:root {
  --color-bg: #ffffff;
  --color-text: #111111;
  --color-accent: #d60000;
  --color-muted: #888888;
  --color-border: #000000;
  --color-surface: #f6f6f6;

  --size-brevier: 8pt;
  --size-bourgeois: 9pt;
  --size-long-primer: 10pt;
  --size-small-pica: 11pt;
  --size-pica: 12pt;
  --size-english: 14pt;
  --size-great-primer: 18pt;
  --size-paragon: 20pt;
  --size-double-small-pica: 22pt;
  --size-double-pica: 24pt;
  --size-double-english: 28pt;
  --size-double-great-primer: 36pt;

  --font-family-base: "Primer", system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  --font-family-index: "index", sans-serif;
  --font-family-lorien: "Lorien", serif;
  --font-family-mrs-eaves: "Mrs Eaves", serif;
  --font-family-bembo: "Bembo", serif;
  --font-family-bodoni: "Bodoni", serif;
  --font-family-ionic: "Ionic", serif;
  --font-family-gill-sans-shadowed: "Gill Sans Shadowed", sans-serif;

  --page-max-width: 1120px;
  --text-max-width: 52rem;
  --page-gutter: clamp(1rem, 3vw, 2rem);
  --lesson-header-height: 5.25rem;
  --section-gap: 1rem;
}

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

@font-face {
  font-family: "MDUI";
  src: url("fonts/MDUI-VF.woff2") format("woff2");
  font-weight: 100 900;
  font-style: normal;
  font-display: swap;
}

@font-face {
  font-family: "Primer";
  src: url("fonts/primer-light.woff2") format("woff2");
  font-weight: 300;
  font-style: normal;
  font-display: swap;
}

@font-face {
  font-family: "Primer";
  src: url("fonts/primer-light-italic.woff2") format("woff2");
  font-weight: 300;
  font-style: italic;
  font-display: swap;
}

@font-face {
  font-family: "Primer";
  src: url("fonts/primer-regular.woff2") format("woff2");
  font-weight: 400;
  font-style: normal;
  font-display: swap;
}

@font-face {
  font-family: "Primer";
  src: url("fonts/primer-regular-italic.woff2") format("woff2");
  font-weight: 400;
  font-style: italic;
  font-display: swap;
}

@font-face {
  font-family: "Primer";
  src: url("fonts/primer-medium.woff2") format("woff2");
  font-weight: 500;
  font-style: normal;
  font-display: swap;
}

@font-face {
  font-family: "Primer";
  src: url("fonts/primer-medium-italic.woff2") format("woff2");
  font-weight: 500;
  font-style: italic;
  font-display: swap;
}

@font-face {
  font-family: "Primer";
  src: url("fonts/primer-semibold.woff2") format("woff2");
  font-weight: 600;
  font-style: normal;
  font-display: swap;
}

@font-face {
  font-family: "Primer";
  src: url("fonts/primer-semibold-italic.woff2") format("woff2");
  font-weight: 600;
  font-style: italic;
  font-display: swap;
}

@font-face {
  font-family: "Primer";
  src: url("fonts/primer-bold.woff2") format("woff2");
  font-weight: 700;
  font-style: normal;
  font-display: swap;
}

@font-face {
  font-family: "Primer";
  src: url("fonts/primer-bold-italic.woff2") format("woff2");
  font-weight: 700;
  font-style: italic;
  font-display: swap;
}

@font-face {
  font-family: "index";
  src: url("fonts/index.woff2") format("woff2");
  font-weight: 350;
  font-style: normal;
  font-display: swap;
}

@font-face {
  font-family: "Lorien";
  src: url("fonts/lorien-book.woff2") format("woff2");
  font-weight: 350;
  font-style: normal;
  font-display: swap;
}

@font-face {
  font-family: "Mrs Eaves";
  src: url("fonts/mrseaves.woff2") format("woff2");
  font-weight: 400;
  font-style: normal;
  font-display: swap;
}

@font-face {
  font-family: "Bembo";
  src: url("fonts/bembo.woff2") format("woff2");
  font-weight: 400;
  font-style: normal;
  font-display: swap;
}

@font-face {
  font-family: "Bodoni";
  src: url("fonts/bodoni-regular.woff2") format("woff2");
  font-weight: 400;
  font-style: normal;
  font-display: swap;
}

@font-face {
  font-family: "Bodoni";
  src: url("fonts/bodoni-bold.woff2") format("woff2");
  font-weight: 700;
  font-style: normal;
  font-display: swap;
}

@font-face {
  font-family: "Ionic";
  src: url("fonts/ionic.woff2") format("woff2");
  font-weight: 400;
  font-style: normal;
  font-display: swap;
}

@font-face {
  font-family: "Gill Sans Shadowed";
  src: url("fonts/gillsansshadowed.woff2") format("woff2");
  font-weight: 400;
  font-style: normal;
  font-display: swap;
}

@font-face {
  font-family: "Lorien";
  src: url("fonts/lorien-book-italic.woff2") format("woff2");
  font-weight: 350;
  font-style: italic;
  font-display: swap;
}

@font-face {
  font-family: "Lorien";
  src: url("fonts/lorien-regular.woff2") format("woff2");
  font-weight: 400;
  font-style: normal;
  font-display: swap;
}

@font-face {
  font-family: "Lorien";
  src: url("fonts/lorien-regular-italic.woff2") format("woff2");
  font-weight: 400;
  font-style: italic;
  font-display: swap;
}

@font-face {
  font-family: "Lorien";
  src: url("fonts/lorien-semibold.woff2") format("woff2");
  font-weight: 600;
  font-style: normal;
  font-display: swap;
}

@font-face {
  font-family: "Lorien";
  src: url("fonts/lorien-semibold-italic.woff2") format("woff2");
  font-weight: 600;
  font-style: italic;
  font-display: swap;
}

@font-face {
  font-family: "Lorien";
  src: url("fonts/lorien-bold.woff2") format("woff2");
  font-weight: 700;
  font-style: normal;
  font-display: swap;
}

