css sticky card with masked content

hello hello I'm trying to do something with css only, but I'm failing 😄 I want a sticky section, I scroll to this, the map and card gets pinned, then the content inside of the card is scrolling (the groups with headlines and logos) my main issue is/was that I need the parent of the pinned card to have the height of the content for it to work, so I thought I make the card a sibling of the content, and while this works, the content obviously is not clipped then, it looks like in the codepen would love to get any sort of input, demos, tutorials, ideas ... https://codepen.io/flavaflo/pen/goLMvR

Flo Suesstrunk

CodePen

sticky device mask

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