Formatting weasyprint footnotes to be smaller

I cannot get Weasyprint to output the reference number of a footnote to be smaller. It all comes out as the same size as the encompassing text.

[![enter image description here][1]][1]

CSS

@page {
    size: A4;

    @top-right {
        font-family: 'barlowlight';
        font-size: 0.75rem;
        content: "Report ID: dQ7g050OTY";
    }

    @bottom-right {
        font-family: 'barlowlight';
        font-size: 0.75rem;
        content: "Page " counter(page) " of " counter(pages);
    }

    @bottom-left {
        font-family: 'barlowlight';
        font-size: 0.75rem;
        content: "\00A9  Natural Capital Research 2022"
    }

    @footnote {
        font-size: 4px;
    } 

    border-bottom: #bada55 1px solid;
}
span.footnote { 
    float: footnote;
    font-size: 0.8rem;
   
  }

HTML

<section>
<p>To target ... <span class='footnote'>Footnote test</span></p>

Weasyprint is latest (56.1) [1]: https://i.stack.imgur.com/LVzLR.png