GTK CSS, and defines the missing colors referenced)
SwayNC style.css (uses the same @define-color values and the same @base
background; also fixes card_rgba typo)
Note: Blur is not a CSS thing here — SwayNC is GTK-based, so
backdrop-filter is not reliably supported. Do blur via Hyprland
layerrule. SwayNC is explicitly a GTK notification center.
henrov