Is it possible to do something like this
max-width: calc(max(500px, 100% - 80px))
or
max-width: max(500px, calc(100% - 80px
A 'pure' css solution actually is possible now using media queries:
.yourselector { max-width: calc(100% - 80px); } @media screen and (max-width: 500px) { .yourselector { max-width: 500px; } }