Buttons

Button class= » » Description
btn Standard gray button with gradient
btn btn-primary Provides extra visual weight and identifies the primary action in a set of buttons
btn btn-info Used as an alternative to the default styles
btn btn-success Indicates a successful or positive action
btn btn-warning Indicates caution should be taken with this action
btn btn-danger Indicates a dangerous or potentially negative action
btn btn-inverse Alternate dark gray button, not tied to a semantic action or use

Link
<a class="btn" href="">Link</a>
<button class="btn" type="submit">Button</button>

More info about Buttons here