Hi Joe,
the general tip for Custom CSS is: https://www.joomshaper.com/documentation/helix-framework/helix-ultimate-2/custom-code-css-js-meta
using custom CSS you have to make of those changes, below is FREE example code:
#sp-main-body {background-color: transparent;}
#sp-component {background: #A4A6A5;border-radius: 10px;}
#sp-left .sp-module, #sp-right .sp-module {
background: #E3E3E3;
border-radius: 10px; padding: 10px;}
#sp-header, #sp-header.header-sticky {
border-radius: 10px;}
it's typical customization job, beyond support.