.xfce4-panel
  .tasklist

  #whiskermenu-button
  #xfce4-notification-plugin
  #xfce4-power-manager-plugin
  #pulseaudio-button
  #clock-button

  wnck-pager

Panelbar background color.

  .xfce4-panel.background {
    background-color: rgba(36, 36, 36, 0.8); }

Tasklist toggle button background colour, text color, and border radius.

  .tasklist .toggle {
    background-color: lightblue;
    color: black;
    border-radius: 3px; }

Panelbar tasklist button

Whisker Menu panel button.

  #whiskermenu-button label {
    color: lightblue;
    font-weight: bold;
    font-style: italic; }

Whisker Menu panel button

Pulseaudio menu mpris buttons.

  #pulseaudio-button menu .linked button {
    color: lightblue;   /* This will apply a colour to the mpris button icons */
    border-color: gray; }  /* This will apply a cololur to the mpris button border */

Pulseaudio menu MPRIS buttons

*The pulseaudio menu contains common GTK widgets such as a scale, trough, switch, and slider.*

Workspace switcher colours for selected and active states.

  wnck-pager:selected {
    background-color: lightblue; }
  wnck-pager:hover {
    background-color: gray; }

Panelbar workspace switcher