Comment counter background color

Hello, can one change the background color of the comment counter somewhere in the backend or is it only with CSS? See the screenshot:https://www.dropbox.com/s/yvk54g72httxthx/Screenshot%20%282%29_LI.jpg?dl=0

Try this code:

/* Comments Bubble Color */
.td-module-comments a{
background-color:Red;
}
.td-module-comments a:after{
border-color: red transparent transparent transparent;
}