Pending requirement:

With a small viewport, the header must be accessible. Normally you would want to create a sidebar or a dropdown menu for mobile devices but for this exercise it is enough to simply allow the overflowing links to wrap.

Pending requirement:

With a small width i.e. from a mobile device, the content of the cards must be readable. Make sure that the card width can become as small as required so that no scrolling is required on a 320px wide screen.
Do not change the appearance on large screens!

Pending requirement:

With a small height i.e. when using the website from a phone in landscape and an open keyboard, the input must be visible. That means that the navigation bar must un-fix itself from the top.