Keep together in pdf export

There is no real solution for this.

In theory it should work with "page-break-before", "page-break-after" and especially with "page-break-inside". For example, adding the following code to your PDF export stylesheet should prevent paragraphs from breaking.

p {
page-break-inside: avoid;
}

The problems is, it seems "page-break-inside" is not supported by the confluence CSS renderer. So all you can do, is try to find some solution with "page-break-after" or "page-break-before".