Give the <strong> tag some CSS (the .content-body resets it)

Docker-DCO-1.1-Signed-off-by: SvenDowideit <SvenDowideit@home.org.au> (github: SvenDowideit)
Merge pull request #7789 from SvenDowideit/add-css-for-strong-tag

Give the <strong> tag some CSS (the .content-body resets it)