Accent Color Fixes
The @theme_selected_*
colors are now aliases
to the libadwaita accent colors variables. This commit
replaces all uses with the corresponding color,
except for the text colors.
@theme_selected_bg_color
is not the appropriate color
to use for colored text. Instead, you should use
@accent_color
which has been tested for proper contrast.
Also keeps the color at full opacity for the selected week.