Ok, so the idea is that any item in the component can be a button, a link or anything, for instance another custom element. For that reason we do not want to style those items ourselves inside the component as the external styles do apply to slotted elements. This PR adjusts a couple of things:

• It brings the consumed CSS variables declarations and fall on the top of the scss file (I have seen this pattern in Ionic quite often and kinda like it because you have a nice overview and it simplifies all the rest of their usage instead of callback declared on each usage).
• It removes the added styles in the scss file
• It removes the --text-color customization as really it did not apply anyway, slotted content uses the styles defined externally
• It adjusts the story for a better example of usage with custom slotted content with their own styles, which might be easier to figure out how to use.