In CSS, all things are possible:
div.tr-group:nth-child(odd) {
filter: brightness(85%);
}
Tune as needed.
Note:
This only works as long as a color is applied. If no color is applied, there is nothing to adjust the brightness of.

In CSS, all things are possible:
div.tr-group:nth-child(odd) {
filter: brightness(85%);
}
Tune as needed.
Note:
This only works as long as a color is applied. If no color is applied, there is nothing to adjust the brightness of.
