The coordinates for the section element need not be defined as long as its position is set to

a.) static
b.) fixed
c.) relative
d.) absolute

The coordinates for the section element need not be defined as long as its position is set to c.) relative.

If the position is set as relative, then it will have no effect on the positioning attributes, it will consider as static position. If positioning is mentioned explicitly like top: 20px; then it will position 10 pixels down from where it is located. An ability for positional shifts is extremely helpful.

Two things happen when an element is set as relative, one is it introduces the ability to use z-index on that element, second is it limits the scope of absolutely positioned child elements.  

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