[gnome-shell-sass] theme: Fix off-centered clickable area of dash items

[Florian Müllner <fmuellner src gnome org>]

commit 936ad30872466600d786f2197641bc4cc1a36f5a
Author: nana-4 <hnmaigo gmail com>
Date:   Mon Jan 13 13:58:20 2020 +0900

    theme: Fix off-centered clickable area of dash items
    
    https://gitlab.gnome.org/GNOME/gnome-shell/issues/2088

 widgets/_dash.scss | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)
---
diff --git a/widgets/_dash.scss b/widgets/_dash.scss
index 20cdae5..5c1b4e1 100644
--- a/widgets/_dash.scss
+++ b/widgets/_dash.scss
@@ -1,13 +1,13 @@
 /* Dash */
 
 $dash_placeholder_size: 32px;
+$dash_spacing: $base_padding + 4px;
 $dash_border_radius: $modal_radius * 1.5;
 
 #dash {
   @extend %overview_panel;
   @include fontsize($base_font_size - 2);
-  padding: 0;
-  padding-bottom: $base_padding + 4px;
+  padding: ($dash_spacing / 2) 0;
 
   //fixme: can't have non uniform borders :(
   border-radius: 0 $dash_border_radius $dash_border_radius 0; 
@@ -32,8 +32,7 @@ $dash_border_radius: $modal_radius * 1.5;
 
 // Dash Items
 .dash-item-container > StWidget {
-  padding: $base_padding + 4px;
-  padding-bottom: 0;
+  padding: ($dash_spacing / 2) $dash_spacing;
 }
 
 // OSD Tooltip