@font-face {
  font-family: "Lorien";
  src: url("fonts/lorien-bold-italic.woff2") format("woff2");
  font-weight: 700;
  font-style: italic;
  font-display: swap;
}

@font-face {
  font-family: "Lorien";
  src: url("fonts/lorien-black.woff2") format("woff2");
  font-weight: 900;
  font-style: normal;
  font-display: swap;
}

@font-face {
  font-family: "Lorien";
  src: url("fonts/lorien-black-italic.woff2") format("woff2");
  font-weight: 900;
  font-style: italic;
  font-display: swap;
}

html,
body {
  margin: 0;
  padding: 0;
  min-height: 100%;
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-family-base);
  font-weight: 400;
  font-size: var(--size-pica);
  line-height: 1.5;
  color: var(--color-text);
  background: var(--color-bg);
}

i,
em {
  font-style: italic;
}

button,
select,
input,
textarea {
  font: inherit;
}

.course {
  width: 100%;
}

.intro {
  padding: clamp(2rem, 6vw, 5rem) var(--page-gutter) clamp(2rem, 4vw, 3rem);
}

.intro__inner {
  max-width: var(--page-max-width);
  margin: 0 auto;
}

.topic-intro {
  padding-block: 2.5rem 1.5rem;
  padding-inline: var(--page-gutter);
}

.content-inner {
  max-width: var(--page-max-width);
  margin-inline: auto;
}

.intro__text {
  width: min(100%, 40rem);
  margin: 0 auto 2rem;
  font-weight: 300;
  font-size: 2rem;
  line-height: 1.45;
  color: var(--color-text);
}

.intro__text--with-arrow {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  column-gap: 0.5rem;
  align-items: start;
}

.intro__arrow {
  font-family: var(--font-family-index);
  font-size: 1em;
  line-height: 1.45;
  display: inline-block;
  transform: translateX(-0.9em);
}

.intro__text-content {
  display: block;
}

.lesson-group-title {
  width: min(calc(100% - (var(--page-gutter) * 2)), 400px);
  margin: 0 auto;
  padding: 6rem 0 2rem;
  font-size: clamp(1.15rem, 2vw, 1.5rem);
  line-height: 1.1;
  font-weight: 600;
  text-align: left;
  transform: translateX(-1.625rem);
}

.intro + .lesson-group-title {
  padding-top: 6rem;
}

.topic-intro__lead,
.section-text {
  max-width: 40rem;
  margin: 0;
  font-size: var(--size-english);
  line-height: 1.45;
  color: var(--color-text);
}

.section-text + .section-text,
.section-text + .exercise-block + .section-text,
.exercise-block + .section-text {
  text-indent: 54px;
}

.lesson {
  border-bottom: 1px solid var(--color-border);
  background: var(--color-bg);
  position: relative;
}

.lesson.is-locked .lesson__toggle,
.homework.is-locked .homework__button {
  cursor: default;
}

.lesson.is-locked {
  border-bottom-color: var(--color-muted);
}

.lesson-group-title.is-locked + .lesson.is-locked {
  border-top-color: var(--color-muted);
}

.lesson.is-locked .lesson__title,
.lesson-group-title.is-locked {
  color: var(--color-muted);
}

.homework.is-locked .homework__button {
  border-color: var(--color-muted);
  color: var(--color-muted);
  box-shadow: none;
}

.lesson-group-title + .lesson {
  border-top: 1px solid var(--color-border);
}

.homework {
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
  justify-content: center;
  padding: 3rem var(--page-gutter);
}

.exercise {
  display: flex;
  justify-content: center;
  padding-top: 2rem;
}

.homework__button {
  appearance: none;
  border: 1px solid var(--color-border);
  border-radius: 999px;
  background: var(--color-bg);
  color: var(--color-text);
  padding: 0.75rem 1.5rem;
  min-width: 10rem;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.45rem;
  font: inherit;
  font-size: clamp(1.15rem, 2vw, 1.5rem);
  font-variant-numeric: tabular-nums;
  line-height: 1.1;
  cursor: pointer;
  box-shadow: 0 0.2rem 0 rgba(0, 0, 0, 0.12);
  transition:
    transform 160ms ease,
    box-shadow 160ms ease;
}

.homework__arrow {
  font-family: var(--font-family-index);
  line-height: 1;
}

.homework__button:not(:disabled):hover,
.homework__button:not(:disabled):focus-visible {
  outline: none;
  transform: translateY(-0.08rem);
  box-shadow: 0 0.32rem 0 rgba(0, 0, 0, 0.16);
}

.homework-popover {
  width: min(calc(100vw - (var(--page-gutter) * 2)), 38rem);
  max-height: min(84vh, 48rem);
  border: 1px solid var(--color-border);
  border-radius: 8px;
  padding: 0;
  background: var(--color-bg);
  color: var(--color-text);
  box-shadow: 0 1.25rem 4rem rgba(0, 0, 0, 0.22);
}

.homework-popover::backdrop {
  background: rgba(255, 255, 255, 0.72);
  backdrop-filter: blur(6px);
  -webkit-backdrop-filter: blur(6px);
}

.homework-popover__form {
  position: relative;
  display: flex;
  flex-direction: column;
  gap: 0;
  padding: 2rem;
  max-height: inherit;
  overflow: auto;
}

.homework-popover .section-title {
  margin-bottom: 1rem;
}

.recommendations-image {
  display: block;
  width: 100%;
  margin: 1rem 0 1.5rem;
  border: 1px solid var(--color-border);
}

.homework-copybox {
  width: 100%;
  min-height: 16rem;
  margin: 1rem 0;
  padding: 1rem;
  border: 1px solid var(--color-border);
  border-radius: 0;
  background: var(--color-bg);
  color: var(--color-text);
  resize: vertical;
  font: inherit;
  font-size: var(--size-pica);
  line-height: 1.45;
}

