Print Dialog Responsive on Mobile Devices

[1Map]

How can the print parameters settings panel (Left panel) be collapsed/expanded (Responsive) when on mobile devices?

[Viglino]

You can use CSS and and media query to make it more responsible.
The current CSS only change the width of the panel:

@media (max-width: 25em) {
    .ol-ext-print-dialog .ol-print-param {
        width: 13em;
    }
}
@media (max-width: 25em) {
    .ol-ext-print-dialog .ol-print-map {
        width: calc(100% - 13em);
    }
}

You can add a button to toggle the panel using getUserElement (or getContentElement):

var bt = document.createElement('BUTTON')
bt.innerText = 'ok'
printControl.getUserElement().appendChild(bt)