JSFiddle - React, Tailwind, and code Playground

by Mert Ener

HTML

<svg>
  <filter id="inset-shadow">
    <feComponentTransfer in=SourceAlpha>
      <feFuncA type="table" tableValues="1 0" />
    </feComponentTransfer>
    <feGaussianBlur stdDeviation="3" />
    <feOffset dy="-5" result="offsetblur" />
    <feComposite in2="offsetblur" operator="in" />
    <feComposite in2="SourceAlpha" operator="in" />
    <feMerge>
      <feMergeNode in="SourceGraphic" />
      <feMergeNode />
    </feMerge>
  </filter>
  <polygon points="0,0 100,100 200,0" style="fill:red" filter="url(#inset-shadow)" />
</svg>