Your question is more CSS related than Outsystems.
1- you need to find out which part in the CSS makes the font-color of your link that color while hovering.
-> in chrome, right click your mouse and select Inspect. With the button i have circled you can go to select mode and click the part in your web that you need to find out.

2- when you have found out 1, you need to put in css with higher specificity for your problem. To find out how:
https://www.w3schools.com/css/css_specificity.asp
Its quote a lot to explain here on how to find this, if your CSS knowledge is next to none, but i hope this helps you a but.
Good luck!