This is a companion discussion topic for the original entry at https://www.rstudio.com/blog/rstudio-ide-custom-theme-support
We’re excited to announce that RStudio v1.2 has added support for custom editor themes. Custom editor themes will allow you to adjust the background color of the editor and syntax highlighting of code in RStudio to better suit your own personal style.
New editor themes can be added to RStudio by importing a tmTheme or sharing an existing rstheme file. The tmTheme file format was first introduced for the TextMate editor, and has since become a standard theme format.