If you want to enhance the appearance of your SVG, try using inline SVG code instead of setting it as a background. By doing this, you can easily manipulate the fill or stroke of the SVG using a CSS class.
<div class="submit-btn">
<svg class="svg-outline" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" version="1.1" id="Capa_1" x="0px" y="0px" viewBox="0 0 485.411 485.411" style="enable-background:new 0 0 485.411 485.411;" xml:space="preserve">
<g>
<path d="M0,81.824v321.763h485.411V81.824H0z M242.708,280.526L43.612,105.691h398.187L242.708,280.526z M163.397,242.649L23.867,365.178V120.119L163.397,242.649z M181.482,258.533l61.22,53.762l61.22-53.762L441.924,379.72H43.487 L181.482,258.533z M322.008,242.655l139.535-122.536v245.059L322.008,242.655z" />
</g>
</svg>
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</div>
<style>
.submit-btn {
display: inline-flex;
justify-content: center;
align-items: center;
flex-shrink: 0;
font-size: 1.25em;
color: #fff;
background: #17a2b8;
transition: 250ms ease;
border: 1px solid #fff;
border-radius: 3px;
padding: 5px 15px;
}
.svg-outline {
stroke: orange;
fill: #fff;
height: 45px;
width: auto;
transition: fill 250ms ease;
margin-right: 5px;
}
.submit-btn:hover {
background: #fff;
color: #17a2b8;
border: 1px solid #17a2b8;
}
.submit-btn:hover .svg-outline {
fill: #17a2b8;
}
</style>