Why the Cart and Checkout page of woocommerce are not fit for mobile device(RWD)?

I have Sydney pro theme, why the Cart and Checkout page of woocommerce are not fit for mobile device(RWD)? It looks very unfriendly for portable device. How can I do for these page as RWD? Thanks.

Hello there,

Have you checked our shop demo? Does it look different with yours?

Please share a link to your site, so I can have a look.

Regards,
Kharis