Size (fontSize)
The Size property sets the font size in points for a node and for all children of the node.
In the Properties view, this property is the Size property in the Font category.
During expression evaluation the variable fontSize is available, which contains the inherited font size. This variable can be used for relative font sizing. For example, the expression fontSize="fontSize*1.2" makes the current font 20% larger than the parent font.
Type: Numeric. The default value (not the expression) is inherited from the parent. The root node has a font size of 12 point.