[css3-values] A new bases for relative unit sizing

In CSS, there needs to be a way to specify the specific element you want to
base your relative sizing units off of. Relative sizing units shouldn't
necessarily be based on a parent element's size, or the page's size, or the
viewport. A web module may have numerous child-elements of various depths,
and the element you want to base relative sizing units off of might not be
an immediate ancestor!

For example, please take a look at the question I posted here:
https://programmers.stackexchange.com/questions/271779/how-to-make-scalable-modules-in-a-div-element

I like how the viewport units allow you to scale the contents of a page. I
made this page, and am happy that even the fonts are scaling well on it:
http://www.lonniebest.com/emailform/

However, my ultimate goal is to be able to create composite web-modules
(that are encapsulated by one div element, for example) that can be placed
onto any web-page in a manner that a webmaster can scale that element's
contents just by simply setting the divs height and width. To do this, I
really need relative sizing units to be base on a particular element -- the
one that encapsulates
my entire web-module.

To some degree, this can be achieve with % units, but not for font-size! I
have not found a relative font-size unit that can be based on the size of a
parent element. If a webmaster put my self-made module onto his page, my
font-sizes will be based on this size of his page, and NOT base on the size
he decided to set my module.

Viewport units work great if you web-module is the size of the viewport;
resizing the window makes even fonts re-size proportionately.

The web is getting very close to offering the same scalable modules of
non-web technologies such as QML and WPF.

If CSS could offer a way for a webmaster to "specify a particular element
that relative sizing units are to be base on", this seems perfect.

Again, a web module may have numerous child-elements of various depths, and
the element you want to base relative sizing units off of might not be an
immediate ancestor and it might not be the page as whole. For a web module,
you want relative size of fonts and everything else to be based on that
module's size (not the page as a whole).

CSS should be so flexible, that I can create an independent module and you
can put it onto you page, and by simple setting my modules height, width,
and location: everything contained in that module scales proportionately to
your environment. If you make the size of my module super small, the fonts
should be super small, not based on the page as a whole.