message: fix sidebar nav color affected by main section style
diff: }
  // General (Nav)
  - .uk-nav-default .uk-nav-header {
  + .uk-nav-default:not(.left-nav) .uk-nav-header {
  color: @dark-mode-text-3;
  }
  - .uk-nav-default .uk-nav-divider {
  + .uk-nav-default:not(.left-nav) .uk-nav-divider {
  border-top-color: @dark-mode-background-1;
  }
  - .uk-nav-default > li > a {
  + .uk-nav-default:not(.left-nav) > li > a {
  color: @dark-mode-text-4;
  }
  