JSFiddle - React, Tailwind, and code Playground

HTML

<div class="mgu-teaser-slide-left mgu-rot">
    <div class="mgu-teaser-slider-bubble">blabla</div>
</div>
or
<div class="mgu-teaser-slide-left mgu-gelb">
    <div class="mgu-teaser-slider-bubble">blabla</div>
</div>

CSS

.mgu-rot {
	background: red;
}

.mgu-gelb {
	background: yellow;
}

.mgu-teaser-slider-bubble {
	background: transparent;
}

.mgu-teaser-slide-left.mgu-gelb .mgu-teaser-slider-bubble {
	background: pink;
}