Should be easy, right? Just set the outer containing div\'s padding to zero, and set the two side-by-side divs inside the outer div to have margin:0 but that\'s having no effe
Like @Juan Lanus said in his answer, it is the whitespace causing your issue.
An additional solution is to set font-size: 0px on the containing div.
font-size: 0px
But you will need to then also set font-size: initial (or to a non-zero value) on the children div so you can still see your text.
font-size: initial