message: Tweak dark theme color values
diff: // unified palette
  // try to use these colors when possible
  $bg-color: #181b21;
  -$base-color: #15171b;
  +$base-color: #1b1f25;
  $base-text-color: #edf3ff;
  -$header-panel-bg-color: #181b21;
  -$header-panel-border-color: #1c212b;
  +$header-panel-bg-color: #22262e;
  +$header-panel-border-color: #000000;
  $header-panel-text-primary-color: #a1b2d1;
  $header-panel-text-secondary-color: #c8c8cd;
  $text-primary-color: #edf3ff;
  $text-secondary-color: #a1b2d1;
  -$search-bg-color: #22262e;
  +$search-bg-color: #181b21;
  $search-placeholder-color: #61708b;
  -$room-highlight-color: #22262e;
  +$room-highlight-color: #343a46;
  // typical text (dark-on-white in light skin)
  $primary-fg-color: $text-primary-color;
  