.stack {
  display: flex;
  flex-direction: column;
  flex-grow: 1;
  justify-content: flex-start;
}

.stack > * {
  margin-block: 0;
}

.stack > * + * {
  margin-block-start: var(--stack-margin);
}

.stack-s > * + * {
  margin-block-start: var(--space-xs-s);
}

.stack-xs > * + * {
  margin-block-start: var(--space-3xs-2xs);
}

.stack-0 > * + * {
  margin-block-start: 0;
}

.stack:only-child {
  /* ↓ `height` in horizontal-tb writing mode */
  block-size: 100%;
}