The Sass compiling process makes it possible to import and combine multiple files into a single, unified CSS file. We can specify the order of import, and organize the resulting style sheet precisely as needed for our desired cascade.

Thus, Bootstrap's import file, bootstrap.scss, begins with imports for essential variables and mixins. Then, it imports a Sass version of normalize.css (in place of a CSS reset), followed by basic styles for print media. Then, it moves to core styles, including the new reboot module (_reboot.scss), typographic fundamentals (_type.scss), and more specific details. Thus, the first several lines of the current bootstrap.scss file are given as follows:

// Core variables and mixins 
@import "variables"; 
@import "mixins"; 
 
// Reset and dependencies 
@import "normalize"; 
@import "print"; 

The resulting CSS file will be a single, unified whole, with styles cascading down from the general to the specific, from components...