.homework-popover__close {
  appearance: none;
  position: absolute;
  top: 0.75rem;
  right: 0.75rem;
  width: 2rem;
  height: 2rem;
  border: 0;
  border-radius: 50%;
  background: transparent;
  color: var(--color-text);
  font: inherit;
  font-size: 1.5rem;
  line-height: 1;
  cursor: pointer;
}

.homework-popover__close:hover,
.homework-popover__close:focus-visible {
  outline: none;
  background: rgba(0, 0, 0, 0.08);
}

.lesson.is-open {
  position: fixed;
  inset: 0;
  z-index: 1000;
  border-bottom: 0;
  display: flex;
  flex-direction: column;
  background: var(--color-bg);
}

.lesson__header {
  position: sticky;
  top: 0;
  z-index: 20;
  min-height: var(--lesson-header-height);
  display: block;
  align-items: stretch;
  background: rgba(255, 255, 255, 0.96);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  flex: 0 0 auto;
  transform-origin: top center;
  will-change: transform;
}

.lesson__panel {
  display: none;
}

.lesson.is-open .lesson__panel {
  display: block;
  flex: 1 1 auto;
  min-height: 0;
}

.lesson__panel-inner {
  height: calc(100vh - var(--lesson-header-height));
  overflow-y: auto;
  overflow-x: hidden;
  padding-inline: var(--page-gutter);
  background: var(--color-bg);
}

.lesson.is-open .lesson__panel-inner {
  height: calc(100vh - var(--lesson-header-height));
}

.lesson__toggle {
  appearance: none;
  border: 0;
  background: transparent;
  width: 100%;
  min-height: var(--lesson-header-height);
  padding: 1rem calc(var(--page-gutter) + 3.25rem) 1rem var(--page-gutter);
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: left;
  cursor: pointer;
  position: relative;
  font-variant-numeric: tabular-nums;
  transition: padding 220ms ease, justify-content 220ms ease;
}

.lesson__toggle:hover,
.lesson__toggle:focus-visible {
  outline: none;
  background: rgba(0, 0, 0, 0.015);
}

.lesson.is-locked .lesson__toggle:hover,
.lesson.is-locked .lesson__toggle:focus-visible {
  background: transparent;
}

.lesson__toggle::after {
  content: "\2193";
  position: absolute;
  top: 50%;
  right: max(var(--page-gutter), calc(50% - 200px));
  transform: translateY(-50%) rotate(0deg);
  transform-origin: center;
  font-family: var(--font-family-index);
  font-size: 1.25rem;
  line-height: 1;
  pointer-events: none;
  transition:
    right 220ms ease,
    transform 220ms ease;
}

.lesson.is-open .lesson__toggle {
  justify-content: flex-start;
  border-bottom: 1px solid var(--color-border);
}

.lesson.is-open .lesson__toggle::after {
  right: var(--page-gutter);
  transform: translateY(-50%) rotate(-180deg);
}

.lesson__title {
  width: min(100%, 400px);
  margin: 0 auto;
  font-size: clamp(1.15rem, 2vw, 1.5rem);
  line-height: 1.1;
  transition:
    width 220ms ease,
    max-width 220ms ease,
    margin 220ms ease;
}

.lesson.is-open .lesson__title {
  width: 100%;
  max-width: none;
  margin: 0;
}

.lesson__close {
  appearance: none;
  border: 0;
  background: transparent;
  min-width: 4.5rem;
  padding: 0 1rem;
  display: none;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  color: var(--color-text);
  font-size: 2rem;
  line-height: 1;
}

.lesson.is-open .lesson__close {
  display: inline-flex;
}

.lesson__close:hover,
.lesson__close:focus-visible {
  outline: none;
  color: var(--color-accent);
}

.lesson__panel-inner > * {
  max-width: var(--page-max-width);
  margin-inline: auto;
}

.topic-section {
  padding-block: 2.5rem;
}

.placeholder-section {
  min-height: calc(100vh - var(--lesson-header-height));
  display: flex;
  flex-direction: column;
  justify-content: center;
  padding-block: 4rem;
}

.text-column-section .section-title,
.text-column-section .section-text {
  width: min(100%, 40rem);
  margin-inline: auto;
}

.white-space-stage {
  position: relative;
  min-height: 260vh;
}

.white-space-stage__interactive {
  position: sticky;
  top: 0;
  height: var(--white-space-scrollport-height, calc(100vh - var(--lesson-header-height)));
  min-height: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--color-bg);
  z-index: 0;
}

.white-space-controls {
  position: absolute;
  top: 1.5rem;
  left: var(--page-gutter);
  right: var(--page-gutter);
  z-index: 2;
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  justify-content: center;
}

.white-space-instruction {
  width: min(100%, 40rem);
  margin: 0 auto;
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  column-gap: 0.5rem;
  font-size: var(--size-english);
  line-height: 1.45;
}

.exercise-block {
  margin-top: 2rem;
  padding-top: 1rem;
  border-top: 1px solid var(--color-border);
}

.white-space-instruction__arrow {
  font-family: var(--font-family-index);
  line-height: 1.45;
  transform: translateX(-0.9em);
}

.white-space-stage__content {
  position: relative;
  z-index: 1;
  pointer-events: none;
}

.white-space-interactive__canvas {
  display: block;
  width: 100%;
  height: min(76vh, 44rem);
  margin-top: 3rem;
  cursor: crosshair;
  transition: filter 260ms ease;
}

.white-space-stage.is-grey-value .white-space-interactive__canvas {
  filter: blur(10px);
}

.white-space-topic {
  min-height: 100vh;
  padding-block: 4rem;
  display: flex;
  flex-direction: column;
  justify-content: center;
  background: var(--color-bg);
  cursor: text;
}

.white-space-filter-reveal {
  min-height: var(--white-space-scrollport-height, calc(100vh - var(--lesson-header-height)));
}

.measure-section {
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
  padding-block: 4rem;
}

.measure-section .section-title:not(:first-child) {
  margin-top: 2rem;
}

.measure-section .section-title,
.measure-section .section-text {
  width: min(100%, 40rem);
  margin-inline: auto;
}

