Fix normal, hover and pressed states for links on new-tab/home page
As per the normal Fx convention, links should be:
- normal by default
- underlined + one shade lighter (
#FFD567
or proton yellow-30) on hover - normal + another shade lighter (
#FFEA80
or proton yellow-20) when pressed
(typically light theme goes darker on hover/pressed, but the foreground content is light on dark here)