:root{
--sidebar-hover-width: 8px;
--sidebar-visible-width: 300px;
}
#sidebar-box #sidebar {
min-width: var(--sidebar-hover-width) !important;
width: var(--sidebar-hover-width) !important;
max-width: var(--sidebar-hover-width) !important;
opacity: 0 !important;
position: absolute !important;
display: block !important;
}
#sidebar-box:hover #sidebar {
min-width: var(--sidebar-visible-width) !important;
width: var(--sidebar-visible-width) !important;
max-width: var(--sidebar-visible-width) !important;
opacity: 1.0 !important;
}
#sidebar-box #sidebar-header {
visibility: collapse !important;
}
#sidebar-box:hover #sidebar-header {
visibility: visible !important;
}
#sidebar-box {
z-index: 1000 !important;
-moz-margin-end: calc(-1 * var(--sidebar-hover-width)) !important;
position: relative !important;
opacity: 0 !important;
}
#sidebar-box:hover {
-moz-margin-end: unset !important;
opacity: 1.0 !important;
}
#sidebar-box ~ #appcontent {
-moz-margin-start: calc(-1 * var(--sidebar-hover-width)) !important;
}
#sidebar-box:hover ~ #appcontent {
-moz-margin-start: calc(-1 * (var(--sidebar-visible-width) + var(--sidebar-hover-width))) !important;
}
Cette contribution était de : http://www.gratilog.net/xoops/newbb/viewtopic.php?forum=9&topic_id=16278&post_id=195874