message: feat(hr): add default rule styles
diff: @@ -126,6 +126,13 @@ blockquote code {
  font-weight: 500;
  }
  +hr {
  + border-color: var(--line-rule-color);
  + border-style: solid;
  + border-width: 1px 0 0 0;
  + margin: 1rem 0;
  +}
  +
  code {
  background-color: var(--code-background-color);
  border-radius: 4px;
  