Simply download a CSS file and replace the one in Bootstrap. No messing around with hex values.
Bootstrap themes are licensed under Apache 2.0 and maintained by the community on GitHub.
Swatches are built for and tested with the latest version of Bootstrap. Older versions are also available for download.
Changes are contained in just two LESS files, enabling modification and ensuring forward compatibility.
An API is available for integrating with your platform. In use by WPBS, FusionLeaf, BootSnap, and others.
Check out my personal faves from the paid templates at WrapBootstrap.
Learn to code your own themes with these books from Amazon.