Yes Antd have predefined classes like bootstrap
If you want to center element use justify="center" It will work only on Row
but you can customize the antd element by using @emotion/styled package.
You need to inspect the button and get the button class from the element tab

Now you need to create a custom style for the button
Step 1: you need to import @emotion/styled
import Styled from "@emotion/styled";
Step 2 : Now Override the CSS of the Button
const CustomButton = Styled(Button)`
.ant-btn-primary{
background-color: #4BA461;
}
`
Step 3 Now use this CustomButton where you want like
<CustomButton>Register</CustomButton>
Installation Process
npm install --save @emotion/styled
or
yarn add @emotion/styled
You can learn more about emotion/styled from https://emotion.sh/docs/install