I have this layout:
Can you share what output you expect? Meanwhile you can try this for max-width calc((100vmin * 2 / 3) + 200px).
calc((100vmin * 2 / 3) + 200px)
For padding, you can add box-sizing: border-box; so it doesn't add additional height to specific height. See if it helps.
box-sizing: border-box;