Hi Dylan, thank you for your question!
There are some default styles applied to new widgets in the Resolve theme that unfortunately do not have explicit controls to change them in the Customizer. However, you can modify how your widgets display by using some custom CSS. This snippet will remove the borders from your widgets in addition to removing the background color and box shadows, if you need to do that as well.
.palette-primary .well {
background: transparent;
border: none;
box-shadow: none;
}
I hope that helps you get your widgets styled correctly and please let us know if there is anything else that we can do to help!