Responsive wrapper

Hello,
I write this in my CSS so the images in my slider will be responsive.

.promo_slider {
		max-width: 100%;
		height: auto !important;
		position: relmative;
		border: red 1px solid;
		overflow: hidden;
	}
		.promo_slider img{
		max-width: 100%;
		height: auto;
	}

It works pretty well but my slider nav are out the image on mobile devices because the height: auto !important; property is not overriding the height of the propotion slider wrapper.
The images are greatly scaled but the wrapper keeps the height of desktop media.

Please check this website on a mobile or with screenfly to see what is my issue.

https://www.ads-software.com/plugins/promotion-slider/