.measure-block {
  align-self: center;
  width: min(100%, 34rem);
  margin-block: 0.75rem;
  text-align: center;
  font-size: var(--size-english);
  line-height: 1.45;
}

.measure-block p {
  margin: 0;
}

.point-comparison-canvas {
  display: block;
  width: 100%;
  height: clamp(14rem, 34vh, 22rem);
  margin-block: 0.75rem 1.5rem;
}

.cicero-interactive {
  width: 100%;
  margin-top: 0.75rem;
}

.cicero-interactive__meta {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem 2rem;
  justify-content: center;
  margin-bottom: 1rem;
  font-size: var(--size-bourgeois);
  text-align: center;
}

.cicero-interactive__meta b {
  font-weight: 600;
}

.cicero-interactive__canvas {
  display: block;
  width: 100%;
  height: clamp(26rem, 62vh, 42rem);
  border: 1px solid var(--color-border);
  background: var(--color-bg);
  cursor: crosshair;
}

.glossary-section {
  padding-block: 4rem;
}

.glossary-table {
  width: 100%;
  margin-top: 2rem;
  border-collapse: collapse;
  font-size: var(--size-pica);
  line-height: 1.35;
}

.glossary-table th,
.glossary-table td {
  padding: 0.65rem 0.75rem 0.65rem 0;
  border-bottom: 1px solid rgba(0, 0, 0, 0.18);
  text-align: left;
  vertical-align: top;
}

.glossary-table th {
  position: sticky;
  top: 0;
  z-index: 1;
  background: var(--color-bg);
  font-weight: 600;
}

.glossary-sort-button {
  appearance: none;
  border: 0;
  background: transparent;
  color: inherit;
  padding: 0;
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  font: inherit;
  font-weight: inherit;
  font-variant-numeric: tabular-nums;
  cursor: pointer;
}

.glossary-sort-button:focus-visible {
  outline: 1px solid var(--color-border);
  outline-offset: 0.2rem;
}

.glossary-sort-button__arrow {
  display: inline-block;
  font-family: var(--font-family-index);
  line-height: 1;
  opacity: 0;
  transform: rotate(90deg);
  transform-origin: center;
}

.glossary-sort-button.is-active .glossary-sort-button__arrow {
  opacity: 1;
}

.glossary-sort-button:not(.is-active):hover .glossary-sort-button__arrow,
.glossary-sort-button:not(.is-active):focus-visible .glossary-sort-button__arrow {
  opacity: 0.75;
}

.glossary-table th:nth-child(1),
.glossary-table th:nth-child(2),
.glossary-table td:nth-child(1),
.glossary-table td:nth-child(2) {
  width: 22%;
}

.glossary-term {
  border-bottom: 1px dotted currentColor;
  cursor: help;
  pointer-events: auto;
}

.glossary-tooltip {
  position: fixed;
  z-index: 2147483647;
  max-width: min(24rem, calc(100vw - 2rem));
  padding: 0.55rem 0.7rem;
  border: 1px solid var(--color-border);
  background: var(--color-bg);
  color: var(--color-text);
  font-size: 0.86rem;
  line-height: 1.25;
  opacity: 0;
  pointer-events: none;
  transform: translateY(0.2rem);
  transition: opacity 100ms ease, transform 100ms ease;
}

.glossary-tooltip.is-visible {
  opacity: 1;
  transform: translateY(0);
}

.section-title {
  margin: 0;
  font-size: var(--size-english);
  line-height: 1.45;
  font-weight: 600;
}

.full-screen-interactive {
  min-height: 100vh;
  display: flex;
  align-items: center;
}

.full-screen-interactive__inner {
  width: 100%;
  max-width: var(--page-max-width);
  margin-inline: auto;
}

.macro-stage {
  position: relative;
  margin-top: 2rem;
}

.macro-stage__interactive {
  position: sticky;
  top: 0;
  height: var(--macro-scrollport-height, calc(100vh - var(--lesson-header-height)));
  min-height: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 0;
  background: var(--color-bg);
}

.macro-stage__content {
  position: relative;
  z-index: 1;
  pointer-events: none;
}

.macro-topic {
  min-height: 60vh;
  padding-block: 4rem;
  padding-inline: var(--page-gutter);
  background: #ffffff;
  display: flex;
  align-items: flex-end;
  cursor: text;
}

.macro-topic__inner {
  max-width: var(--page-max-width);
  width: 100%;
  margin-inline: auto;
}

.macro-topic .section-title,
.macro-topic .section-text {
  width: min(100%, 40rem);
  margin-inline: auto;
}

.macro-reveal {
  min-height: 120vh;
  background: transparent;
}

.macro-interactive {
  position: relative;
  width: 100%;
  max-width: var(--page-max-width);
  margin-inline: auto;
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
  pointer-events: auto;
}

.macro-interactive[data-macro-mode="space"] .macro-interactive__controls,
.macro-interactive[data-macro-mode="pages"] .macro-interactive__controls,
.macro-interactive[data-macro-mode="press-sheets"] .macro-interactive__controls {
  position: absolute;
  z-index: 2;
  top: 1.5rem;
  left: 0;
  right: 0;
}

.macro-interactive[data-macro-mode="space"] .macro-interactive__canvas,
.macro-interactive[data-macro-mode="pages"] .macro-interactive__canvas,
.macro-interactive[data-macro-mode="press-sheets"] .macro-interactive__canvas {
  padding-top: 4.5rem;
}

.macro-interactive[data-macro-mode="space"],
.macro-interactive[data-macro-mode="pages"],
.macro-interactive[data-macro-mode="press-sheets"] {
  height: 100%;
  justify-content: center;
}

.macro-interactive[data-macro-mode="pages"] .macro-interactive__canvas,
.macro-interactive[data-macro-mode="press-sheets"] .macro-interactive__canvas {
  height: 100%;
  min-height: 0;
  overflow: hidden;
}

