When you need to override ant design(ui framework) theme, you need some step which described below.
If you imported the ant’s css file in elsewhere remove it
1- Install Dependencies
2- Edit Start and Build Commands in Packages.json
3- Place The Config Files Under the Project Root Folder
.babelrc file will be places under root folder
config-overrides.js files will be placed under the root folder
If you completed all steps you will see theme primary color changes.