Sticky Text won't stop until end of the website

Question

I try to make my text sticky in a specific section from my Website but the text won't stop until it reach the footer. So please can someone have a look on my shitty Code and give me a solution for the problem?

I use Yootheme which works with Ulkit 3.

<div>
  <div class="uk-card uk-text-center uk-position-z-index" uk-sticky="end: !.uk-height-xlarge; offset: 340" uk-sticky="media: 1020">Customer Voices </div>

Ulkit 3

div {
     font-size: 35px;
     z-index: 0;
}

<div>
  <div class="uk-card uk-text-center uk-position-z-index" uk-sticky="end: !.uk-height-xlarge; offset: 340" uk-sticky="media: 1020">Customer Voices </div>
</div>