Darkening of main image

I love this theme… just started to implement, so far just one small thing I would request… can the percentage of the darkening of the main image be customized? I will play a little bit with augmenting the contrast of the original picture, if that doesn’t work, I will go through the code to change the percentage value… but, I am guessing other people might be interested in this enhancement as well.

It’s at 90% at the moment.
Add this in a custom CSS plugin or child theme and adjust the 0.9 value as needed:

.header-image::after {
    background-color: rgba(37, 46, 53, 0.9);

Is this customization ready yet?