Specify measurement units used in the generated HTML.
This applies to font sizes and most of length values (like spacing, margins, paddings etc.), which are specified as properties of CSS rules generated directly from the formatting properties of template components and template formatting styles.

Note: A few length values are always specified in pixels (e.g. border width), because otherwise their effect would be highly unpredictable.

Possible Values:
"relative"
This is the default setting. All font sizes are specified in percents relatively to the document base font size (determined by the HTML browser). Other things like spacings, margins, paddings etc. are set in em units, which are also interpreted against the base font size.

All values are computed from the corresponding formatting properties specified in templates according to the following formulas (for em and % values correspondingly):

valuetpl / defaultFontSizetpl
(valuetpl / defaultFontSizetpl) * 100
where
valuetpl  -  the property value specified in the template
defaultFontSizetpl  -  the template default font size, which it is one provided by the default paragraph style in the main template
Relative units are considered most convenient for viewing HTML documentation in web-browsers. However, there is one problem. According to CSS, the effective value of a CSS property specified in relative units is actually computed against the font size inherited from the parent element where the property is applied. This creates the problem of compounding, which requires special efforts to work around. For more details, see The problem with relative length units.
"pixels"
All font sizes, spacings, margins, paddings etc. will be set in pixels (px).

These values are produced from the corresponding formatting properties specified in templates according to the formula:

(valuetpl / defaultFontSizetpl) * baseFontSizepx
where
valuetpl  -  the property value specified in the template
defaultFontSizetpl  -  the template default font size, which it is one provided by the default paragraph style in the main template
baseFontSizepx  -  the value of "Units | Base font size" option for pixels
"points"
All font sizes, spacings, margins, paddings etc. will be set in points (pt).

These values are produced from the corresponding formatting properties specified in templates, which are typically set in points too. But the point values that get in the generated HTML (i.e. CSS rules) are not exactly the same as those specified in templates. Rather, they are computed according to the formula:

(valuetpl / defaultFontSizetpl) * baseFontSizept
where
valuetpl  -  the property value specified in the template
defaultFontSizetpl  -  the template default font size, which it is one provided by the default paragraph style in the main template
baseFontSizept  -  the value of "Units | Base font size" option for points
${include css_usage_link.htm}