.sd-tab-set.tabs-vertical {
  display: grid;
  /* The pane's track is floored at zero: a bare `1fr` means `minmax(auto, 1fr)`,
   * whose floor grows to the widest line the pane cannot break, like a long URL
   * in a code block, and pushes the pane under the sidebar. */
  grid-template-columns: minmax(7rem, max-content) minmax(0, 1fr);
  align-items: start;
}

/* No column gap: the marker of the active label then sits on the rule of the
 * pane, the way horizontal tabs merge an underline into an overline. */
.sd-tab-set.tabs-vertical > label {
  grid-column: 1;
  text-align: left;
  padding-right: 1rem;
  border-bottom: none;
  border-right: 0.125rem solid transparent;
}
.sd-tab-set.tabs-vertical > input:checked + label {
  border-right-color: var(--sd-color-tabs-underline-active);
}
.sd-tab-set.tabs-vertical > .sd-tab-content {
  grid-column: 2;
  /* Span every row, or the height of the pane inflates the first row and
   * pushes the labels down the rail. `1 / -1` counts from the last explicit
   * row, and the grid declares none, so the span overshoots any tab count. */
  grid-row: 1 / span 99;
  align-self: stretch;
  padding: 0 0 0 1.5rem;
  /* sphinx-design rules a pane with two shadows, one above and one below. A
   * single hairline down the left edge replaces them. */
  box-shadow: -0.0625rem 0 var(--sd-color-tabs-overline);
}

/* Too narrow for two columns: restate the values of sphinx-design, since a
 * shorthand cannot fall back to the value of another stylesheet. */
@media (max-width: 50em) {
  .sd-tab-set.tabs-vertical {
    display: flex;
    flex-wrap: wrap;
  }
  .sd-tab-set.tabs-vertical > label {
    padding: 1em 1.25em 0.5em;
    border-right: none;
    border-bottom: 0.125rem solid transparent;
  }
  .sd-tab-set.tabs-vertical > input:checked + label {
    border-bottom-color: var(--sd-color-tabs-underline-active);
  }
  .sd-tab-set.tabs-vertical > .sd-tab-content {
    align-self: auto;
    padding: 0.75rem 0;
    box-shadow:
      0 -0.0625rem var(--sd-color-tabs-overline),
      0 0.0625rem var(--sd-color-tabs-underline);
  }
}