Because all ComboStrap UI component are implemented as super set HTML element, you can apply the class attributes.
The class attribute is used intensively by Bootstrap to apply the Bootstrap Layout Utilities.
ComboStrap already implements most of these utilities through the standard attributes but in the case that you need something really advanced, you can always take control over and apply them.
Example:
Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat.
<note class="invisible" >
A note that is no more visible
</note>
Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.
Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat.
A note that is no more visible
Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.
To be able to style as you wish, Combostrap adds a generated class for each element of a component.
More ? See component stylesheet in theming