[gtk] Adwaita: lighten dark switch sliders

[Jakub Steiner <jimmac src gnome org>]

commit 4be2e804aec568027615d2eb9e61e19534cee081
Author: Jakub Steiner <jimmac gmail com>
Date:   Thu Jun 27 10:55:18 2019 +0200

    Adwaita: lighten dark switch sliders
    
    - addresses legibility concerns
    
    Fixes https://gitlab.gnome.org/GNOME/gtk/issues/1819

 gtk/theme/Adwaita/_common.scss           | 18 +++++++++++++++---
 gtk/theme/Adwaita/gtk-contained-dark.css |  4 ++--
 2 files changed, 17 insertions(+), 5 deletions(-)
---
diff --git a/gtk/theme/Adwaita/_common.scss b/gtk/theme/Adwaita/_common.scss
index 49144ed31d..ab32561ac9 100644
--- a/gtk/theme/Adwaita/_common.scss
+++ b/gtk/theme/Adwaita/_common.scss
@@ -2717,12 +2717,24 @@ switch {
     border-radius: 50%;
     transition: $button_transition;
 
-    @include button(normal-alt, $edge: $shadow_color);
+    @if $variant == 'light' {
+      @include button(normal-alt, $edge: $shadow_color);
+    } 
+    @else {
+      @include button(normal-alt, $c: lighten($bg_color,6%), $edge: $shadow_color);
+    }
   }
-
+  
   image { color: transparent; } /* only show i / o for the accessible theme */
 
-  &:hover slider { @include button(hover-alt, $edge: $shadow_color); }
+  &:hover slider {
+    @if $variant == 'light' {
+      @include button(hover-alt, $edge: $shadow_color);
+    }
+    @else {
+      @include button(hover-alt, $c: lighten($bg_color,6%), $edge: $shadow_color);
+    }
+  }
 
   &:checked slider { border: 1px solid $selected_borders_color; }
 
diff --git a/gtk/theme/Adwaita/gtk-contained-dark.css b/gtk/theme/Adwaita/gtk-contained-dark.css
index f417451c56..00b3a81414 100644
--- a/gtk/theme/Adwaita/gtk-contained-dark.css
+++ b/gtk/theme/Adwaita/gtk-contained-dark.css
@@ -1108,11 +1108,11 @@ switch:backdrop:checked { border-color: #030c17; background-color: #15539e; }
 
 switch:backdrop:disabled { color: #5b5b5b; border-color: #202020; background-color: #323232; }
 
-switch slider { margin: -1px; min-width: 24px; min-height: 24px; border: 1px solid; border-radius: 50%; 
transition: all 200ms cubic-bezier(0.25, 0.46, 0.45, 0.94); color: #eeeeec; outline-color: rgba(238, 238, 
236, 0.3); border-color: #070707; text-shadow: 0 -1px rgba(0, 0, 0, 0.834353); -gtk-icon-shadow: 0 -1px 
rgba(0, 0, 0, 0.834353); background-image: linear-gradient(to bottom, #2d2d2d 20%, #262626 90%); box-shadow: 
inset 0 1px rgba(255, 255, 255, 0.02), 0 1px rgba(0, 0, 0, 0.1), 0 1px 2px rgba(0, 0, 0, 0.07); }
+switch slider { margin: -1px; min-width: 24px; min-height: 24px; border: 1px solid; border-radius: 50%; 
transition: all 200ms cubic-bezier(0.25, 0.46, 0.45, 0.94); color: #eeeeec; outline-color: rgba(238, 238, 
236, 0.3); border-color: #111111; text-shadow: 0 -1px rgba(0, 0, 0, 0.786353); -gtk-icon-shadow: 0 -1px 
rgba(0, 0, 0, 0.786353); background-image: linear-gradient(to bottom, #3c3c3c 20%, #353535 90%); box-shadow: 
inset 0 1px rgba(255, 255, 255, 0.02), 0 1px rgba(0, 0, 0, 0.1), 0 1px 2px rgba(0, 0, 0, 0.07); }
 
 switch image { color: transparent; }
 
-switch:hover slider { color: #eeeeec; outline-color: rgba(238, 238, 236, 0.3); border-color: #070707; 
box-shadow: inset 0 1px rgba(255, 255, 255, 0.02), 0 1px rgba(0, 0, 0, 0.1), 0 1px 2px rgba(0, 0, 0, 0.07); 
background-image: linear-gradient(to bottom, #353535 20%, #2b2b2b 90%); }
+switch:hover slider { color: #eeeeec; outline-color: rgba(238, 238, 236, 0.3); border-color: #111111; 
box-shadow: inset 0 1px rgba(255, 255, 255, 0.02), 0 1px rgba(0, 0, 0, 0.1), 0 1px 2px rgba(0, 0, 0, 0.07); 
background-image: linear-gradient(to bottom, #444444 20%, #3a3a3a 90%); }
 
 switch:checked slider { border: 1px solid #030c17; }