A space defines a size or position that can be either relative or absolute on either axis.

<Node Space="12%"/>
<Node Space="14.2%, 13"/>
<Node Space="15.75"/>
<Node Space="15.75, 13"/>

If one value is given, uses that value for both the X and the Y. If two values are given, uses them for the X and Y respectively, separated with the , character.

If a value ends with a % character, it will be treated as relative for that axis.