<body>
<div class="window bg"></div>
</body>
.bg {
background: url(../../assets/images/fons/bg.svg) no-repeat center center ;
-webkit-background-size: cover;
-moz-background-size: cover;
-o-background-size: cover;
background-size: cover;
}
.window {
position: relative;
width: 95%;
min-height: 98vh;
margin-left: auto;
margin-right: auto;
margin-top: 1vh;
border-radius: 5px;
box-shadow: 0px 0px 10px 0px #000000;
min-width: 1200px;
}
<?xml version="1.0" encoding="utf-8"?>
<!-- Generator: Adobe Illustrator 22.1.0, SVG Export Plug-In . SVG Version: 6.00 Build 0) -->
<svg version="1.1" id="Слой_1" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" x="0px" y="0px"
viewBox="0 0 750.3 450" style="enable-background:new 0 0 750.3 450;" xml:space="preserve">
<style type="text/css">
.st0{fill:url(#SVGID_1_);}
</style>
<g id="bg">
<g>
<g>
<radialGradient id="SVGID_1_" cx="177.9216" cy="209.9861" r="519.3318" gradientTransform="matrix(1.2506 0 0 -1 -71.7218 452)" gradientUnits="userSpaceOnUse">
<stop offset="1.075270e-02" style="stop-color:#2C35A2"/>
<stop offset="0.1635" style="stop-color:#252C88"/>
<stop offset="0.3975" style="stop-color:#1B2167"/>
<stop offset="0.621" style="stop-color:#15194F"/>
<stop offset="0.8273" style="stop-color:#101540"/>
<stop offset="1" style="stop-color:#0F133B"/>
</radialGradient>
<rect y="0.3" class="st0" width="750.3" height="450"/>
</g>
</g>
</g>
</svg>
width="750.3" height="450" preserveAspectRatio="none slice"
width="750.3" height="450" preserveAspectRatio="none slice"
<?xml version="1.0" encoding="utf-8"?>
<!-- Generator: Adobe Illustrator 22.1.0, SVG Export Plug-In . SVG Version: 6.00 Build 0) -->
<svg version="1.1" id="Слой_1" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" x="0px" y="0px"
viewBox="0 0 750.3 450" style="enable-background:new 0 0 750.3 450;" xml:space="preserve" width="750.3" height="450" preserveAspectRatio="none slice">
<style type="text/css">
.st0{fill:url(#SVGID_1_);}
</style>
<g id="bg">
<g>
<g>
<radialGradient id="SVGID_1_" cx="177.9216" cy="209.9861" r="519.3318" gradientTransform="matrix(1.2506 0 0 -1 -71.7218 452)" gradientUnits="userSpaceOnUse">
<stop offset="1.075270e-02" style="stop-color:#2C35A2"/>
<stop offset="0.1635" style="stop-color:#252C88"/>
<stop offset="0.3975" style="stop-color:#1B2167"/>
<stop offset="0.621" style="stop-color:#15194F"/>
<stop offset="0.8273" style="stop-color:#101540"/>
<stop offset="1" style="stop-color:#0F133B"/>
</radialGradient>
<rect y="0.3" class="st0" width="750.3" height="450"/>
</g>
</g>
</g>
</svg>