Creating SVG-Gradients
To use gradients in SVG, we first have to defines them in the <defs>
section inside the SVG.
<svg width="200" height="200" viewPort="0 0 200 200">
<defs>
<linearGradient id="gradient" x1="0" x2="0" y1="0" y2="1">
<stop offset="0%" stop-color="pink" stop-opacity="0" />
<stop offset="100%" stop-color="pink" />
</linearGradient>
</defs>
...
</svg>
After it is defined it can be used as follows
<rect x="0" y="0" width="200" height="200" fill="url(#gradient)" />
Code
<svg width="200" height="200" viewPort="0 0 200 200">
<defs>
<linearGradient id="gradient" x1="0" x2="0" y1="0" y2="1">
<stop offset="0%" stop-color="pink" stop-opacity="0" />
<stop offset="100%" stop-color="pink" />
</linearGradient>
</defs>
<rect x="0" y="0" width="200" height="200" fill="url(#gradient)" />
</svg>