How to create text with a background color instead of changing the foreground color in thunderbird

Thunderbird allows in the compose window to set the foreground color of
a text and the whole background, if composing an HTML e-mail.

So you can set only the foreground color of the text:

But this week, I got an e-mail viewed in thunderbird, where the background
color of a line was set and this was much more readable than the foreground setting the foreground color. The foreground color has to be some "dark"
color to get a readable text.

In Thunderbird it is not directly possibly, by selecting and changing the color, but the tool allows to insert directly HTML-code via the menu:


You have to select your text and open the menu-Item as described above:

Surround the text by

<span style="background-color:yellow"></span> 

After inserting and pressing "Insert", you get the text with a background color:

If the text continues, you can select the text and execute the menu
"Format-> Discontinue Text Styles"

and the next text comes with standard formating.