-- Standard button -->
                    <button type="button" class="btn btn-default">Default</button>
                    <!-- Provides extra visual weight and identifies the primary action in a set of buttons -->
                    <button type="button" class="btn btn-primary">Primary</button>
                    <!-- Indicates a successful or positive action -->
                    <button type="button" class="btn btn-success">Success</button>
                    <!-- Contextual button for informatio