Edit: Found a solution, if anyone else needs it…
I had the following custom CSS from a post by David on another thread. All I needed to add was ‘–gp-slideout-width: 500px!important;‘ to the root, to override the default width (which is where my off-canvas panel was stopping briefly on closing the menu).
/* desktop width */
:root {
--slideout-width: 500px;
--gp-slideout-width: 500px!important;
}
/* small device width */
@media(max-width: 768px) {
:root {
--slideout-width: 100%;
}
}
#generate-slideout-menu.main-navigation.offside {
width: var(--slideout-width);
}
#generate-slideout-menu.main-navigation.offside--left {
left: calc(-1 * var(--slideout-width));
}
#generate-slideout-menu.main-navigation.offside--left.is-open {
transform: translate3d(var(--slideout-width), 0, 0);
}