reveal.js/css/theme/template/mixins.scss

@mixin light-bg-text-color($color) {
	section.has-light-background {
		&,
		h1,
		h2,
		h3,
		h4,
		h5,
		h6 {
			color: $color;
		}
	}
}

@mixin dark-bg-text-color($color) {
	section.has-dark-background {
		&,
		h1,
		h2,
		h3,
		h4,
		h5,
		h6 {
			color: $color;
		}
	}
}