Custom fonts not working in Generated PDF using WKHTMLTOPDF Library

I am using Laravel 5.1 SnappyPDF wrapper, which is using WKHTMLTOPDF library. I am trying to include some custom google fonts for my PDF file, but those fonts are not working in generated PDF file.

I tried, converting fonts into Base64 and also tried to include fonts by absolute URL and relative URL, also tried many answers available at stack overflow but none of them worked for me. How to fix this issue.

//Calling fonts
@font-face {
    font-family: Roboto Condensed;
    src: url("/fonts/RobotoCondensed-Regular/RobotoCondensed-Regular.ttf");
}
@font-face {
    font-family: 'Open Sans';src: url("/fonts/OpenSans/OpenSans-Regular.ttf");
}

@font-face {
    font-family: 'Open Sans Semi Bold Italic';
    src: url("/fonts/OpenSans/OpenSans-SemiboldItalic.ttf");
}

 //implenting fonts
.report-page2-col-wrapper .col-heading{
    font-family:"Open Sans Semi Bold Italic";
    font-size:12pt;
    line-height:17pt;
}

see difference in screen shots

1) This is web browser HTML version, looks find and fonts implementing properly

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2) This is Generated PDF version, fonts not applying properly

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via Chebli Mohamed