.macro-interactive__controls {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem 2rem;
  align-items: center;
  justify-content: center;
  font-size: var(--size-bourgeois);
  padding-inline: var(--page-gutter);
}

.macro-controls {
  display: none;
  flex-wrap: wrap;
  gap: 0.75rem 1.25rem;
  align-items: center;
  justify-content: center;
  text-align: center;
}

.macro-controls.is-active {
  display: flex;
}

.macro-controls__group {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  align-items: center;
  justify-content: center;
}

.macro-controls__group--margins {
  gap: 0.75rem;
}

.macro-controls__label {
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  font-size: var(--size-brevier);
}

.macro-controls__button {
  border: 1px solid var(--color-border);
  background: #ffffff;
  border-radius: 999px;
  padding: 0.25rem 0.75rem;
  font: inherit;
  font-size: var(--size-bourgeois);
  font-variant-numeric: tabular-nums;
  cursor: pointer;
  text-transform: uppercase;
  letter-spacing: 0.08em;
}

.macro-controls__button:hover,
.macro-controls__button:focus-visible {
  border-color: var(--color-text);
  outline: none;
}

.macro-controls__button.is-active {
  border-color: var(--color-accent);
  background-color: var(--color-accent);
  color: #ffffff;
}

.macro-controls__button:disabled,
.macro-controls__button[aria-disabled="true"] {
  border-color: var(--color-muted);
  color: var(--color-muted);
  background: var(--color-bg);
  cursor: default;
}

.macro-controls__select {
  min-width: 9rem;
  padding: 0.25rem 0.75rem;
  border-radius: 999px;
  border: 1px solid var(--color-border);
  background: #ffffff;
  font: inherit;
  font-size: var(--size-bourgeois);
  cursor: pointer;
}

.macro-controls__select:focus {
  outline: none;
  border-color: var(--color-accent);
}

.macro-checkbox {
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
  font-size: var(--size-bourgeois);
  cursor: pointer;
}

.macro-checkbox input {
  width: 1rem;
  height: 1rem;
  margin: 0;
  accent-color: var(--color-text);
}

.macro-controls__counter {
  flex-basis: 100%;
  text-align: center;
  font-size: var(--size-bourgeois);
}

.macro-interactive__canvas {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 2rem;
  padding-inline: var(--page-gutter);
  min-height: 32rem;
}

.macro-interactive__canvas--spread {
  gap: 0;
}

.macro-interactive__summary {
  margin-top: -0.25rem;
  text-align: center;
  font-size: var(--size-bourgeois);
  color: var(--color-text);
  min-height: 1.5em;
}

.macro-interactive__hint {
  display: none;
}

.macro-stepper {
  display: inline-flex;
  align-items: center;
  border: 1px solid var(--color-border);
  border-radius: 999px;
  overflow: hidden;
  background: #ffffff;
}

.macro-stepper__button {
  appearance: none;
  border: 0;
  background: transparent;
  min-width: 2.5rem;
  height: 2.25rem;
  font: inherit;
  font-variant-numeric: tabular-nums;
  cursor: pointer;
}

.macro-stepper__button:hover,
.macro-stepper__button:focus-visible {
  outline: none;
  background: rgba(0, 0, 0, 0.04);
}

.macro-stepper__input {
  width: 4rem;
  height: 2.25rem;
  border: 0;
  border-left: 1px solid var(--color-border);
  border-right: 1px solid var(--color-border);
  text-align: center;
  font: inherit;
  font-variant-numeric: tabular-nums;
  background: transparent;
  appearance: textfield;
  -moz-appearance: textfield;
}

.macro-stepper__input::-webkit-outer-spin-button,
.macro-stepper__input::-webkit-inner-spin-button {
  -webkit-appearance: none;
  margin: 0;
}

.space-pages-overview {
  width: 100%;
  max-width: 100%;
  display: grid;
  gap: var(--space-pages-gap, 0.65rem);
  justify-content: center;
  justify-items: center;
  align-items: start;
}

.space-pages-overview--single {
  grid-template-columns: repeat(auto-fit, var(--space-page-thumb-width, 4.75rem));
}

.space-pages-overview--spread {
  grid-template-columns: repeat(auto-fit, var(--space-spread-width, 9.5rem));
}

.space-pages-overview__spread {
  display: grid;
  grid-template-columns: repeat(2, var(--space-page-thumb-width, 4.75rem));
  gap: 0;
  align-items: start;
  justify-content: center;
}

.space-pages-overview__spread > .space-page-thumb + .space-page-thumb {
  margin-left: -1px;
}

.space-page-thumb {
  aspect-ratio: var(--space-page-ratio, 1 / 1.414);
  border: 1px solid var(--color-border);
  background: #ffffff;
  border-radius: 0;
  position: relative;
  width: 100%;
  max-width: var(--space-page-thumb-width, 5rem);
  min-height: 0;
}

.space-page-thumb--single {
  max-width: var(--space-page-thumb-width, 4.75rem);
}

.space-page-thumb--ghost {
  visibility: hidden;
}

.space-page-thumb__label {
  position: absolute;
  left: 0.4rem;
  bottom: 0.35rem;
  font-size: 0.72rem;
  line-height: 1;
  color: var(--color-muted);
}

.space-sheet-stack {
  width: 100%;
  max-width: 100%;
  display: grid;
  grid-template-columns: repeat(var(--space-sheet-columns, auto-fit), var(--space-sheet-item-width, 14rem));
  gap: var(--space-sheet-gap, 1rem);
  justify-content: center;
  align-items: start;
}

.space-sheet-row {
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
  align-items: center;
}

.space-sheet-row__sheets {
  display: flex;
  gap: var(--space-sheet-inner-gap, 0.75rem);
  align-items: flex-start;
  justify-content: center;
}

.space-sheet {
  width: var(--space-sheet-width, 12rem);
  max-width: none;
  aspect-ratio: var(--sheet-ratio, 1 / 1.414);
  border: 1px solid var(--color-border);
  background: #ffffff;
  position: relative;
  overflow: hidden;
}

