Payment icons - Change from color to black and white

Pipeline 4.2 introduced Shopify's new payment icons in colour. If you'd like to change the coloured icons back to black and white, you can use this quick modification. 

Example new icons:

Change to black and white:


/* -- code to change payment icons to black and white -- */
svg.payment-icon { filter: grayscale(1); }
/* - 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