Sirius UI is developed with Styled System. Styled System is a collection of utility functions that add style props to your React components and allows you to control styles based on a global theme object with typographic scales, colors, and layout properties.
You can visit reference table for full list of features that you can use with styled-system. Also, properties you can use for individual components are documented in their respective documentation pages. But generally, you can apply spacing styles to almost all of the components.