Install the Stylus app for Google Chrome. It can be found here
chrome.google.com

First go to www.marapets.com

Click on the S up next in the top right



click add style for: this URL



in the code box type in A:visited {color: white ! important}

You don't have to use white, you can use whatever color you want. I prefer white myself is all.

At the bottom of the box make sure it says Applies to URLs starting with (that's a drop box) and in the box next to that www.marapets.com





DO NOT FORGET to clear your history every day so that the colors will reset to black and you will know who you haven't visited that day.