Styles in report table

Question

So it doesn't appear that putting a style into the Report: Column: CSS Style does anything. It doesn't override an existing style. As such, how do I custom style a column in a report? I'd like to use the following style to create vertical "sections" in the report. I can't seem to find a way to use it from the styles, and I can't find anything in a reference for how to use it in an inline style.
td.l {border-left:1px solid black}

Answer 1

So it doesn't appear that putting a style into the Report: Column: CSS Style does anything. It doesn't override an existing style.No. That property causes the cell value to be generated inside a SPAN element, and the style is applied to this inline element rather than the entire table cell. This has been a problem since the dawn of time, as it's not what anyone actually wants it to do, and Oracle have thus far been immune to enhancement requests to produce the expected behaviour.
As such, how do I custom style a column in a report? I'd like to use the following style to create vertical "sections" in the report. I can't seem to find a way to use it from the styles, and I can't find anything in a reference for how to use it in an inline style.Vertical breaking of a table in this way is achieved using the COLGROUP/COL elements:
http://reference.sitepoint.com/html/colgroup
As this type of column grouping is going to be specific to a single report or family of reports it needs to be implemented in APEX using a custom named-column report template, where the COLGROUPs/COLs can be specified in the template Before Rows property.
http://download.oracle.com/docs/cd/E14373_01/appdev.32/e11838/themes.htm#BABFFGG
Adding suitable CLASS attributes to the COLGROUPs/COLs will enable styles to be applied as desired, such as thicker borders at COLGROUP boundaries (although support for this may not be forthcoming in some browsers: YMMV.)