/* ナビゲーション */
.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  background: var(--color-white);
  border-bottom: 1px solid var(--color-border);
  z-index: 100;
  display: grid;
  justify-items: center;
}

.nav__list {
  display: flex;
  justify-content: center;
  align-items: center;
  flex-wrap: wrap;
  gap: 36px;
  padding: 16px 40px;
  /* scroll-target-groupプロパティを設定 */
  scroll-target-group: auto;
  width: 100%;
}

.nav__link {
  color: var(--color-text);
  text-decoration: none;
  padding: 4px 0;
  font-weight: bold;
  text-decoration: none;
  text-underline-offset: 4px;
  transition:
    color 0.3s,
    text-decoration 0.3s;

  /* スクロール通過ずみ */
  &:target-before {
    color: var(--color-text-muted);
  }

  /* 現在表示中 */
  &:target-current {
    color: var(--color-primary);
    text-decoration: underline;
  }

  /* スクロール未到達 */
  &:target-after {
    color: var(--color-secondary);
  }
}

.main {
  max-width: 640px;
  padding: 120px 40px;
  display: grid;
}

.chapter {
  padding: 120px 0;
}

.chapter__title {
  font-size: 28px;
  margin-bottom: 36px;
  color: var(--color-primary);
}

.chapter__content {
  display: grid;
  gap: 16px;
}