they are already distinguishable by color without any change. this is about comments although it marks only comments as new it hasn't seen before regardless if you read them or not.

This gave me the idea that I would like that standard everywhere. This convention is just so helpful. Maybe replacing with an outline on more heavily styled links, so as not to break layouts too much.

It is standard everywhere unless a site explicitly overrides it.

For example, do a Google search and click one of the links. Now do the same search again. The link you followed last time is now purple instead of blue. On Hacker News the links go a lighter grey.

Yes I know, but a lot of websites override it, I'd just like a unified style everywhere. To be honest I'd like consistent styling in a lot more places and I know of some add-ons that get pretty close but not quite.

Sorry, yeah, so you meant it'd be nice to have a feature/add-on that overrides the link colouring to be the same on every site. Absolutely. We had that once, in those distant days before CSS...

----

Edit:

This works on Firefox:

- Install Stylus[0].

- Click the toolbar icon and choose Manage.

- Click "Write new style"

- Enter and save this:

    a:link {
        color: #0000EE;
    }

    a:visited {
        color: #551A8B;
    }

[0] https://addons.mozilla.org/en-US/firefox/addon/styl-us/

----

Edit 2:

In Firefox WITHOUT installing any add-ons:

- Go to about:config

- Set toolkit.legacyUserProfileCustomizations.stylesheets to true

- Press Alt, click Help -> More Troubleshooting Information

- Next to "Profile Folder", click Open Folder

- Create a new folder there called "chrome"

- Make a file in that folder called userContent.css

- Enter the following CSS:

    a:link {
        color: #0000EE !important;
    }

    a:visited {
        color: #551A8B !important;
    }

- Restart Firefox

Turns out you can do what the top comment by chhickman is doing without any addon as well. Follow my steps above in "Edit 2", and add this to your CSS file:

    @-moz-document domain(news.ycombinator.com) {
      a:link {
        color: orange !important;
      }
      
      /* visited link */
      a:visited {
        color: green !important;
      }
    }

Per-domain custom CSS supported out of the box!

Is it not the standard everywhere? All my links, on every page, are lighter when visited. I suppose some sites might override this, but I've rarely seen it.