Code to remove space between Heading and Paragraph

Site URL: https://www.samadihealing.com/

Hi There 🙂

I found this post on the Squarespace forum 

https://forum.squarespace.com/topic/80891-how-to-reduce-space-between-different-text-styles-in-same-text-block/

I'd like to try the second fix (beatrizc) but it seems I might be missing part of the code? Does anyone know how I can make this work 

Thanks in advance!

Add to Home > Design > Custom CSS

.sqs-block h3 {
    margin-bottom: 0;
}