dots/usr/share/themes/Dracula/gtk-3.20/apps/_thunar.scss

/* thunar */
.thunar toolbar {
    background-color: $headerbar_color; 
  }
  
  /* buttons in toolbar */
  .thunar toolbar.horizontal button image {
    -gtk-icon-transform:scale(0.72);
  }
  
  scrolledwindow.sidebar treeview.view, scrollbar.right {
    background: $sidebar_bg_color;
    padding: 2.5px 1.5px;
    border: none;
    box-shadow: none;
  }

  scrolledwindow.standard-view scrollbar.right{
    background-color: $base_color;
  }
  /* path-bar of thunar */
  window.thunar toolbar > toolitem > widget > widget.linked.path-bar > button.toggle.path-bar-button, .thunar  scrolledwindow.sidebar treeview.view,  .thunar toolbar.horizontal button {
    &:hover, &:checked, &:selected{ 
        @include button(active-header, $tc: $purple);
        font-weight: normal;
    }

    &:checked:backdrop, &:selected:backdrop {
        label { color: $backdrop_selected_bg_color; }
    }
  }
  
  window.thunar toolbar > toolitem > widget > widget.linked.path-bar > button.path-bar-button {
    background: none;
    outline: none;
    border: none;
    box-shadow: none;
  }