How to dynamically change font size using loop or replace macro?

For example:

<<set $value = $value + 1>>
<<repeat 1s>>
<span id = fontincreaser> 

</span>>
<<replace #fontincreaser>>
@@font-size: $value em; Font gets bigger@@
 OR
@@font-size: $value %; Font gets bigger@@
<</replace>>
<</repeat>>

Also how come I can't get my setterlinks to go to the variable passage name, for example:
<<set $variablepassagename = "cave">>
[[$variablepassagename]]
When clicked, link takes you to to passage named $variablepassagename and not passage named cave.

A workaround I found was <<goto $variablepassagename>> which takes you to a passage named "cave".