UI: Adjusted Import Modal Styles

[ellekasai]

I adjusted the styles of the import modal.

• Adjusted spacing
• Adjusted font sizes

Before	After

[Komediruzecki]

Maybe a note on the text above.

'Select how you want to import files ( 5Mb max per file )'

The parentheses never have inner spaces, only outer.
Unit and number are always separated by a space. If we want to be exact is 'Mb' megabyte or megabit, mebibyte or mebibit?

It would be nicer:

'Select how you want to import files (5 MB max per file)'
(assuming MB is megabyte in computer science = 1 MB = 1000000 B or 1 Mebibyte = 1024 * 1024 B)

Maybe this shouldn't be in this PR as a fix, but maybe another

[Rokt33r]

@Komediruzecki Thanks for the suggestion. I'll fix it by myself!