Position fixed doesn't work when using -webkit-transform

Understanding transform's effect on fixed positioning

Applying a CSS transform to an element generates a new stacking context and containing block. This reshaped playground for the child elements can cause a position: fixed element to act like it has position: absolute, making it relative to the transformed parent instead of the viewport.

How to counteract the quirks: Workarounds and their behavior across different browsers

Sticky business: Using position sticky

An alternative is the use of position: sticky;. Although it doesn't emulate position: fixed; entirely, it can similarly appear unaffected by parent transformations:

.sticky-element {
  position: -webkit-sticky;
  position: sticky;
  top: 0; /* or any space your heart desires */
}
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Backgrounds in the Webkit world: Changing the attachment

For background related issues in elements undergoing Webkit transformation, assign background-attachment to scroll:

.element-with-background {
  background-attachment: scroll; // Back to basics: No more sticky business
}
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JavaScript to the rescue: Dynamic adjustments

For browsers where background-attachment: fixed acts temperamental with transform, JavaScript can dynamically adjust background-position:

window.addEventListener('scroll', function() {
  const dy = window.pageYOffset; // Getting your position, like a GPS tracker.
  document.querySelector('.element-with-background').style.backgroundPosition = `0 ${dy}px`; // Now, we keep up with your scrolling. Stalky, but helpful.
});
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Keeping your website snappy: Impact of transformations on performance

Hardware Acceleration and layer creation

CSS transformations induce hardware acceleration, promoting the transformed element to its own compositor layer. But more layers bring along quirks, like issues with position: fixed.

Achieving the equilibrium: Performance and positioning

Striking the delicate balance between performance and correct positioning is crucial. Counter-intuitive as it may seem, separating elements might not always be the best for layer optimization, but ensures position: fixed children are not affected by transitive parent transformations.