Option: Using :focus pseudo-class

Your CSS already defines styles for the .btn-primary:focus state. You can add the outline: none; property to remove the default browser outline:

.btn-primary:focus {
  outline: none !important;  
  box-shadow: none !important;
  background-color: #b80c09;
}

Also check the cache in the browser, is there any conflicting styles in Bootstrap that is why I put !important to override.

The :focus pseudo-class applies styles when an element receives focus and the outline property controls the outline around an element when focused.