As far as I can see, a span defined is only addressable within the same (text)block. Is there any way to make that available on a global level?
The only trick half-way I currently see, is:
define a global class a relative style reflecting the modifications one is intending with a span. As relative style rule refer (descending) to new class name, which one has to use as the span name when marking respective parts of text. The global class (above) could be added at the top div per page
Above solution seems to work globally out of the box, just add the unique span to each part of text at any block at any page