The !important in bootstrap.css are added by Bootstrap itself. Give your CSS more weight then add !important and you'll override it. Example as follows.
Bootstrap:
Code:
.cb_template .text-primary {
color: blue !important;
}
Custom CSS
Code:
.cb_template .myclass .text-primary {
color: red !important;
}
CB provides a built in means of overriding CSS that takes care of load order for you so you don't even need to do the above. See the below on how to add CSS overrides to CB.
www.joomlapolis.com/blog/kyle/18711-template-css-overrides-made-easy
This would allow the below to work fine due to load order giving more weight to override styles.
Code:
.cb_template .text-primary {
color: red !important;
}