The first-indent keyword indicates that the first line of the element is shifted by the expressed amount relative to the other lines in the element. A positive value indicates a shift to the right (i.e. indentation), and a negative value indicates a shift to the left (i.e. an overhanging line). As with indent(), an absolute value (no “+” nor “-” specified) indicates indentation from the left margin. Unlike indent(), a relative value (has “+” or “-”) indicates indentation relative to the rest of the element itself. Since it indicates relative indentation, the first-indent keyword should not be used for elements which only include a single line, since it is meaningless in this context.
The right-indent keyword indicates that the right margin for all lines in the element is shifted to the left by the expressed amount.
A positive indentation will be assumed unless a negative number is specified. Positive indentation is indentation which shrinks the text block; negative indentation is indentation which expands the text block.