Flickity SVG icons doesn't show

Question

I copied the same code from the documentation but the svg arrows won't show.

<div class="gallery js-flickity" data-flickity-options='{ "wrapAround": true }'>
<div class="gallery-cell"></div>
<div class="gallery-cell"></div>
<div class="gallery-cell"></div>
<div class="gallery-cell"></div>
<div class="gallery-cell"></div>
</div>

I tried adding the path to the icon but it still doesn't show, and the css and js files are exactly like the documentation.