DomException: Style declaration ending bracket missing when trying to render svg

[AesElh]

when attempting to render an svg file i'm getting

This exception was originally thrown at this call stack:
    SharpVectors.Dom.Css.CssStyleDeclaration.ParseString(string)
    SharpVectors.Dom.Css.CssStyleRule.Parse(ref string, object, bool, System.Collections.Generic.IList<string>, SharpVectors.Dom.Css.CssStyleSheetType)
    SharpVectors.Dom.Css.CssRuleList.Parse(ref string, object, bool, System.Collections.Generic.IList<string>, SharpVectors.Dom.Css.CssStyleSheetType)
    SharpVectors.Dom.Css.CssRuleList.CssRuleList(ref string, object, System.Collections.Generic.IList<string>, bool, SharpVectors.Dom.Css.CssStyleSheetType)
    SharpVectors.Dom.Css.CssStyleSheet.CssRules.get()
    SharpVectors.Dom.Svg.SvgDocument.GetFontUrl(SharpVectors.Dom.Css.CssStyleSheet, System.Collections.Generic.IList<System.Tuple<string, SharpVectors.Dom.Svg.SvgFontFaceElement>>, System.Collections.Generic.IDictionary<string, string>)
    SharpVectors.Dom.Svg.SvgDocument.GetFontUrls()
    SharpVectors.Dom.Svg.SvgDocument.OnLoaded()
    SharpVectors.Dom.Css.CssXmlDocument.Load(System.Xml.XmlReader)
    SharpVectors.Dom.Svg.SvgDocument.Load(string)

this is just a sample app with xaml of:

<UserControl x:Class="WindowsFormsApp2WebP.UserControl1"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
             xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
             xmlns:local="clr-namespace:WindowsFormsApp2WebP"
                xmlns:svgc="http://sharpvectors.codeplex.com/svgc/"
             mc:Ignorable="d" 
             d:DesignHeight="450" d:DesignWidth="800">
    <Grid>
        <svgc:SvgViewbox x:Name="MySvgViewbox" Source="background.svg"/>
    </Grid>
</UserControl>
i had to redact the original svg as it was proprietary , but the same error will show up on the original svg as well, because it's css related