URGENT help with code

Site URL: https://tangerine-chrysalis-dzdj.squarespace.com/

Site URL: https://tangerine-chrysalis-dzdj.squarespace.com/

password for site 123

This this the code I have for a custom slide show carousel.
I want to edit the maximum height for the image.
Anyone know what I can add to this code to change it?
I need it to be half the height it is right now.

THANK YOU!

<div class="hero-slider" data-carousel>
  <div class="carousel-cell" style="background-image:url(https://static1.squarespace.com/static/5f11c3a07344661ba3b05678/t/5f7c8c6096cbcb0e9d171437/1601997920873/test.jpg);">
    <div class="overlay"></div>
    <div class="slide-content">
      <div class="mask">
        <h2 class="title">"Amazed how much more effective I became at looking and seeing, so I feel like the vitual online training helped me even more to train my eye to look at the body as a whole!"
</h2>
      </div>
      <div class="divider"></div>
      <div class="mask">
        <p class="caption">-Jessica Fritz-Peters,Owner and Director, Pilates Defined</p>
       <!-- <a href="https://flickity.metafizzy.co/" target="_blank" class="btn">Tell me more</a> -->
      </div>

 Add to Home > Design > Custom CSS

.hero-slider {
    height: 50vh;
}