How do I change themes in IntelliJ Community Edition?
Choose Appearance & Behavior | Appearance in the Settings/Preferences dialog (Ctrl+Alt+S).
Get the UI theme right from the list of Themes available:
IntelliJ Light: This is a traditional light theme meant to handle IntelliJ-based IDEs
macOS Light or Windows 10 Light: This OS-specific light theme is available in the form of bundled plugin
Darcula: This is a default mode of dark theme
High contrast: This is a theme meant for users who face color vision deficiency
Preferences | Appearance & Behavior | Appearance Choose Sync with OS for letting IntelliJ IDEA identify the present system settings. You can also leverage the light theme or default dark as needed.