Function glass_selected_bg 

pub fn glass_selected_bg() -> Hsla

Selected-state glass treatment (tabs, session rows, space rows): ../desktop’s --color-active — white at 12% on dark, black at 6% on light, translucent enough for the vibrancy to read through (heavier flat washes blocked the glass, user request).

One rung over Theme::element_hover, carrying the ring in glass_selected_shadows on top. Selection inside floating cards is card_selected_bg.