The :global() pseudo-class in Vue scoped SFC styles was being mangled
by the Vue compiler, producing broken CSS that applied properties like
z-index and opacity directly to the <html> element and dropped the
intended component selectors entirely.
Replace the html[data-mouse-active] / html[data-pointer-visible] data
attribute approach with plain CSS classes (mouse-active, pointer-visible)
toggled on document.documentElement. In Vue scoped styles, prefixing a
selector with html.mouse-active or html:not(.mouse-active) compiles
correctly — the html part stays global while the component selector
receives the scoped attribute — avoiding :global() entirely.
This keeps all component styles inside <style scoped> and fixes the
layout breakage caused by the original commit.