CODE EXAMPLE FOR CSS

set border color of svg

<svg class="highlight" width="86" height="68" viewBox="0 0 85.7 68.5">
  <polygon points="11 60.7 74.7 60.7 42.8 4.4 " />
</svg>

.highlight {
  fill: none;
  stroke-width: 3;
  stroke: #491EC4;
}