The reason this is happening is because the div
elements are being floated. When you lower the screen size, the block is becoming longer (taller) and the float is breaking. You can clear every other line by adding this snippet:
.uslugihome2:nth-child(odd) {
clear: left;
}
Caution, though, you need to use a polyfill for this to work on older browsers because some pseudo-classes like nth-child are not supported. I recommend Selectivizr.