1、下載主題包:
https://blog.jetbrains.com/idea/2019/03/brighten-up-your-day-add-color-to-intellij-idea/
2、啟動intelliJidea2019.1打開setting:

3、選擇plugins:

4、選擇install plugin from disk:

5、選擇你所下載的主題包jar:

6、重啟IntelliJIdea2019.1,然后進入setting中設(shè)置主題:

完成。
參考文檔:
http://www.jetbrains.org/intellij/sdk/docs/reference_guide/ui_themes/themes_customize.html
2019.1主題插件官方下載地址: