Style classes don't respect the implied hierarchy of the structure of the table to which they're applied.
In my particular case, the columns[n].style.classes styles override the columns[n].footer.style.classes styles. I don't think this should be the desired behavior.
The hierarchy implied in the table component styles is not preserved in the style.css document. Therefore, any conflicting styles applied to an element in the table will be resolved based on the order of definition of the style classes, completely ignoring the hierarchy in the Ignition Designer.
Because the class "table-header" is defined before "table-number", the styles in "table-header" get overridden by the styles in "table-number".
My suggestion is to revamp the way styles are applied to elements (like those of the table component) with cascading styles.