'transform3d' not working with position: fixed children

Decoding the issue

The uncanny behavior exhibited when a position: fixed element is nestled inside a transformed parent arises from the formation of a local coordinate system. This spatial shift tends to defy the positioning expectations we usually have for fixed elements.

Restructuring for Resolution

Positioning elements with fixed attributes relative to a transformed ancestor can lead to visual discrepancies. In order to maintain visual harmony and respect the laws of the element hierarchy, it's crucial to be mindful of spatial relationships when drafting your HTML structure.

JavaScript Assistance

If you find that restructuring your code doesn't jive with your layout requirements, JavaScript could be the hero you need. By dynamically adjusting the fixed element's position based on scroll events, you can keep your layout in check.

$(window).on('scroll', function() {
  $('.fixedElement').css({
    top: $(window).scrollTop(),
    position: 'fixed' // "Stick around." - An unappreciated pun by every position: fixed element ever 😉
  });
});
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Remember, with great power (of continuous DOM manipulation) comes great responsibility (to mind performance implications).

The Sticky Position

Not quite fixed, not quite relative. Meet: position: sticky. This balance walker might deliver similar results to fixed positioning while playing nicer with transformed parents. However, not all web browsers invite sticky to the party, leaving you to handle the eccentricities and constraints on your own.

Positioning Alternatives

Sometimes the solution lies in thinking outside the box, or in this case — div. Using translate3d inside a fixed wrapper can grant you the positioning prowess you seek.

.fixedWrapper {
  position: fixed;
  transform: translate3d(var(--x), var(--y), var(--z)); // "To infinity, and beyond!" - Buzz LightCSS
}

.divInside {
  transform: translate3d(0, 0, 0); 
}
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Stabilising Element Motion

Applying translateZ(0) to the element helps with flickering issues and improves rendering performance. It won't fix any position misalignment but it'll make the visual output more stable.

.fixedElement {
  transform: translateZ(0); // "Please fasten your seatbelts. We're entering 3D space" - Every Z-axis
}
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Cross-browser compatibility is always a game we play. The -webkit-transform will ensure your bases are covered.

.fixedElement {
  -webkit-transform: translateZ(0);
  transform: translateZ(0);
}
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Event-Driven Adjustment

Tying position adjustment to the browser's scroll event helps in maintaining alignment irrespective of parent transformations.

window.addEventListener('scroll', function() {
  var yPos = Math.max(0, $(window).scrollTop()); // "You can't scroll past me!" - DOM Element Meme
  $('.fixedElement').css({
    top: yPos + 'px'
  });
});
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HTML Restructuring: Last Resort

An extensive use of transform3d properties calls for alterations in your DOM structure and styling. It might be a bit painful but remember: no pain, no gain.