Created attachment 430242 [details] demo code Running Safari Version 14.0.3 (16610.4.3.1.7) https://jsfiddle.net/suda14q3/ I have a flexbox with justify-content:space-between. One of its descendants (.parent_right) has two children: .ch1 (gold), .ch2 (lime), both 100px wide. When I resize the webpage down past 500px, I trigger a media query, which sets position:absolute to .ch1. Safari doesn't seem to update .parent_right's width and it looks like its still takes 200px of space. If I now reload the webpage, everything will look fine (.parent_right 100px wide because .ch2 is 100px wide and .ch1 is positioned absolute) I will resize the window back up to 500px+ and another bug occurs: children of .parent_right take up 50px each. --- Expected behavior: When resizing down: .ch1 is moved to the top of .ch2, no space is left to the right of them. .parent_right takes 100px; When resizing back up: everything returns back to initial state I'm sorry if this explanation is clumsy, not a native speaker. I can record a video of the bug if needed.
<rdar://problem/78993605>