remove line under widget title

oh just realized it didn’t work out as I tried to.
I totally removed this line, even when there is a title. Could you tell me what I should write in the CSS to display the line when title is used and remove it when the widget is used without title. It’s concerning the “section title line”.
thanks!

you’re sure?

In this website http://slowup.basel-dreiland.ch there is a line when using the title (check: http://slowup.basel-dreiland.ch/de/strecke/) and no line when without title (maskitto blog widget), check: http://slowup.basel-dreiland.ch/

For a former colleague created the page, I have no clue what he did…:-(

Hi there
it seems to work now- I did anything else than updating the theme.
Thanks for your help in all of my questions and sorry for being such a fool in website stuff 😉

Merry christmas!