Introduce semantic theme variables (e.g. --color-success, --color-danger,
--color-warning, --color-info) and a set of overlay/tint/shadow variables
(--app-hover-tint, --app-raise-tint, --app-soft-tint, --app-overlay-shadow,
--app-menu-shadow, --app-float-shadow, etc.) and use them throughout
app.css in place of many hard-coded color, background and shadow values.
This change:
- replaces literal color tokens used for badges, pills, buttons, menus,
toasts, borders and file icons with the new semantic variables
- switches several box-shadow and overlay usages to the new shadow vars
- harmonizes light-theme surface, border and scrollbar values to explicit
variables for easier maintenance
No structural or behavioral changes; this is purely a visual/theming
refactor to make future theme adjustments and dark/light parity simpler.
Christoph