Vertical-container does not work after Poseidon Theme Upgrade

[ahmetsaimyilmaz]

We have upgraded our poseidon theme from 4.0.0 to 6.0.0. I have a panel where items are listed in vertical order using <div class="p-grid p-align-stretch vertical-container">. After the upgrade it has no effect and listed horizontally. Looked in the theme.css folder but found no code related to vertical-container. How can I overcome this issue ? Thanks for the help