my hyperlinks have a mind of their own!

When ever I add a link, it seems to go whatever colour it wants, usually either blue or purple or red, (as if it is a link that has been selected on a webpage) How can i make them all the same colour when added?

this is the main page of conflict:

https://steel-city.co.uk/blog/index.php/promotional-products-from-oversees/

Cheers