Add Two Section ID

What is the reason for an ID ?
An ID should be unique – to have another section with same ID is wrong!
Or in other words – what is the superlative of unique ?
If your “first ID” is unique every added construction should be too !

https://www.w3schools.com/tags/att_global_id.asp

Definition and Usage
The id attribute specifies a unique id for an HTML element (the value must be unique within the HTML document).
The id attribute is most used to point to a style in a style sheet, and by JavaScript (via the HTML DOM) to manipulate the element with the specific id.

classes you are able to combine an this makes sense.
on that enfold field to insert the combined classes only seperated by a space
so if you have this for a div in your input filed abc def
the output will be div.abc.def
and you than can select each class seperatly

.abc { … }
.def { … }