Adicionar filtros css

Caros, boa tarde.

Peguei esse código em css na internet e preciso alterar para webkit-filter, mas não consigo.
Alguém pode me ajudar, por favor?

.filter-gradient.gray:after{
/ IE9 SVG, needs conditional override of 'filter' to 'none' /
background: url(data:image/svg+xml;base64,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);
background: -moz-linear-gradient(top, rgba(35,37,38,1) 0%, rgba(65,67,69,0.87) 100%); / FF3.6+ /
background: -webkit-gradient(linear, left top, left bottom, color-stop(0%,rgba(35,37,38,1)), color-stop(100%,rgba(65,67,69,0.87))); / Chrome,Safari4+ /
background: -webkit-linear-gradient(top, rgba(35,37,38,1) 0%,rgba(65,67,69,0.87) 100%); / Chrome10+,Safari5.1+ /
background: -o-linear-gradient(top, rgba(35,37,38,1) 0%,rgba(65,67,69,0.87) 100%); / Opera 11.10+ /
background: -ms-linear-gradient(top, rgba(35,37,38,1) 0%,rgba(65,67,69,0.87) 100%); / IE10+ /
background: linear-gradient(to bottom, rgba(35,37,38,1) 0%,rgba(65,67,69,0.87) 100%); / W3C /
filter: progid:DXImageTransform.Microsoft.gradient( startColorstr='#232526', endColorstr='#de414345',GradientType=0 ); / IE6-8 /

}
Alterei para

.filter-gradient.orange:after{

-webkit-filter: hue-rotate(50deg);

}

Mas não funcionou minha alteração.

Obrigado pessoal

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