Hi! That's correct - bookmarks are stored locally on your device, in the browser itself, not on your account. So bookmarks you save on your phone will stay on your phone, and bookmarks you save on your computer will stay on your computer. They don't sync between devices automatically.
We do it this way on purpose: it keeps the site fast and it means we don't store any of your data on our servers. The downside is exactly what you've noticed - each device keeps its own list.
If you only have a handful of bookmarks, the quickest fix is to simply bookmark them again on your computer - it takes seconds.
If you have a lot of them, your bookmarks page has a JSON download option: save the file, send it to yourself (email works fine), then import it on your computer and your whole list will appear there. It's also a good idea to keep that file saved somewhere safe as a backup, just in case.
Hope that helps!
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