.space-sheet__leaf {
  position: absolute;
  border: 1px solid var(--color-accent);
  background: #ffffff;
  box-sizing: border-box;
}

.space-sheet__sheet-label {
  position: absolute;
  left: 50%;
  top: 50%;
  z-index: 2;
  transform: translate(-50%, -50%);
  padding: 0.28rem 0.65rem;
  border-radius: 999px;
  background: var(--color-accent);
  color: #ffffff;
  font-size: var(--size-bourgeois);
  line-height: 1;
  font-variant-numeric: tabular-nums;
  white-space: nowrap;
}

.space-sheet__leaf-label {
  position: absolute;
  left: 0.28rem;
  bottom: 0.24rem;
  font-size: 0.64rem;
  line-height: 1;
  color: var(--color-text);
}

@media (max-width: 800px) {
  .space-sheet-row {
    grid-template-columns: 1fr;
    gap: 0.4rem;
  }

  .space-sheet-row__label {
    padding-top: 0;
  }
}

.macro-page {
  position: relative;
  background-color: #ffffff;
  box-shadow: none;
  border-radius: 2px;
  border: 1px solid var(--color-border);
  aspect-ratio: 1 / 1.414;
  width: min(60vw, 26rem);
  overflow: hidden;
}

.macro-page__content {
  position: absolute;
  inset: 10% 10% 10% 10%;
  background: transparent;
}

.macro-page__margin {
  position: absolute;
  background: rgba(214, 0, 0, 0.06);
  pointer-events: none;
  opacity: 0;
}

.macro-page__margin--top {
  left: 0;
  right: 0;
  top: 0;
}

.macro-page__margin--bottom {
  left: 0;
  right: 0;
  bottom: 0;
}

.macro-page__margin--left {
  top: 0;
  bottom: 0;
  left: 0;
}

.macro-page__margin--right {
  top: 0;
  bottom: 0;
  right: 0;
}

.macro-page__columns {
  position: absolute;
  inset: 0;
  opacity: 0;
  pointer-events: none;
}

.macro-page__column {
  position: absolute;
  top: 0;
  bottom: 0;
  box-sizing: border-box;
}

.macro-page__gutter {
  position: absolute;
  top: 0;
  bottom: 0;
  background: rgba(214, 0, 0, 0.06);
  pointer-events: none;
}

.macro-page__baselines {
  position: absolute;
  inset: 0;
  pointer-events: none;
  opacity: 0;
}

.macro-page__baseline {
  position: absolute;
  left: 0;
  right: 0;
  height: 1px;
  background: rgba(0, 0, 0, 0.08);
}

.macro-page__modules {
  position: absolute;
  inset: 0;
  pointer-events: none;
  opacity: 0;
  background: rgba(214, 0, 0, 0.06);
}

.macro-page__module {
  position: absolute;
  background: #ffffff;
}

.macro-page__module-line {
  position: absolute;
  background: var(--color-accent);
}

.macro-page__module-line--vertical {
  top: 0;
  bottom: 0;
  width: 1px;
}

.macro-page__module-line--horizontal {
  left: 0;
  right: 0;
  height: 1px;
}

.hierarchy-stage {
  position: relative;
  min-height: 420vh;
}

.hierarchy-stage__interactive {
  position: sticky;
  top: 0;
  height: var(--hierarchy-scrollport-height, calc(100vh - var(--lesson-header-height)));
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--color-bg);
  z-index: 0;
}

.hierarchy-stage__content {
  position: relative;
  z-index: 1;
  pointer-events: none;
}

.hierarchy-canvas {
  position: relative;
  width: 100%;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 4.5rem var(--page-gutter) 2rem;
  pointer-events: auto;
}

.hierarchy-controls {
  position: absolute;
  top: 1.5rem;
  left: var(--page-gutter);
  right: var(--page-gutter);
  display: none;
  flex-wrap: wrap;
  gap: 0.75rem;
  justify-content: center;
  z-index: 2;
}

.hierarchy-stage[data-hierarchy-mode="separation"] .hierarchy-controls {
  display: flex;
}

.hierarchy-page {
  width: min(72vw, 23rem);
  aspect-ratio: 110 / 178;
  border: 1px solid var(--color-border);
  background: #ffffff;
  overflow: hidden;
  padding: 2.2rem 1.65rem;
  font-size: clamp(0.62rem, 1.15vw, 0.88rem);
  line-height: 1.28;
  color: var(--color-text);
}

.hierarchy-page__paragraph {
  margin: 0;
}

.hierarchy-page__text {
  margin: 0;
}

.hierarchy-page__content {
  overflow: hidden;
}

.hierarchy-size-layout {
  height: 100%;
  display: flex;
  flex-direction: column;
  overflow: hidden;
}

.hierarchy-size-body {
  flex: 1 1 auto;
  min-height: 0;
  overflow: hidden;
}

.hierarchy-size-title {
  margin: 0 0 0.75rem;
  font-size: 2.35em;
  line-height: 0.96;
  font-weight: 600;
}

.hierarchy-size-subtitle {
  margin: 1.2rem 0 0.3rem;
  font-size: 1.18em;
  line-height: 1.05;
  font-weight: 600;
}

.hierarchy-size-footnote {
  flex: 0 0 auto;
  margin: 0.8rem 0 0;
  padding-top: 0.8rem;
  font-size: 0.72em;
  line-height: 1.22;
  display: grid;
  grid-template-columns: 1.5em 1fr;
  column-gap: 0;
}

.hierarchy-size-footnote sup {
  justify-self: start;
}

.hierarchy-stage[data-hierarchy-mode="size"] .hierarchy-page:hover .hierarchy-size-title,
.hierarchy-stage[data-hierarchy-mode="size"] .hierarchy-page:hover .hierarchy-size-subtitle {
  margin: 0;
  font-size: 1em;
  line-height: inherit;
  font-weight: inherit;
}

.hierarchy-stage[data-hierarchy-mode="size"] .hierarchy-page:hover .hierarchy-size-footnote {
  font-size: 1em;
  line-height: inherit;
}

