: Text color.</li>
  <li><code>foregroundButtonOn</code>: Text color of active toggle
  button. Recommend to use the same value of <code>foreground</code> or
  <code>boxBackground</code>.</li>
  <li><code>foregroundInactive</code>: Text color of inactive
  components. Currently, only used for TabView.</li>
  <li><code>background</code>: Background color.</li>
  <li><code>boxBackground</code>: Background color of inside of box
  shaped components (Barbox, Button, Checkbox, OptionMenu, TextKnob,
  VSlider).</