* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: system-ui, sans-serif;
  line-height: 1.6;
  color: #172033;
  background: #f3f5f9;
}

.entete {
  padding: 2rem 1rem;
  color: white;
  background: #183b56;
  text-align: center;
}

.entete h1 {
  margin: 0;
}

.conteneur {
  width: min(100% - 2rem, 48rem);
  margin: 2rem auto;
}

.carte {
  padding: clamp(1rem, 4vw, 2rem);
  background: white;
  border-radius: 1rem;
  box-shadow: 0 0.5rem 2rem rgb(0 0 0 / 8%);
}

button {
  padding: 0.8rem 1.2rem;
  border: 0;
  border-radius: 0.5rem;
  font: inherit;
  color: white;
  background: #185adb;
  cursor: pointer;
}

button:hover {
  background: #1245aa;
}

button:focus-visible {
  outline: 3px solid #172033;
  outline-offset: 4px;
}

.conteneur {
  max-width: 70rem;
  width: calc(100% - 2rem);
}

.bibliotheque {
  display: grid;
  gap: 1.5rem;
}

.sommaire ul {
  display: grid;
  gap: 0.5rem;
  padding: 0;
  margin: 0;
  list-style: none;
}

.sommaire button {
  width: 100%;
  text-align: left;
}

.sommaire button[aria-current="true"] {
  background: #183b56;
  box-shadow: inset 4px 0 0 #facc15;
}

#titre-chapitre {
  margin-top: 0;
}

#contenu-chapitre {
  overflow-wrap: anywhere;
}

@media (min-width: 48rem) {
  .bibliotheque {
    grid-template-columns: 16rem minmax(0, 1fr);
    align-items: start;
  }
}