Full textblock background color – how to change

How would I change the background color of a single text-block so the whole text-box is included? I can’t get it to work.
My humble endevour with a class-tag didn’t work:

.blueback { background-color: #412F83; padding: 10px; height: 100%; }

Also i didn’t succeed with a div container:

#blueback {
    background-color: #412F83;
}

This is just covering only the text at the text-box. I need a full background including all elements within the text-box/text-block…
Please do you have any ideas…? Thanks!!

• This topic was modified 7 years, 9 months ago by beenee.