Hi,
I’m not sure I understand what you mean.
To clarify: Did you mean, you want the blue button block to have different styles on desktop, tablet and mobile?
If so, you do that by editing the page. The button is added as a content using GenerateBlocks on Gutenberg editor.
Luckily, GenerateBlocks has responsive settings for different viewports.
On Gutenberg, you can switch between viewport previews and GenerateBlocks viewport settings to edit the blocks as shown here: https://share.getcloudapp.com/P8uyNXjw
As for things that are not in the UI like color change on different viewports, you’ll have to use custom CSS codes with @media queries.