Thanks! Figured it out.
I added this code to my php so I could assign a custom css class to individual elements:

add_theme_support(‘avia_template_builder_custom_css’);

Then added this code in the quick css box after assigning classes to the 3 elements I wanted to shrink:

@media screen and (max-width: 800px) {
.yourclass {
display: none !important;
}
}