.menu_principal_visible {
  top: 0!important;
  visibility:visible!important;
}

.overflow-0 {
  overflow: hidden!important;
}

/*
by default, overlay is visible…
*/
.offcanvas2 {
  /*height:100vh!important;*/
  height: calc(100vh - 62px);
  overflow-y: scroll;
  position: fixed;
  visibility: hidden;
  z-index: 1019;
  top: 0; right: 0; bottom: 0; left: 0;
  /* fix text transition issue for .left and .right but need to overwrite left and right properties in .right */
  width: 100%;
  -moz-transition: top 0.3s, right 0.3s, bottom 0.3s, left 0.3s;
  -webkit-transition: top 0.3s, right 0.3s, bottom 0.3s, left 0.3s;
  transition: top 0.3s, right 0.3s, bottom 0.3s, left 0.3s;
}
/*
…but this hide it
*/
.offcanvas2-top {
  top: 100%;
}