message: remove redundant margin
  the original variables were overwritten in the only place of use (workflow scenario)
diff: .thread-header__label {
  color: var(--boxel-purple-400);
  font: 600 var(--boxel-font-xs);
  - margin-left: var(--boxel-sp);
  letter-spacing: var(--boxel-lsp-xl);
  text-transform: uppercase;
  }
  /* Not using variables for margin-top because it seems to make a significant difference to typography (@Aierie's judgement) */
  margin-top: 4px;
  margin-bottom: var(--boxel-sp-xxxs);
  - margin-left: var(--boxel-sp);
  font: 700 var(--boxel-font-lg);
  letter-spacing: var(--boxel-lsp-xs);
  }
  