Adding your own classes and ids to elements is indispensable when writing CSS. You can also make use of Bootstrap's hundreds of utility classes which can make your life easier.
Bootstrap Studio offers a nice and easy way to add attributes to HTML elements. To do it, click the Attributes panel on the bottom of the HTML tab.
Note: You can add any CSS class that you wish, but some, like in the picture above, are locked. To change locked classes in Bootstrap Studio, you need to modify the component's settings in the Options panel.
To navigate the Attributes form use Tab, Shift+Tab and Enter. The attributes are applied automatically to the element, and full Undo/Redo history is retained.
Note: The 'on' event attributes are disabled for security reasons. You can attach event listeners by writing JS code with jQuery instead.