.hierarchy-topic {
  min-height: 100vh;
  padding-block: 4rem;
  display: flex;
  flex-direction: column;
  justify-content: center;
  background: var(--color-bg);
  cursor: text;
}

.hierarchy-reveal {
  min-height: 100vh;
}

.hierarchy-followup {
  min-height: calc(100vh - var(--lesson-header-height));
  display: flex;
  flex-direction: column;
  justify-content: center;
  padding-block: 4rem;
}

.choice-demo {
  min-height: calc(100vh - var(--lesson-header-height));
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 1.5rem;
  padding-block: 4rem;
}

.choice-introduction {
  min-height: calc(100vh - var(--lesson-header-height));
  display: flex;
  flex-direction: column;
  justify-content: center;
  padding-block: 4rem;
}

.choice-type-comparison {
  min-height: calc(100vh - var(--lesson-header-height));
  width: min(100%, 54rem);
  margin-inline: auto;
  padding-block: 4rem;
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: 2rem;
}

.choice-type-comparison__row {
  display: grid;
  grid-template-columns: 9.5rem minmax(0, 1fr);
  gap: 1.25rem;
  align-items: baseline;
}

.choice-type-comparison__label {
  font-size: 0.82rem;
  line-height: 1.15;
  color: var(--color-muted);
}

.choice-type-comparison__sample {
  margin: 0;
}

.choice-type-comparison__sample--display {
  font-family: var(--font-family-gill-sans-shadowed);
  font-size: clamp(3.4rem, 8vw, 6rem);
  line-height: 0.95;
}

.choice-type-comparison__sample--text {
  max-width: 27rem;
  font-family: var(--font-family-primer);
  font-size: 12pt;
  line-height: 1.35;
}

.multilingual-samples {
  width: min(100%, 40rem);
  margin: 2.5rem auto 0;
  display: flex;
  flex-direction: column;
  gap: 0.9rem;
}

.multilingual-samples__row {
  display: grid;
  grid-template-columns: 9.5rem minmax(0, 1fr);
  gap: 1.25rem;
  align-items: baseline;
}

.multilingual-samples__label {
  font-size: 0.82rem;
  line-height: 1.15;
  color: var(--color-muted);
}

.multilingual-samples__sample {
  font-family: var(--font-family-lorien);
  font-size: clamp(2.2rem, 6vw, 4rem);
  line-height: 1;
}

.choice-section-image {
  display: block;
  width: min(100%, 40rem);
  margin: 2.5rem auto 0;
  border: 1px solid var(--color-border);
}

.choice-demo__controls {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  justify-content: center;
}

.choice-demo__page {
  font-family: var(--font-family-primer);
  transition: font-family 120ms ease;
}

.choice-demo__page .hierarchy-page__content {
  height: 100%;
}

.readability-introduction {
  min-height: calc(100vh - var(--lesson-header-height));
  display: flex;
  flex-direction: column;
  justify-content: center;
  padding-block: 4rem;
}

.readability-stage {
  position: relative;
  min-height: 640vh;
}

.readability-stage__interactive {
  position: sticky;
  top: 0;
  height: var(--readability-scrollport-height, calc(100vh - var(--lesson-header-height)));
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--color-bg);
  z-index: 0;
}

.readability-stage__content {
  position: relative;
  z-index: 1;
  pointer-events: none;
}

.readability-demo {
  position: relative;
  width: 100%;
  height: 100%;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 1.5rem;
  padding: 4rem var(--page-gutter);
}

.readability-demo__controls {
  position: absolute;
  top: 1.5rem;
  left: var(--page-gutter);
  right: var(--page-gutter);
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 0.75rem;
  z-index: 2;
}

.readability-demo__button {
  cursor: pointer;
}

.readability-stage[data-readability-mode="line-length"] [data-readability-control="size"],
.readability-stage[data-readability-mode="line-length"] [data-readability-control="leading"],
.readability-stage[data-readability-mode="body-size"] [data-readability-control="leading"],
.readability-stage[data-readability-mode="optical-size"] .readability-demo__controls,
.readability-stage[data-readability-mode="tracking"] .readability-demo__controls {
  display: none;
}

.readability-demo__frame {
  width: min(100%, 54rem);
  display: flex;
  justify-content: center;
}

.readability-stage[data-readability-mode="line-length"] .readability-demo__frame {
  cursor: ew-resize;
}

.readability-stage[data-readability-mode="body-size"] .readability-demo__frame,
.readability-stage[data-readability-mode="leading"] .readability-demo__frame {
  cursor: ns-resize;
}

.readability-stage:not([data-readability-mode="line-length"]):not([data-readability-mode="body-size"]):not([data-readability-mode="leading"]) .readability-demo__frame {
  cursor: crosshair;
}

.readability-demo__text {
  width: var(--readability-width, 36rem);
  max-width: 100%;
  border-left: 3px solid var(--readability-line-color, var(--color-accent));
  border-right: 3px solid var(--readability-line-color, var(--color-accent));
  padding-inline: 1.25rem;
  font-size: var(--readability-font-size, 12pt);
  line-height: var(--readability-line-height, 1);
  text-align: left;
  transition: border-color 120ms ease;
}

.readability-demo__text p {
  margin: 0;
}

.readability-demo__text p + p {
  text-indent: 54px;
}

.readability-optical-demo,
.readability-tracking-demo {
  display: none;
  width: min(100%, 46rem);
}

.readability-stage[data-readability-mode="optical-size"] .readability-demo__text,
.readability-stage[data-readability-mode="tracking"] .readability-demo__text {
  display: none;
}

.readability-stage[data-readability-mode="optical-size"] .readability-optical-demo,
.readability-stage[data-readability-mode="tracking"] .readability-tracking-demo {
  display: flex;
  flex-direction: column;
  gap: 1.4rem;
}

.readability-optical-demo__row,
.readability-tracking-demo__row {
  display: grid;
  grid-template-columns: 9.5rem minmax(0, 1fr);
  gap: 1.25rem;
  align-items: baseline;
}

