An example of this theme.
I have always loved the base Vibrant Ink included with RStudio 1.2 but I thought it could use a bit of flair. This theme is also friendly with the line highlight option found under Tools > Global Options > Code > Display called Highlight selected line, which I find particularly helpful in a dark theme when debugging code.
Before you begin, create the following directory if it does not already exist: C:\ProgramData\RStudio
Make sure you're running RStudio 1.2 or later Run this:
rstudioapi::addTheme("https://raw.githubusercontent.com/jrausch12/morevibrantink/master/more_vibrant_ink.rstheme", TRUE, TRUE)
The above line will pull my theme down into your theme folder and override globally whatever theme you're currently using. Can be changed at any time by going to Tools > Global Options > Appearance
Do the following: Download the rstheme file to your local directory. Then, go to RStudio's ribbon and navigate to Tools > Global Options > > Appearance. From there, click on Add and navigate to the file you downloaded. Voila!