fix(libadwaita): view background darker than sidebar (This solved #519) (#536)

Author: hthienloc

src/Mint-Y/libadwaita-1.5/defaults-dark.css

@@ -21,7 +21,7 @@
 @define-color error_color #ff7b63;
 @define-color window_bg_color @mint_header;
 @define-color window_fg_color white;
-@define-color view_bg_color #2e2e33;
+@define-color view_bg_color #1d1d20;
 @define-color view_fg_color white;
 @define-color headerbar_bg_color @window_bg_color;
 @define-color headerbar_fg_color white;

src/Mint-Y/libadwaita-1.7/defaults-dark.css

@@ -18,7 +18,7 @@
 @define-color error_color oklab(from @error_bg_color max(l, 0.85) a b);
 @define-color window_bg_color @mint_header;
 @define-color window_fg_color white;
-@define-color view_bg_color #2e2e33;
+@define-color view_bg_color #1d1d20;
 @define-color view_fg_color white;
 @define-color headerbar_bg_color @window_bg_color;
 @define-color headerbar_fg_color white;