Column Width & Margin Updates

Hello,

I am trying to decrease the margin between thirded columns, however, when I add the following quick CSS the margins between the columns do not seem to decrease. Perhaps I am editing the incorrect div tag?

div .av_one_third {
	
  margin-left: 0.6%;
  width: 32.93%;
}
div .av_two_third {
  margin-left: 0.6%;
  width: 66.46%;
}