docs/style.css

#content > h1:first-of-type {
  display: none !important;
}

.nav-tabs {
  position: relative;
}

.nav-tabs-item > div {
  opacity: 0;
}

.nav-tabs-underline {
  position: absolute;
  left: 0;
  bottom: 0;
  height: 1.5px;
  width: var(--nav-tab-underline-width, 0);
  transform: translateX(var(--nav-tab-underline-x, 0));
  background-color: rgb(var(--primary));
  border-radius: 999px;
  pointer-events: none;
  opacity: 0;
  transition:
    transform 260ms ease-in-out,
    width 260ms ease-in-out,
    opacity 160ms ease-in-out;
  will-change: transform, width;
}

html.dark .nav-tabs-underline {
  background-color: rgb(var(--primary-light));
}

.nav-tabs-underline-ready .nav-tabs-underline {
  opacity: 1;
}