Hi, i've this page

How you can see, the light purple part begins togheter with the other colors squares...It seems that it's caused becaus i've setted the "settore" divs with float:left... Placing it on "settoreFoto" too, the problem solves, but i want to uderstand for what reason happen this.. It's haven't a logic sense

My goal is to place the purple part UNDER the three initial squares, with a 20px margin