A confusion i have about HTML "classes" : <p>Hello and thanks in advance. In HTML I know that a "class" will not really have an effect unless it is related to something in CSS or JS. At the same time, I find some "classes" that do affect the structure of a documents even without an associated CSS, such as "class="col-md-12" for example. Can someone explain why some classes work independent of CSS? And how to know them.</p>
