:root {
  --shade-1:hsl(0, 0%, 90%);
  --shade-2:hsl(0, 0%, 75%);
  --shade-3:hsl(0, 0%, 55%);
  --shade-4:hsl(0, 0%, 35%);
  --shade-5:hsl(0, 0%, 10%);

  --gap: 0.5rem;

  --brown: hsl(36, 15%, 47%);
  --brown-50: hsl(36, 28%, 68%);
  --brown-25: hsl(36, 46%, 88%);

  --blue: #5584b5;
  --blue-50: #8fb9e6;
  --blue-25: #c7dff8;

  --green: #5a9b5e;
  --green-50: #86ce8b;
  --green-25: #caf2cd;
}

@font-face {
  font-family: "Inter";
  font-weight: 400;
  src: url("../fonts/Inter-Regular.ttf");
}

@font-face {
  font-family: "Inter";
  font-weight: 600;
  src: url("../fonts/Inter-SemiBold.ttf");
}

html {
  font-size: 16px;
  font-family: 'Inter';
  background-color: white;
}

body {
  margin: auto;
  background-color: white;
}

.wall {
  box-sizing: border-box;
}

.chapter {
  box-sizing: border-box;
}

.section {
  box-sizing: border-box;
}

.section .title {
  position: sticky;
  top: 2.9rem;
}

.board {
  background-color: white;
  padding: 1rem;
  box-sizing: border-box;
  z-index: 7;
  display: none;
  max-width: 30rem;
}

.board:not(:last-child) {
  border-bottom: 1px solid rgba(0, 0, 0, 0.2);
}

.section:has(input:checked) .board {
  display: block;
}

input {
  -webkit-appearance: none;
   -moz-appearance: none;
   appearance: none;
   display: none;
}

.title {
 display: flex;
 flex-direction: column;
 justify-content: center;
 position: sticky;
 box-sizing: border-box;
}

.wall > .title {
  top: 0;
  height: 3rem;
  z-index: 10;
  background-color: inherit;
  text-align: center;
  color: white;
  font-weight: 600;
}

.chapter > .title {
  top: 3rem;
  height: 4rem;
  z-index: 9;
  position: static;
}

.section > .title {
  z-index: 8;
}

h3 span {
  display: inline-block;
  margin-left: 1.5rem;
}

.en {
  font-weight: 600;
}

.section h3:before {
  content: '▷';
  width: 1.5em;
  display: inline-block;
}

.section:has(input:checked) h3:before {
  content: '▽';
  width: 1.5em;
  display: inline-block;
}

h1, h2 {
  padding: 1rem;
}

h1 {
  font-size: 1.75rem;
}

h2 {
  font-size: 1.25rem;
}

h3 {
  font-size: 1rem;
  padding-left: 1rem;
  padding-right: 1rem;
  padding-top: 0.5rem;
  padding-bottom: 0.5rem;
  border-top: 1px solid rgba(0, 0, 0, 0.1);
  cursor: pointer;
}

h3:hover {
  opacity: 0.7;
}

h4 {
  font-size: 1.3rem;
  margin-bottom: 1.5rem;
}

p {
  line-height: 1.4;
  margin-bottom: 0.5em;
}


.wall-1 > .title {
  background-color: var(--brown);
}
.wall-1 .chapter > .title {
  background-color: var(--brown-50);
}
.wall-1 .section > .title {
  background-color: var(--brown-25);
}

.wall-2 > .title {
  background-color: var(--blue);
}
.wall-2 .chapter > .title {
  background-color: var(--blue-50);
}
.wall-2 .section > .title {
  background-color: var(--blue-25);
}

.wall-3 > .title {
  background-color: var(--green);
}
.wall-3 .chapter > .title {
  background-color: var(--green-50);
}
.wall-3 .section > .title {
  background-color: var(--green-25);
}

.captions {
  margin-top: 2rem;
}

.captions:first-child {
  margin-top: 1.5rem;
}

.caption {
  display: grid;
  grid-template-columns: 4rem auto;
  font-size: 0.9rem;
  margin-bottom: 1rem;
}

.index {
  display: flex;
  gap: 0.1rem
}

.number {
  min-width: 1.4rem;
  height: 1.4rem;
  text-align: center;
  display: flex;
  justify-content: center;
  align-items: center;
  background-color: black;
  color: white;
  font-size: 0.7rem;
  letter-spacing: 0.05em;
  font-weight: 600;
}

.dash {
  height: 1.4rem;
  margin-top: 0.13em;
}

em {
  color: rgb(139, 139, 139);
}

strong {
  font-weight: 600;
}

.quote {
  text-align: center;
  padding: 2rem;
  box-sizing: border-box;
}

blockquote {
  font-size: 1.1rem;
}

blockquote p:before {
  content: '“';
}

blockquote p:after {
  content: '”';
}

.quote figcaption {
  font-size: 0.9rem;
  color: rgb(139, 139, 139);
}

.intro {
  font-weight: 600;
  padding-top: 2rem;
  padding-bottom: 2rem;
}

.intro h1 {
  font-size: 3rem;
}

.intro h2 {
  font-size: 1.5rem;
}

.intro .text {
  font-size: 1.1rem;
  padding: 1rem;
  box-sizing: border-box;
}

footer {
  padding: 1rem;
  padding-top: 2rem;
  box-sizing: border-box;
  text-align: center;
  background-color: rgb(34, 34, 34);
  color: white;
}

footer h1,
footer h2 {
  font-weight: 600;
  font-size: 1rem;
  padding: 0;
}

footer h3 {
  font-size: 1.25rem;
}