docs-v2/assets/styles/sidebar-open.scss

// Default state of having the sidebar open.

.sidebar {
  transition: all .2s;
  .search-and-nav-toggle,
  #nav-tree {
    opacity: 1;
    transition: all .3s;
    transition-delay: .1s;
  }
}

.search-btn {
  opacity: 0;
  width: 0;
  overflow: visible;
  transition: opacity .2s, width .2s .2s !important;
}