<!DOCTYPE html>
<style>
path {
  vector-effect: non-scaling-stroke;
  stroke-width: 10px;
  stroke: green;
}
</style>
<svg>
  <path d="M20,10L20,10M220,110L220,110" stroke-linecap="round"/>
  <path d="M220,10L220,10M20,110L20,110" stroke-linecap="square"/>
</svg>