actuel-inactuel/assets/css/src/tabs.css

.toggle-btns {
  position: sticky;
}
button.toggle.open {
  font-weight: bold;
}

button.toggle.left::after {
  margin-left: var(--unit--horizontal);
}
button.toggle.left.close::after {
  content: "+";
}
button.toggle.left.open::after {
  content: "-";
}

button.toggle.right::before {
  margin-right: var(--unit--horizontal);
}
button.toggle.right.close::before {
  content: "+";
}
button.toggle.right.open::before {
  content: "-";
}

#tabs {
  position: relative;
}

.active-tab {
  position: absolute;
  overflow: auto;
  margin-top: calc(var(--unit--vertical) * 0.5);
  height: 0px;
  transition: height 0.5s ease-in-out;
}

.page-cover.open .active-tab {
  height: calc(100vh - 7.5 * var(--unit--vertical));
}