Manipulating the page zoom causes a phantom bar to appear sometimes. In the screenshot below it appears in the middle of the featured chapter section when setting the zoom to 75%:

I've traced it to the header::after style.
@bazzadp any ideas how to mitigate this?
To be honest we could probably just drop this. It was added in an abundance of caution in case the SVG didn't load as then had white text on white background which was obviously unreadable. But as it's base64 encoded to be inlined to the CSS, and as SVG has great support, it's very unlikely it won't be loaded. And the main header.alt-bg class has a couple of fallbacks anyway.
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To be honest we could probably just drop this. It was added in an abundance of caution in case the SVG didn't load as then had white text on white background which was obviously unreadable. But as it's base64 encoded to be inlined to the CSS, and as SVG has great support, it's very unlikely it won't be loaded. And the main
header.alt-bgclass has a couple of fallbacks anyway.