Safari changes the color of sites you have visited, but it is a rather subtle change from a dull dark blue to a dull purplish blue. My old eyes have trouble with that, and of course my old brain can barely keep up with where I am, much less where I’ve been. The solution is to highlight visited sites in a much more distinctive color. Unfortunately there isn’t a simple preference for this, but it can be done pretty easily with what’s known as a Style Sheet or .css file. Here is how to do it.

Create the Style Sheet: 

Select and Copy the following two lines of text.

a:visited

{color: #7FFF00 !important;}

Open a new TextEdit document and Paste the above text into it. The color #7FFF00 is chartreuse. You can replace it with the hex code for the color of your choice. Here is a handy color list. http://www.w3schools.com/colors/colors_names.asp  Just replace the 6 characters after the # sign with the 6 characters of your chosen color. Note that the 0 is the numeral zero, not the letter O.

Now go to Format in the top menu and click on Make Plain Text. Next go to File/Save As and save it to a convenient location (Documents, for instance). Be sure to save it with the css extension.

Link the Style Sheet to Safari:

Open Safari and go to Safari/Preferences/Advanced. Click on the style Sheet menu and choose Other. Navigate to your saved style sheet and select it. You may have to quit and restart Safari for the change to take effect.