding-inline-start: 0;

  & & {
    padding-inline-start: 1em;
  }
}

dt {
  font-weight: bold;
  font-style: normal;
}

blockquote {
  font-style: italic;
  padding-inline: 1em;
  margin-inline: 0;
  border-inline-start: 1px dotted var(--line-color);
}

a {
  color: var(--link-color);
}

sub, sup {
  line-height: 1em;
}

img {
  max-width: 100%;
  height: auto;
}

label {
  font-family: var(--secondary);
}

.smallcaps {
  font-variant-caps: small-caps;
}

.book-header {
  display: none;
  /* margin-block: .5em;
  @media (prefers-color-scheme: dark) {
    background: rgb(37, 42, 53);
  }

  .homepage-link {
    font-family: var(--display);
    font-weight: 900;
    text-transform: uppercase;
    pointer-events: all;
    text-decoration: none;

    &:hover, &:focus-visible, &:active {
      color: rgb(14, 19, 65);
      @media (prefers-color-scheme: dark) {
        color: rgb(215, 215, 242);
      }
    }
  }

  + .navigation-footer nav {
    margin-block-start: .2em;
  } */
}

.buy-it {
  > a {
    display: grid;
    margin-block: .2em;

    grid-auto-flow: dense;
    justify-content: start;
    gap: 0 .5em;

    font-family: var(--secondary);
    font-weight: bold;
    line-height: 1em;

    background: light-dark(rgb(215, 215, 242), rgb(37, 42, 53));
    color: light-dark(rgb(14, 19, 65), rgb(215, 215, 242));
    border: 1px solid light-dark(rgb(115, 115, 170), rgb(115, 115, 170));

    text-decoration: none;
    padding: .4em;

    &:hover, &:focus, &:active {
      background: light-dark(rgb(200, 200, 239), rgb(26, 47, 80));
    }

    small {
      font-weight: normal;
      grid-column: 2;
    }

    &:has(picture) {
      justify-content: space-between;
      small { grid-column: 1; }
    }

    picture {
      grid-column: 2;
      grid-row: 1 / span 2;
      max-height: 3em;
      img {
        max-height: inherit;
      }
    }
  }
}

.table-of-contents {
  counter-reset: chapter 0;

  ul {
    column-width: 30ch;
    column-gap: 2em;
    display: flow-root;
    margin-block: 1.4em;
    padding-inline: 0 !important;
  }

  li + li {
    margin-block-start: 1.4em;
  }

  ul.internal-contents {
    display: none;
    grid-column: 1 / span 2;
    margin-block: 0;
    padding-inline-start: 4em !important;

    & & {
      margin-block: 1.4em;
    }
  }

  a {
    text-decoration: none;

    &:hover, &:focus-visible, &:active {
      text-decoration: underline;
    }

    .part > & {
      font-family: var(--display);
    }
  }

  .chapter {
    counter-increment: chapter;

    display: grid;
    grid-template-columns: min-content 1fr;
    gap: 1em;
    align-items: baseline;

    &::before {
      content: counter(chapter, decimal-leading-zero);
      font-family: var(--display);
      font-size: .9em;
    }

    &.introduction {
      counter-increment: none;

      &::before {
        content: "☛";
        font: inherit;
      }
    }
  }
}

.part-children {
  font-family: var(--secondary);
  .part-child {
    margin-block: 1em;
  }
  a:not(:hover, :focus-visible, :active) {
    text-decoration: none;
  }
}

.division-header {
  margin-block: 3rem 2rem;
  margin-inline: calc(-1 * var(--page-margin));
  padding: 0 var(--page-margin);

  border-bottom: 1px dotted var(--line-color);
}

.division-toc {
  font-family: var(--secondary);

  summary {
    font-size: inherit;
    font-weight: bold;
  }

  li {
    margin-block: .5em;
  }

  a:not(:hover, :focus-visible, :active) {
    text-decoration: none;
  }
}

.division-content {
  margin-block: 1em 4em;
}

.navigation-footer {
  & ~ & {
    font-size: 1.1em;
  }
}

.navigation {
  margin-block: 1em;

  display: flex;
  flex-flow: row wrap;
  justify-content: start;
  gap: .2em;

  p {
    display: contents;
  }

  a {
    flex: 1 0 15ch;

    font-family: var(--secondary);
    font-size: .9em;
    line-height: 1.4em;
  }

  [rel=next] {
    font-weight: bold;
    text-align: end;
  }
}

#sidebar, #important, #html-note {
  font-size: .8em;
  line-height: 1.5em;
  padding: 0 1em;
  display: flow-root;
  font-family: var(--secondary);

  background: light-dark(rgb(245, 245, 245), rgb(30, 30, 30));
  border-block: 1px solid light-dark(rgb(78, 78, 78), rgb(159, 159, 159));
}

#important {
  background: light-dark(rgb(207, 232, 253), rgb(28, 32, 83));
  border-block: 1px solid light-dark(rgb(23, 61, 111), rgb(74, 89, 230));
}

#html-note {
  background: light-dark(rgb(230, 230, 246), rgb(20, 22, 43));
  border-block: 1px solid light-dark(rgb(34, 64, 104), rgb(74, 89, 230));

  h2 {
    font-size: 1em;
    font-family: var(--secondary);
    font-weight: bold;
  }
}

.quote-attribution {
  margin-block-start: -1.3em;
  padding-inline-start: 1em;
  text-align: right;
  border-inline-start: 1px dotted var(--line-color);
}

.footnotes {
  font-size: .8em;
  font-family: var(--secondary);
  margin-block: 3em 1em;
  hr {
    display: none;
  }
  .footnote-back {
    font-size: .8em;
    text-decoration: none;
  }
}

.footnote-ref {
  text-decoration: none;
  sup {
    text-decoration: 1px solid currentcolor;
  }
}

.book-footer {
  margin-block: 3em;
  font-size: .8em;
  font-family: var(--secondary);
  text-align: center;

  display: flex;
  flex-flow: row wrap;
  justify-content: center;
  gap: 1em;

  .footer-book-title {
    font-family: var(--display);
  }
}

color-customizer {
  h2 {
    margin-inline: 2em;
  }
  form {
    margin: 2em;
    display: grid;
    grid-template-columns: 1fr auto;
    gap: .5em;
    justify-items: start;
    label {
      display: contents;
    }
    .buttons {
      grid-column: 1/-1;
      display: flex;
      flex-flow: row wrap;
      justify-content: space-around;
      justify-self: stretch;
      padding-block: .5em;
    }
  }
}

.kw, .cf, .bu, .ex, .pp, .at, .in, .wa {
  font-weight: bold;
}
.dt, .dv, .bn, .fl, .ch, .st, .co, .ot, .al, .fu, .re, .er, .cn, .sc, .vs, .ss, .im, .do, .an, .cv, .va, .op {
  color: light-dark(#777, #bbb);
}