Here’s my basic SVG:

<div style="padding:0px; width:500px; height:100px; background-color:#cdc8c8;">
  <svg width="100%" height="100%" viewBox="0 0 380 30" version="1.1" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" xml:space="preserve" xmlns:serif="http://www.serif.com/" style="fill-rule:evenodd;clip-rule:evenodd;stroke-linejoin:round;stroke-miterlimit:2;">
    <g transform="matrix(0.979791,0,0,1.03566,-56.9337,-435.053)">
      <rect x="58.108" y="420.073" width="387.838" height="28.967" style="fill:rgb(103,177,193);" />
    </g>
  </svg>
</div>

which renders as:

Now, if I wrote the same on an html page and I export the PDF with this code:

ConverterProperties converterProperties = new ConverterProperties();
converterProperties.SetBaseUri(AppDomain.CurrentDomain.BaseDirectory + "templates/report/");
using (var newFileStream = new FileStream(reportPathPDF, FileMode.Create))
{
    var pdfWriter = new PdfWriter(newFileStream);
    PdfDocument pdf = new PdfDocument(pdfWriter);
    pdf.SetDefaultPageSize(PageSize.A4);
    var document = HtmlConverter.ConvertToDocument(htmlContent, pdf, converterProperties);
    document.Close();
}

When I open the PDF, here’s the result:

Why this? Where am I wrong?