Посмотрите на preserveAspectRatio и убедитесь, что все элементы html, body и svg занимают 100% высоты области просмотра.
html {
height: 100%;
}
body {
margin: 0;
background: #4C0082;
height: 100%;
}
svg {
height: 100%;
width: 100%;
}
<svg preserveAspectRatio="xMidYMid meet" viewBox="0 0 960 560">
<linearGradient id="SVGID_1_" gradientUnits="userSpaceOnUse" x1="162.3691" y1="646.5293" x2="893.0117" y2="646.5293" gradientTransform="matrix(0.8443 -0.5359 0.5359 0.8443 -42.54 93.5288)"> <stop offset="0" style="stop-color:#4C0082"/> <stop offset="0.385" style="stop-color:#4C0382"/> <stop offset="0.6165" style="stop-color:#4D0B81"/> <stop offset="0.8074" style="stop-color:#4F1980"/> <stop offset="0.9753" style="stop-color:#522D7E"/> <stop offset="1" style="stop-color:#52317E"/> <stop offset="1" style="stop-color:#52317E"/></linearGradient><polyline fill="url(#SVGID_1_)" points="822.948,62.45 1303.946,548.438 674.11,919.56 259.071,124.032 "/><polyline fill="none" points="111.374,570.263 560.868,-4.484 -31.051,-20.646 -66.404,551.071 -30.041,569.253 111.374,570.263 -338.119,1145.007 "/><polyline fill="#11102F" points="1398,-193 696,-193 258.103,-46.896 763.579,458.579 1008.067,314.586 "/><polyline fill="#410069" points="1035.566,291.588 334.097,701.066 1301.061,943.584 1213.131,524.346 "/><linearGradient id="SVGID_2_" gradientUnits="userSpaceOnUse" x1="-247.6929" y1="273.7153" x2="482.9502" y2="273.7153" gradientTransform="matrix(0.8443 -0.5359 0.5359 0.8443 -42.54 93.5288)"> <stop offset="0" style="stop-color:#4C0082"/> <stop offset="0.385" style="stop-color:#4C0382"/> <stop offset="0.6165" style="stop-color:#4D0B81"/> <stop offset="0.8074" style="stop-color:#4F1980"/> <stop offset="0.9753" style="stop-color:#522D7E"/> <stop offset="1" style="stop-color:#52317E"/> <stop offset="1" style="stop-color:#52317E"/></linearGradient><polyline fill="url(#SVGID_2_)" points="276.948,-32.55 757.946,453.438 128.11,824.56 -286.929,29.032 "/>
</svg>