how to add customized color in boostrap as background code example

Example 1: bootstrap color variants

/* colors in bootstrap */
color : #007bff; /* primary */
color : #6c757d; /* secondary */
color : #28a745; /* success */
color : #ffc107; /* warning */
color : #dc3545; /* danger */
color : #17a2b8; /* info */
color : #f8f9fa; /* light */
color : #343a40; /* dark */

Example 2: change bootstrap background color

<style type="text/css">
   body { background: navy !important; } /* Adding !important forces the browser to overwrite the default style applied by Bootstrap */
</style>