Remove sidebar separator and reduce widgets margin

Customization
#1

Hello.
I am trying to remove the grey lines between sidebar widgets and then reduce the margin between the widgets. I already tried: to remove the separator which didn’t work.

.sidebar.sidebar-left{
  border:none;
}
.widget{
  border:none;
}

I did manage to reduce the margin-top between widgets like this: ( this reduced the margin-top which is probably because my language settings are hebrew ).

.widget {
	margin-bottom: -50px
}

all other things with margin and padding didn’t help.
Thank you in advance.