Customize Gyaanmitra
Themes
Color themes, file icon themes, and product icon themes. Switch each one on its own, or install more from Open VSX.
Color themes
Run Preferences: Color Theme from the Command Palette (Ctrl+K Ctrl+T) to preview installed color themes with the arrow keys. The whole window updates as you move through the list, so you can see a theme before you keep it.
Built-in themes
Several dark and light themes are included, including high-contrast ones. See Accessibility.
More on Open VSX
Search "theme" in the Extensions view. Most install and switch right away, with no reload.
File icon themes
A file icon theme is separate from your color theme. It sets the icons next to file and folder names in the Explorer and in editor tabs. Switch one with Preferences: File Icon Theme.
Product icon themes
The icons in the window itself (the Activity Bar, toolbar buttons, and the rest) are another choice. Set them with Preferences: Product Icon Theme. You can restyle those icons without changing file icons or colors.
Auto-switching with your OS
Set window.autoDetectColorScheme to true, and set both
workbench.preferredDarkColorTheme and workbench.preferredLightColorTheme.
Gyaanmitra will follow your operating system's light and dark mode, so you
do not switch by hand.
Writing your own theme
A color theme is a JSON file that maps workbench pieces and syntax tokens to colors. Start one with Developer: Generate Color Theme From Current Settings, edit the file, and package it as an extension. You can install it locally, or publish it to Open VSX for other people.