public-web/layouts/partials/styles.html

<style>
  @font-face {
    font-family: "Spline Sans";
    src: url({{ "fonts/SplineSans-Regular.woff2" | relURL }}) format('woff');
    font-weight: 400;
    font-display: swap;
  }

  @font-face {
    font-family: "Spline Sans";
    src: url({{ "fonts/SplineSans-Medium.woff2" | relURL }}) format('woff');
    font-weight: 500;
    font-display: swap;
  }

  @font-face {
    font-family: "Spline Sans";
    src: url({{ "fonts/SplineSans-Bold.woff2" | relURL }}) format('woff');
    font-weight: 700;
    font-display: swap;
  }
</style>

{{ $style := resources.Get "style.css" }}
<link rel="stylesheet" href="{{ $style.Permalink }}" />