The container class has different maximum widths depending on the screen size: 540px for screens 576px and up, 720px for screens 769px and up, 960px for screens 992px and up, and 1210px for screens 1200px and up.

The row class uses flexbox for layout and has negative margins to offset the padding of the columns.

The col classes define the width of columns in a 12-column grid system, with different widths for different screen sizes (e.g., col-1 is 8.333333% width, col-2 is 16.666667% width, etc.).

The nav class is used for navigation elements and includes styles for nav-tabs and nav-pills, which have different visual styles for active and disabled states.

The navbar class is used for navigation bars and includes styles for alignment, padding, and brand elements.