border-vertically.css

border-left: thick solid #ff0000;

.your-item {
  position: relative;
}

.your-item:after {
  content: '';
  height: 100%; //You can change this if you want smaller/bigger borders
  width: 1px;
  
  position: absolute;
  right: 0;
  top: 0; // If you want to set a smaller height and center it, change this value
  
  background-color: #000000; // The color of your border
}