:root {
  --color-text: 0, 0, 0;
  --color-background: 255, 255, 255;
  --color-link: 0, 0, 0;
  --type-base: calc(1.6em + 0.5vw);
  --type-xxxx-small: 30%;
  --type-xxx-small: 55%;
  --type-xx-small: 65%;
  --type-x-small: 75%;
  --type-small: 85%;
  --type-medium: 100%;
  --type-large: 120%;
  --type-x-large: 160%;
  --type-xx-large: 200%;
  --type-xxx-large: 300%;
  --type-xxxx-large: 400%;
}

*,
*:before,
*:after {
  box-sizing: border-box;
}

::selection {
  color: rgb(var(--color-background));
  background-color: rgb(var(--color-text));
}

::-moz-selection {
  color: rgb(var(--color-background));
  background-color: rgb(var(--color-text));
}

html {
  font-size: 16px;
}

@supports(display: grid) {

  html {
    font-size: 10px;
  }

}

body {
  margin: 0;
  padding: 0;
  font-family: ff-meta-serif-web-pro, serif;
  font-size: var(--type-base);
  color: rgb(var(--color-text));
  background-color: rgb(var(--color-background));
  overflow-x: hidden;
}

h1,
h2,
h3,
h4,
h5,
h6 {
  margin: 1.5em 0 0 0;
  padding: 0;
  align-items: center;
  font-size: var(--type-large);
  font-weight: bold;
  line-height: 1.2;
}

h1:hover .anchor-link,
h2:hover .anchor-link,
h3:hover .anchor-link,
h4:hover .anchor-link,
h5:hover .anchor-link,
h6:hover .anchor-link {
  opacity: 1;
}

h1 {
  font-size: var(--type-xx-large);
}

h2 {
  font-size: var(--type-x-large);
}

h3 {
  margin-bottom: -0.25em;
}

h3 + h4 {
  margin-top: 1.5em;
}

h4 {
  font-size: var(--type-small);
  margin-top: 1.25em;
}

h4 + p,
h4 + ol,
h4 + ul {
  margin-top: 0.2em;
}

p {
  margin: 1em 0 0 0;
  font-size: var(--type-medium);
  line-height: 1.5;
}

ul,
ol {
  margin: 1em 0 0 1em;
  padding: 0;
  line-height: 1.5;
}

ol ul,
ul ul {
  margin-top: 0;
}

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

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

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

hr {
  height: 0;
  margin: 3em 0;
  border: 0;
  border-top: 0.1rem solid rgb(var(--color-text));
}

blockquote {
  font-style: italic;
  margin: 1em 0 0 0;
  padding: 0 0 0 1em;
  border-left: 0.2rem solid rgb(var(--color-text));
}

code {
  position: relative;
  padding: 0.25rem 0.5rem;
  border-radius: 0.2rem;
  background-color: rgba(var(--color-link), 0.075);
  font-size: var(--type-x-small);
  font-family: SFMono-Regular, Consolas, Liberation Mono, Menlo, Courier, monospace;
}

img {
  max-width: 100%;
  border-radius: 1rem;
}

figure {
  margin: 1em 0 2em 0;
  break-inside: avoid;
  text-align: center;
}

figcaption {
  margin: 0.25em 0 0 0;
  font-size: var(--type-small);
  font-style: italic;
}



.wb {
  width: 100%;
  margin: 0 auto;
  padding: 1.5em;
  display: grid;
  grid-template-areas: 'header' 'sidebar' 'content' 'footer';
  grid-template-columns: auto;
}



.landing-title {
  margin: 0 0 0.25em 0;
  font-size: var(--type-xx-large);
  font-weight: bold;
  line-height: 1.1;
}

.landing-title--large {
  margin: 0;
  font-size: var(--type-xxx-large);
}

.landing-version {
  font-size: var(--type-xxxx-small);
  font-weight: normal;
  font-style: italic;
}

.landing-subtitle {
  margin: 0;
  font-size: var(--type-xx-large);
  line-height: 1.2;
}

.landing-author {
  margin: 0;
  font-size: var(--type-small);
  font-style: italic;
}

.landing-image {
  display: block;
  margin: 3em 0 1em 0;
}



.intro {
  grid-area: sidebar;
}

.intro__book-title {
  margin: 0 0 2em 0;
}

.intro__book-title .icon {
  flex-shrink: 0;
  margin-right: 0.75em;
}

.intro__book-title--compact {
  white-space: nowrap;
  font-size: var(--type-small) !important;
  padding: 0.5em 1em !important;
}

