Open the Extensions sidebar panel in VS Code. View → Extensions
Search for Vivid Blue
Click Install
When prompted, select Electric Purple as the color theme
In case of not being prompted to select a Colour Theme upon installing, go to the menu bar and select: Code (File, on Windows) > Preferences > Color Theme > Vivid Blue. Alternatively, you can use the shortcut ⌘/Ctrl + K > ⌘/Ctrl + T and select Vivid Blue.