How can I edit Seal Subscriptions code for table layout in Shopify?

I’m trying to edit the table with the three radio buttons installed by Seal Subscriptions to change the borders and fonts of the table. Using the inspect feature on my browser, I found the solution was in this code.

.sealsubs-container .sls-purchase-options-container .sls-option-container, .sealsubs-container .sls-purchase-options-container .sls-option-container.sls-active {
border: none;
border-bottom: 1px solid rgba(198, 198, 198, 0.55);
/* border-bottom: 1px solid rgba(198, 198, 198, 0.55); */
padding: 1em 0.75em;
border-radius: 0;
}

Would I be able to access the sealsubs div files in the Shopify code editor, if I would be able to at all.