[gtk+] HC: Add border/hilight when hovering flat buttons

[Daniel Boles <dboles src gnome org>]

commit fbf24d1bd070280299e30db87d8f92aef9e5bb69
Author: Daniel Boles <dboles src gnome org>
Date:   Fri Oct 6 02:32:37 2017 +0100

    HC: Add border/hilight when hovering flat buttons
    
    The border and icon highlight are useful feedback that was defeated by
    CSS precedence. It worked for .titlebuttons due to their implementation,
    but the same was not true for custom .flat buttons. This makes it so.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=788580

 gtk/theme/HighContrast/_common.scss              |    3 ++-
 gtk/theme/HighContrast/gtk-contained-inverse.css |    2 +-
 gtk/theme/HighContrast/gtk-contained.css         |    2 +-
 3 files changed, 4 insertions(+), 3 deletions(-)
---
diff --git a/gtk/theme/HighContrast/_common.scss b/gtk/theme/HighContrast/_common.scss
index a1ed2c8..e21a20a 100644
--- a/gtk/theme/HighContrast/_common.scss
+++ b/gtk/theme/HighContrast/_common.scss
@@ -409,7 +409,8 @@ button {
       }
     }
 
-    &:hover {
+    &:hover,
+    &.flat:hover {
       @include button(hover);
       -gtk-icon-filter: brightness(1.2);
     }
diff --git a/gtk/theme/HighContrast/gtk-contained-inverse.css 
b/gtk/theme/HighContrast/gtk-contained-inverse.css
index ddafbf9..d1a3a4e 100644
--- a/gtk/theme/HighContrast/gtk-contained-inverse.css
+++ b/gtk/theme/HighContrast/gtk-contained-inverse.css
@@ -178,7 +178,7 @@ button.sidebar-button:hover:active, button.titlebutton:hover:active, button.flat
 
 button.sidebar-button:backdrop, button.titlebutton:backdrop, button.sidebar-button:disabled, 
button.titlebutton:disabled, button.sidebar-button:backdrop:disabled, button.titlebutton:backdrop:disabled, 
button.flat:backdrop, button.flat:disabled, button.flat:backdrop:disabled { border-width: 2px; border-style: 
solid; color: gray; background-color: transparent; background-image: none; border-color: transparent; }
 
-button.titlebutton:hover, button:hover { border-width: 2px; border-style: solid; color: #fff; 
background-color: #000; border-color: gray; background-image: none; -gtk-icon-filter: brightness(1.2); }
+button.titlebutton:hover, button.sidebar-button:hover, button.titlebutton:hover, button:hover, 
button.flat:hover { border-width: 2px; border-style: solid; color: #fff; background-color: #000; 
border-color: gray; background-image: none; -gtk-icon-filter: brightness(1.2); }
 
 button.titlebutton:active, button.titlebutton:checked, button:active, button:checked { border-width: 2px; 
border-style: solid; background-image: none; color: black; background-color: white; border-color: gray; 
transition-duration: 50ms; }
 
diff --git a/gtk/theme/HighContrast/gtk-contained.css b/gtk/theme/HighContrast/gtk-contained.css
index 4991ca9..fae7eec 100644
--- a/gtk/theme/HighContrast/gtk-contained.css
+++ b/gtk/theme/HighContrast/gtk-contained.css
@@ -178,7 +178,7 @@ button.sidebar-button:hover:active, button.titlebutton:hover:active, button.flat
 
 button.sidebar-button:backdrop, button.titlebutton:backdrop, button.sidebar-button:disabled, 
button.titlebutton:disabled, button.sidebar-button:backdrop:disabled, button.titlebutton:backdrop:disabled, 
button.flat:backdrop, button.flat:disabled, button.flat:backdrop:disabled { border-width: 2px; border-style: 
solid; color: gray; background-color: transparent; background-image: none; border-color: transparent; }
 
-button.titlebutton:hover, button:hover { border-width: 2px; border-style: solid; color: #000; 
background-color: #fff; border-color: gray; background-image: none; -gtk-icon-filter: brightness(1.2); }
+button.titlebutton:hover, button.sidebar-button:hover, button.titlebutton:hover, button:hover, 
button.flat:hover { border-width: 2px; border-style: solid; color: #000; background-color: #fff; 
border-color: gray; background-image: none; -gtk-icon-filter: brightness(1.2); }
 
 button.titlebutton:active, button.titlebutton:checked, button:active, button:checked { border-width: 2px; 
border-style: solid; background-image: none; color: white; background-color: black; border-color: gray; 
transition-duration: 50ms; }