am be1c90f5: am 4678625e: am 0707f784: am bf9d72ff: am 07816041: set fixed height for header div to ensure the next/prev links in the training bar are always aligned with TOC

* commit 'be1c90f569a3473412344dcc6cfd257398fcbdb5':
  set fixed height for header div to ensure the next/prev links in the training bar are always aligned with TOC