.intro__book-title--compact .icon {
  display: none;
}

.intro__masthead {
  margin: 2em 0 0 0;
  padding: 0.5em 0 0 0;
  text-transform: uppercase;
  letter-spacing: 0.3rem;
  font-size: var(--type-xx-small);
}

.intro__masthead + .intro__title {
  margin: 0;
}

.intro__title {
  margin: 0.58em 0 0 0;
  font-size: var(--type-xx-large);
}

.intro__title a {
  text-decoration: none;
}

.intro__sections {
  display: none;
}

.intro__section {
  font-size: var(--type-small);
  font-style: italic;
}

.intro__next {
  display: none;
}



.pagination {
  margin: 0;
  padding: 1em 0 0 0;
}



.content {
  margin: 0;
  padding: 0;
  grid-area: content;
  position: relative;
}



.footer {
  margin: 4em 0 0 0;
  padding: 1em 0;
  border-top: 0.1rem solid rgb(var(--color-text));
}

.footer__copyright {
  font-size: var(--type-x-small);
}



.hidden {
  display: none;
}



.sr-only {
  border: 0;
  clip: rect(0 0 0 0);
  height: 1px;
  margin: -1px;
  overflow: hidden;
  padding: 0;
  position: absolute;
  width: 1px;
}



.page-break {
  page-break-before: always;
}



.linebreak {
  display: none;
}



.warning {
  grid-area: header;
  margin: 0 0 2em 0;
  border: 0.1rem solid rgb(var(--color-text));
  padding: 1em;
  font-size: var(--type-small);
  text-align: center;
}

@supports(display: grid) {

  .warning {
    display: none;
  }

}



.anchor-link {
  display: inline-block;
  width: 0;
  opacity: 0;
  margin-left: 0.125em;
  transition: opacity 0.2s ease-in-out 0.1s;
  text-decoration: none;
}



.icon {
  width: 2rem;
  height: 2rem;
}

.icon path {
  fill: rgb(var(--color-text));
}

.icon--twitter {
  width: 2.5rem;
  height: 2.5rem;
}

.icon--twitter path {
  fill: rgb(var(--color-background));
}



.button {
  display: inline-flex;
  align-items: center;
  padding: 0.5em 0.75em;
  border: 0.2rem solid rgb(var(--color-link));
  background-color: rgb(var(--color-link));
  color: rgb(var(--color-background));
  border-radius: 1.25em;
  font-size: inherit;
  font-family: inherit;
  font-weight: bold;
  line-height: 1.25;
  cursor: pointer;
  outline: none;
  text-decoration: none;
}

.button:hover,
.button:active,
.button:visited {
  color: rgb(var(--color-background));
}

.button:focus-visible {
  outline: 0.2rem solid rgb(var(--color-background));
  outline-offset: 0.2rem;
}

.button .icon path {
  fill: rgb(var(--color-background));
}

.button--reversed {
  background-color: transparent;
  border: 0;
}

.button--reversed .icon path {
  fill: rgb(var(--color-text));
}

.button--reversed:hover,
.button--reversed:active,
.button--reversed:visited {
  background-color: transparent;
}

.button--ghost {
  color: rgb(var(--color-text));
  background-color: transparent;
}

.button--ghost .icon path {
  fill: rgb(var(--color-text));
}

.button--ghost:hover,
.button--ghost:active,
.button--ghost:visited {
  color: rgb(var(--color-text));
  background-color: transparent;
}

.button--hidden {
  display: none;
}



.pop {
  display: inline-flex;
  max-width: 20em;
  padding: 0.75em;
  background-color: rgb(var(--color-text));
  color: rgb(var(--color-background));
  border-radius: 0.5rem;
  z-index: 100;
  font-size: var(--type-small);
  font-style: italic;
  transition: opacity 0.1s ease-in-out;
  opacity: 0;
  visibility: hidden;
}

.pop--visible {
  opacity: 1;
  visibility: visible;
}

.pop__arrow {
  position: absolute;
  width: 0;
  height: 0;
  margin: 0;
  border-style: solid;
  border-width: 0.5rem;
  border-color: transparent;
}

.pop[x-placement^=bottom] {
  margin-top: 0.5rem;
}

.pop[x-placement^=bottom] .pop__arrow {
  border-top-width: 0;
  border-bottom-color: rgb(var(--color-text));
  top: -0.5rem;
  left: calc(50% - 0.5rem);
}

.pop[x-placement^=top] {
  margin-bottom: 0.5rem;
}

.pop[x-placement^=top] .pop__arrow {
  border-bottom-width: 0;
  border-top-color: rgb(var(--color-text));
  bottom: -0.45rem;
  left: calc(50% - 0.5rem);
}



