Only display sale price while hiding regular price at the top of product pages

Example before:


Note: This will affect all products including regular priced items - The top price will not be shown on a product that's at regular price:


/* -- code to hide top regular price on product pages -- */
#ProductPrice-product { display : none; }
.template-product .product__price { margin-bottom : 30px; }
/* - end - */

Where do I add the code?

Use this link to learn where exactly to add this code snippet:

Where to add your CSS style code