I searched here but found nothing about it.
Several clients have asked me about buttons with the "btn-warning" class. So I did some tests with other colors and, in my opinion, the condition:
@if ($ yiq> = 150) {
would have a better result if the conditional value were changed to:
@if ($ yiq> = 195) {

Here are some examples below:

But I also believe this to be a personal opinion. In this way, we could consider a variable for this value. I think we'd shut the functionality down.
Well, I think it's a simple change and it's going to have a positive impact.