.root { background-color: var(--theme-color-background-chat); display: none; --header-h: 64px; } @media (min-width: 768px) { .root { position: sticky; top: var(--header-h); display: block; height: calc(100vh - var(--header-h)); max-height: calc(100vh - var(--header-h)); } } /* First div is .ant-layout-sider-children Only way to target it apparently */ .root > div { display: flex; flex-flow: column nowrap; -moz-box-flex: 1 !important; flex-grow: 1 !important; height: 100% !important; }