Stirling-PDF/stirling-pdf/build/resources/main/static/css/split-pdf-by-sections.css

.pdf-visual-aid {
  width: 150px; /* Adjust as needed */
  height: 200px; /* Adjust as needed */
  border: 1px solid black; /* Represents the PDF page */
  position: relative;
}
.line {
  position: absolute;
  background-color: red; /* Line color */
}