.modal-open {
  overflow: hidden;
}



.menu {
  position: fixed;
  top: 0;
  bottom: 0;
  left: 0;
  max-width: 30em;
  overflow-y: auto;
  visibility: hidden;
  padding: 1em 2em;
  opacity: 0;
  background-color: rgba(var(--color-background), 1);
  transition: all 0.3s ease-in-out;
  transform: translate(-100%, 0);
  box-shadow: 0 0 1em 0 rgba(0, 0, 0, 0.1);
  -webkit-overflow-scrolling: touch;
}

.menu--show {
  visibility: visible;
  opacity: 1;
  transform: translate(0, 0);
}

.menu__close {
  position: absolute;
  top: 1em;
  right: 1em;
}

@supports(-webkit-backdrop-filter: blur()) {

  .menu {
    -webkit-backdrop-filter: blur(15px);
    background-color: rgba(var(--color-background), 0.6);
  }

}



.book-info {
  margin: 0 0 2em 0;
}

.book-info__back {
  margin: 0.5em 0 1em 0;
  font-size: var(--type-small);
}

.book-info__title {
  margin: 1em 0 0.25em 0;
  font-size: var(--type-xx-large);
}

.book-info__subtitle {
  margin: 0;
  font-weight: bold;
}

.book-info__author {
  margin: 0;
  font-style: italic;
}

.book-info__buy {
  margin: 1em 0 0 0;
}



.toc__part-title {
  display: block;
  margin: 2em 0 0 0;
  padding: 0.5em 0 0 0;
  border-top: 0.1rem solid rgb(var(--color-text));
}

.toc__chapters {
  margin: 0;
  padding: 0;
  list-style-type: none;
}

.toc__chapter {
  margin: 1em 0 1em 0;
  padding: 0 3em 0 0;
}

.toc__chapter-number {
  margin: 3em 0 0 0;
  text-transform: uppercase;
  letter-spacing: 0.3rem;
  font-size: var(--type-xx-small);
}

.toc__chapter-number + .toc__chapter-title {
  margin: 0;
}

.toc__chapter-title {
  margin: 2em 0 0 0;
}

.toc__chapter-title--compact {
  margin: 0;
}

.toc__sections {
  margin: 0.5em 0 0 0;
  padding: 0 0 0 0.5em;
  list-style-type: none;
  border-left: 0.1rem solid rgb(var(--color-link));
}

.toc__section {
  font-size: var(--type-small);
  font-style: italic;
}



.glossary__title {
  margin: 2em 0 0 0;
  padding: 0.5em 0 0 0;
  border-top: 0.1rem solid rgb(var(--color-text));
}

.glossary__entry-title {
  margin: 1em 0 0 0;
  font-weight: bold;
}

.glossary__entry-definition {
  margin: 0;
  font-size: var(--type-small);
  font-style: italic;
}



@media screen and (min-width: 50em) {

  :root {
    --type-base: calc(0.9em + 0.9vw);
  }

  .wb {
    margin: 0;
    padding: 2em;
    grid-template-areas: 'header header' 'sidebar content' 'footer footer';
    grid-template-columns: 0.85fr 2.5fr;
  }

  .landing-title {
    font-size: var(--type-xxx-large);
  }

  .landing-title--large {
    font-size: var(--type-xxxx-large);
  }

  .landing-image {
    margin: 0 0 1em 0;
  }

  .intro__book-title {
    margin: 0;
  }

  .intro__sections {
    display: block;
    margin: 0.5em 0 0 0;
    padding: 0;
    list-style-type: none;
  }

  .intro__next {
    display: block;
    font-size: var(--type-small);
  }

  .intro__content {
    position: relative;
    top: 2.5em;
    text-align: center;
  }

  .intro__content {
    text-align: right;
  }

  .intro__content--sticky {
    position: -webkit-sticky;
    position: sticky;
    top: 2em;
  }

  .content {
    padding: 2.65em 6em 0 3.5em;
  }

  .linebreak {
    display: block;
  }

}



@media screen and (min-width: 100em) {

  :root {
    --type-base: 2.75em;
  }

  .wb {
    max-width: 250rem;
  }

}



@media print {

  :root {
    --type-base: 1.5em;
  }

  h1 {
    margin: 0;
  }

  img {
    display: block;
    max-height: 25em;
    margin: 0 auto;
  }

  .hidden-print {
    display: none !important;
  }

}



@media(prefers-color-scheme: dark) {

  :root {
    --color-text: 255, 255, 255;
    --color-background: 0, 0, 0;
    --color-link: 255, 255, 255;
  }

}