btn btn-primary btn-sm change style using css code example

Example 1: bootstrap default button

Primary
Secondary
Success
Danger
Warning
Info
Light
Dark
Link
Link
Button



Primary
Secondary
Success
Danger
Warning
Info
Light
Dark
Large button
Large button
Small button
Small button
Primary link
Link
Primary button
Button
Primary link
Link

  Single toggle


  
     Checked
  


  
     Active
  
  
     Radio
  
  
     Radio
  

Example 2: bootstrap Button tags

The .btn classes are designed to be used with the  element. 
However, you can also use these classes on  or  elements
(though some browsers may apply a slightly different rendering).

When using button classes on  elements that are used to trigger in-page 
functionality (like collapsing content), rather than linking to new pages or 
sections within the current page, these links should be given a role="button" 
to appropriately convey their purpose to assistive technologies such as screen 
readers.

Link
Button