Once a box has been laid out according to the normal flow, it may be shifted relative to this position. This is called relative positioning. Offsetting a box (B1) in this way has no effect on the box (B2) that follows: B2 is given a position as if B1 were not offset and B2 is not re-positioned after B1's offset is applied. This implies that relative positioning may cause boxes to overlap.
Relatively positioned boxes keep their normal flow size, including line breaks and the space originally reserved for them. A relatively positioned box establishes a new a new containing block for normal flow children and positioned descendants.