Lovelace: stack title

I want to create Title for my vertical-stack config:

type: vertical-stack
title: Salon
cards:
  - type: horizontal-stack
    cards:
      - type: entity-button

Unfortunately there is no title showing above stack.

And another question.
Can I change size of stack elements? If I use “light” and “entity button” then both have different sizes. It looks bad:(
And last one question:
How to add theme to Lovelace UI editor? I have only two positions there: “Backend-selected” and “default”. Is there any tutorial?

This would be better posted in configuration. That being said, the core stack cards do not support titles. You could use vertical-stack-in-card as you outer card to accomplish this, I believe, but have not tested.

I use the vertical-stack-in-card as I find it the best way to group together stack panels with a title. It has the added benefit of removing the box-shadows for each of the entities.