.companion-summary {
  background: var(--accent-soft);
  border: 0.08rem solid var(--line);
  border-radius: 0.55rem;
  margin: 1.2rem 0 2rem;
  padding: 1rem 1.2rem;
}

.companion-summary p:first-child {
  margin-top: 0;
}

.companion-summary p:last-child {
  margin-bottom: 0;
}

.companion-group {
  margin: 2.4rem 0;
}

.companion-route-list {
  display: grid;
  gap: 0.7rem;
  grid-template-columns: repeat(auto-fit, minmax(min(100%, 18rem), 1fr));
  list-style: none;
  padding: 0;
}

.companion-route-list a {
  background: var(--panel);
  border: 0.08rem solid var(--line);
  border-radius: 0.45rem;
  display: block;
  height: 100%;
  padding: 0.8rem 0.9rem;
  text-decoration: none;
}

.o001solution,
.o001readerwork,
.companion-environment {
  border: 0.08rem solid var(--line);
  border-radius: 0.55rem;
  margin: 2rem 0;
  overflow-wrap: anywhere;
  padding: 1rem 1.15rem;
}

.o001solution,
.o001readerwork {
  background: var(--panel);
}

.companion-environment {
  background: var(--paper);
  border-left: 0.28rem solid #6957a5;
}

.companion-environment.defn {
  border-left-color: #2878a9;
}

.companion-environment.exam,
.companion-environment.rem {
  border-left-color: #4d7c35;
}

.companion-environment.proof {
  border-left-color: var(--line);
  border-left-style: dotted;
}

.o001statement,
.o001result,
.o001sourcehint,
.o001answer,
.o001proof {
  background: var(--paper);
  border-left: 0.24rem solid var(--line);
  margin: 1.2rem 0;
  padding: 0.55rem 0.9rem 0.8rem 1rem;
}

.o001statement,
.o001result,
.o001sourcehint {
  border-left-color: #2878a9;
}

.o001answer,
.o001proof {
  border-left-color: #6957a5;
}

.component-heading,
.block-heading {
  color: #254d6d;
  line-height: 1.25;
}

.component-heading {
  margin: 0 0 0.55rem;
}

.block-heading {
  font-size: 1.05rem;
  margin: 0.2rem 0 0.55rem;
}

.component-meta {
  color: var(--muted);
  font-size: 0.9rem;
  margin: 0.35rem 0 0.8rem;
}

.provenance-details {
  border-bottom: 0.08rem solid var(--line);
  margin: 0.55rem 0 1rem;
  padding-bottom: 0.7rem;
}

.provenance-details code {
  overflow-wrap: anywhere;
}

.source-reader-link {
  font-weight: 700;
}

.text-diagram {
  background: var(--paper);
  border: 0.08rem solid var(--line);
  border-radius: 0.45rem;
  margin: 1rem auto;
  max-width: 34rem;
  padding: 0.8rem 1rem;
  text-align: center;
}

.text-diagram-visual {
  background: transparent;
  color: var(--ink);
  display: block;
  font-size: clamp(0.82rem, 2.4vw, 1rem);
  margin: 0 auto 0.7rem;
  overflow-x: auto;
  padding: 0;
  white-space: pre;
}

.text-diagram-caption {
  color: var(--muted);
  display: block;
  text-align: left;
}

.book-nav .nav-divider {
  border-top: 0.08rem solid var(--line);
  margin-top: 0.7rem;
  padding-top: 0.7rem;
}

@media (prefers-color-scheme: dark) {
  .companion-environment,
  .o001statement,
  .o001result,
  .o001sourcehint,
  .o001answer,
  .o001proof {
    background: #101820;
  }

  .text-diagram {
    background: #101820;
  }

  .component-heading,
  .block-heading {
    color: #b6e1ff;
  }
}

@media (max-width: 58rem) {
  .book-nav {
    max-height: 18rem;
    overflow-y: auto;
  }

  .book-nav__title {
    background: var(--panel);
    position: sticky;
    top: 0;
    z-index: 1;
  }
}

@media print {
  .provenance-details {
    break-inside: avoid;
  }

  .o001solution,
  .o001readerwork,
  .companion-environment {
    break-inside: avoid-page;
  }
}