Cart layouts generate standard blocks of HTML. These blocks are merged into your email template at send time through your messaging provider. Because they are standard HTML, they behave like any other part of your responsive template.
To ensure full responsiveness, design your cart layout as part of your overall email template. Use the same layout structure, CSS rules, and media queries you already use elsewhere in your template.
This helps the cart content resize in a predictable way across devices and email clients. In most cases, you do not need to apply any special Fresh Relevance–specific settings. Treat the cart layout content exactly like the rest of your HTML.