Modul User 5-8 Suffix Background

Hey,
tried to change my backgroundcolour in a specific modul.
First I added in Modul the suffix to "_mwes"
Then I added in Template_css.css this code:

div.moduletable_mwes {
font-size:18px;
padding:50;
background:#81BEF7;
}

But in frontend now there is a ribbon showing that I don´t want to be shown.

How can I specify this special Modul User 5-8 with a certain bgcolour.
By the way, the colour should be the whole Module without a white border.

Hope You understood my problem/question and can help me.
Thanks so muc
Bye Klaus

If you use "_mwes" then you must also match original module class which is not always .moduletable.

" mwes" is better (first char is blank) becuse then you can use :

.mwes{
....
}

not worrying about module original class name