CSS selectors, target an empty span but not span that has an <a> tag or tags in it

I have these two markup up patterns:

<h3>
    <span>Title</span>
    <span></span>
</h3>

and

<h3>
    <span>Title</span>
    <span><a>link</a><a>link</a></span>
</h3>

I want to target the former but not the latter with CSS and use ::after to insert a visual flourish. I prefer not to use a class. I just can’t seem to get it!

h3>span+span:not(h3>span+span>a)::after {
    border: solid 1px transparent;
    content: '\2199';
    display: inline-block;
    color: gray;
}

>Solution :

Use :not(:has(*)) to select an empty element (more detail from my blog: https://css-tip.com/number-elements-has-selector/)

h3 span:last-child:not(:has(*))::after {
  border: solid 1px transparent;
  content: '\2199';
  display: inline-block;
  color: gray;
}

<h3>
  <span>Title</span>
  <span></span>
</h3>
and

<h3>
  <span>Title</span>
  <span><a>link</a><a>link</a></span>
</h3>