Turn all links "MidnightBlue":
% https://tex.stackexchange.com/questions/100905/best-practice-for-hyperref-link-colours
\usepackage[dvipsnames]{xcolor}
\newcommand\myshade{85}
\hypersetup{
colorlinks = true,
allcolors = MidnightBlue!\myshade!black,
}
Or if you want different colors for different links:
\newcommand\myshade{85}
\colorlet{mylinkcolor}{violet}
\colorlet{mycitecolor}{YellowOrange}
\colorlet{myurlcolor}{Aquamarine}
\hypersetup{
linkcolor = mylinkcolor!\myshade!black,
citecolor = mycitecolor!\myshade!black,
urlcolor = myurlcolor!\myshade!black,
colorlinks = true,
}