Use the whole class class, like you would do in your css stylesheet.
Specify the amount of widgets you want to use, or you want to use in a row.
Specify the margin the blocks should have.
To use this code, copy all of the code, open up the style.css file inside your theme and paste it in the file.
NB: I take no responsibility for this going wrong! Please make sure you have some idea of what you are doing and keep backups of your website!
JavaScript by djave