.readability-optical-demo__label,
.readability-tracking-demo__label {
  font-size: 0.82rem;
  line-height: 1.15;
  color: var(--color-muted);
}

.readability-optical-demo__sample,
.readability-tracking-demo__sample {
  line-height: 1;
}

.readability-optical-demo__row--small-light .readability-optical-demo__sample,
.readability-optical-demo__row--small-correct .readability-optical-demo__sample {
  font-size: 9pt;
}

.readability-optical-demo__row--small-light .readability-optical-demo__sample {
  font-weight: 250;
}

.readability-optical-demo__row--small-correct .readability-optical-demo__sample {
  font-weight: 550;
}

.readability-optical-demo__row--large-heavy .readability-optical-demo__sample,
.readability-optical-demo__row--large-correct .readability-optical-demo__sample {
  font-size: clamp(4rem, 11vw, 7.5rem);
}

.readability-optical-demo__row--large-heavy .readability-optical-demo__sample {
  font-weight: 700;
}

.readability-optical-demo__row--large-correct .readability-optical-demo__sample {
  font-weight: 300;
}

.readability-tracking-demo__row--small-tight .readability-tracking-demo__sample,
.readability-tracking-demo__row--small-open .readability-tracking-demo__sample {
  font-size: 9pt;
}

.readability-tracking-demo__row--small-tight .readability-tracking-demo__sample {
  letter-spacing: -0.005em;
}

.readability-tracking-demo__row--small-open .readability-tracking-demo__sample {
  letter-spacing: 0.015em;
}

.readability-tracking-demo__row--large-open .readability-tracking-demo__sample,
.readability-tracking-demo__row--large-tight .readability-tracking-demo__sample {
  font-size: clamp(4rem, 11vw, 7.5rem);
}

.readability-tracking-demo__row--large-open .readability-tracking-demo__sample {
  letter-spacing: 0.02em;
}

.readability-tracking-demo__row--large-tight .readability-tracking-demo__sample {
  letter-spacing: -0.015em;
}

.readability-topic {
  min-height: 100vh;
  padding-block: 4rem;
  display: flex;
  flex-direction: column;
  justify-content: center;
  background: var(--color-bg);
  cursor: text;
}

.readability-reveal {
  min-height: 100vh;
}

.emphasis-demo {
  min-height: calc(100vh - var(--lesson-header-height));
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: 0.7rem;
  width: min(100%, 54rem);
  margin-inline: auto;
  padding-block: 4rem;
}

.emphasis-demo__row {
  display: grid;
  grid-template-columns: 9.5rem minmax(0, 1fr);
  gap: 1.25rem;
  align-items: baseline;
}

.emphasis-demo__label {
  font-size: 0.82rem;
  line-height: 1.15;
  color: var(--color-muted);
}

.emphasis-demo__line {
  margin: 0;
  font-family: var(--font-family-lorien);
  font-size: clamp(3.4rem, 8vw, 6rem);
  line-height: 1.02;
  font-weight: 350;
  outline: none;
  cursor: default;
}

.emphasis-demo__line--bold:hover,
.emphasis-demo__line--bold:focus-visible {
  font-weight: 700;
}

.emphasis-demo__line--italic:hover,
.emphasis-demo__line--italic:focus-visible {
  font-style: italic;
}

.emphasis-demo__line--surname:hover span,
.emphasis-demo__line--surname:focus-visible span,
.emphasis-demo__line--abbreviation:hover,
.emphasis-demo__line--abbreviation:focus-visible {
  font-variant-caps: small-caps;
  font-feature-settings: "smcp" 1;
}

.emphasis-demo__line--abbreviation:hover,
.emphasis-demo__line--abbreviation:focus-visible {
  font-variant-caps: all-small-caps;
  font-feature-settings: "smcp" 1, "c2sc" 1;
}

.emphasis-demo__line--colour:hover,
.emphasis-demo__line--colour:focus-visible {
  color: var(--color-accent);
}

@media (max-width: 900px) {
  .lesson__toggle {
    grid-template-columns: minmax(0, 1fr) auto;
    gap: 0.5rem 0.9rem;
  }
}

@media (max-width: 800px) {
  .macro-interactive__canvas {
    gap: 1.25rem;
  }

  .macro-page {
    width: min(80vw, 22rem);
  }
}

@media (max-width: 640px) {
  :root {
    --lesson-header-height: 4.75rem;
  }

  .lesson__toggle {
    padding-right: 0.75rem;
  }

  .lesson__title {
    font-size: 1.1rem;
  }

  .lesson-group-title {
    transform: none;
  }

  .glossary-table,
  .glossary-table thead,
  .glossary-table tbody,
  .glossary-table tr,
  .glossary-table th,
  .glossary-table td {
    display: block;
  }

  .glossary-table thead {
    display: none;
  }

  .glossary-table tr {
    padding-block: 0.85rem;
    border-bottom: 1px solid rgba(0, 0, 0, 0.18);
  }

  .glossary-table td {
    width: 100%;
    padding: 0.12rem 0;
    border-bottom: 0;
  }

  .glossary-table td:nth-child(1),
  .glossary-table td:nth-child(2) {
    width: 100%;
    font-weight: 600;
  }

  .glossary-table td:nth-child(1)::before {
    content: "English (UK): ";
    font-weight: 400;
  }

  .glossary-table td:nth-child(2)::before {
    content: "German: ";
    font-weight: 400;
  }

  .lesson__meta {
    font-size: var(--size-bourgeois);
  }

  .macro-topic {
    padding-block: 3rem;
  }

  .macro-interactive__controls {
    gap: 0.5rem 1.25rem;
  }

  .macro-controls__group {
    gap: 0.4rem;
  }

  .intro__text--with-arrow {
    column-gap: 0.35rem;
  }

  .intro__arrow {
    transform: translateX(-0.7em);
  }
}

body.has-open-lesson {
  overflow: hidden;
}