.btn-outline-* ones to remove all background images and colors on any button..btn-outline-* ones to remove all background images and colors on any button..btn classes are designed to be used with the <button> element. However, you can also use these classes on <a> or <input> elements (though some browsers may apply a slightly different rendering)..btn-lg or .btn-sm for additional sizes..btn-lg or .btn-sm for additional sizes.<button>s as they use a pseudo-class. However, you can still force the same active appearance with .active (and include the aria-pressed="true" attribute) should you need to replicate the state programmatically.disabled boolean attribute to any <button> element.data-toggle="button" to toggle a button’s active state. If you’re pre-toggling a button, you must manually add the .active class and aria-pressed="true" to the <button>..button styles can be applied to other elements, such as <label>s, to provide checkbox or radio style button toggling. Add data-toggle="buttons" to a .btn-group containing those modified buttons to enable their toggling behavior via JavaScript and add .btn-group-toggle to style the <input>s within your buttons. Note that you can create single input-powered buttons or groups of them..button styles can be applied to other elements, such as <label>s, to provide checkbox or radio style button toggling. Add data-toggle="buttons" to a .btn-group containing those modified buttons to enable their toggling behavior via JavaScript and add .btn-group-toggle to style the <input>s within your buttons. Note that you can create single input-powered buttons or groups of them.