Hello Ion,
Sorry for a late reply. There are several areas to be changed.
You can start with this code:
button,
input[type="button"],
input[type="reset"],
input[type="submit"],
.button,
.more-link,
.page-footer .post-edit-link,
.wp-block-button__link:not(.has-background),
.wp-block-file .wp-block-file__button:not(.has-background),
.wp-block-getwid-media-text-slider .slick-prev, .wp-block-getwid-media-text-slider .slick-next
{
background-color: #808080;
}
Let me know if it helps.
Regards,
Steve.