.defs-header {
  display: flex;
  align-items: center;
  gap: 0.45rem;
  cursor: pointer;
  padding: 0.6rem 0;
  font-family: var(--sans);
  font-size: 0.8rem;
  letter-spacing: 0.07em;
  text-transform: uppercase;
  opacity: 0.5;
  user-select: none;
  border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
  margin: 0.75rem 0 0.75rem;
  transition: opacity 0.15s;
}
.defs-header:hover { opacity: 0.9; }
.defs-header .toc-chevron { transition: transform 0.2s; display: inline-block; }
.defs-header[aria-expanded="true"] .toc-chevron { transform: rotate(180deg); }
.tldr-coda {
  position: relative;
  margin-top: 1.5rem;
  padding-top: 2.5rem;
  text-align: center;
  font-family: var(--sans);
}
.tldr-coda::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 1px;
  background: linear-gradient(to right, transparent, var(--border), transparent);
}