Logo in Rmarkdown HTML won't display when using CSS

[tanga94]

I am using the windmill template in the pagedreport package to create a report in Rmarkdown HTML. Instead of the default option of printing the title in the top left corner, I would like to insert a logo instead. I have tweaked the CSS code in the package to do this, however the image isn't displaying when I knit the report. Any suggestions on how I can fix this?

@page {

  @top-left {
    background-image: url(https://www.bon.com.na/CMSTemplates/Bon/Images/newlogo.png);
    background-repeat: no-repeat;
    background-size: 2cm;
    border-bottom: 5px solid var(--main-color);
    margin-bottom: 0.7cm;
  }
}