How to draw a custom underline

A custom underline can be drawn by using background: linear-gradient. The following is an example of a specific CSS description.

.marker_new{ 
 background: linear-gradient(transparent 70%, #ffdcb8 0%); 
 display: inline; 
 /*Adjust the padding below for a horizontal margin or shifting down*/ 
 padding: 0 2px 4px; 
}