message: Fix toolbox section header text visibility
diff: background-color: var(--activating-background);
  font-weight: bold;
  border-top: 1px solid var(--deep-background);
  - color: rgba(250,250,250,.2);
  + color: #989898;
  fill: rgba(250,250,250,.2);
  }
  .cs-toolbox-section.closed > header:hover {
  background-color: var(--active-background);
  - color: rgba(250,250,250,.5);
  + color: #d6d6d6;
  fill: rgba(250,250,250,.5);
  }
  