Change font color of the subtitle in ioslides' cover

Question

I would like to change the color of the subtitle in my ioslides very first slide (the cover). I managed to change the color, size, etc of the title, as well as the Author and Date.

However, I do not know how to deal with the subtitle. This is my YAML:

---
title: "My title"
subtitle: "How can I change the color of the subtitle"
author: "Mario Modesto-Mata"
date: "18 février 2019"
output:
  ioslides_presentation:
    css: estilos.css
    smaller: yes
    transition: slower
    widescreen: no
---

This CSS is for author and date:

slides > slide.title-slide p {
  color: red;
}

And this for the title:

slides > slide.title-slide hgroup h1 {  color: red;
  font-size: 60px;
  letter-spacing: 10;
}

What about the subtitle?

Answer 1

I managed to solve by myself. By selecting h2 in the slide.title-slide we can modify whatever we need.

slides > slide.title-slide hgroup h2 {  
  color: red;
  font-size: 30px;
  letter-spacing: 10;
}