I browsed into the MDN CSS documentation but I don't see any Combinators that can select the element I want to style.

```css
/* second-span red when first-span is present */
[first-span] ~ [second-span] {
  color: red;
}

/* first-span blue ONLY when second-span is present */
/* HOW TO ? */
[first-span] /* combinator doesn't exist */ {
  color: blue;
}
```

```html
<p>
  <span first-span="">I am #1</span><br>
  <span second-span="">I am #2</span>
</p>

<p>
  <span first-span="">I am #1</span>
  <!-- no second span -->
</p>

<p>
  <span second-span="">I am #2</span>
</p>
```

I try to apply a style to an element ONLY if another specified sibling is found among below siblings.

In the snippet, the first CSS statement is used to style an element if the left hand in the selection expression is found among above siblings. But it seems like there is not combinator to have the opposite effect.

How can I do that ?