Trouble with section/subchapters

[lukitoziomal]

Is there a way to add subchapters in section and they'll start after each other? If I do c1.content += c2.content it works, however I can't link c2 to TOC.
When I add c1 and c2 separately TOC works fine, but c2 starts in a new page instead after c1.
I've tried css page-break-before/after:avoid but that's seems not working.