[gnome-shell] theme: Adjust workspaces thumbnails visuals

[Marge Bot <marge-bot src gnome org>]

commit 6e13dbac11aa6a8b43b59b1bd21db004de8ae551
Author: Georges Basile Stavracas Neto <georges stavracas gmail com>
Date:   Mon Jan 25 21:11:28 2021 -0300

    theme: Adjust workspaces thumbnails visuals
    
    Remove the borders, and make each thumbnail have a background color
    that matches other elements like the Dash.
    
    Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/1593>

 .../gnome-shell-sass/widgets/_workspace-thumbnails.scss      | 12 ++++--------
 1 file changed, 4 insertions(+), 8 deletions(-)
---
diff --git a/data/theme/gnome-shell-sass/widgets/_workspace-thumbnails.scss 
b/data/theme/gnome-shell-sass/widgets/_workspace-thumbnails.scss
index da76381535..774408bb7c 100644
--- a/data/theme/gnome-shell-sass/widgets/_workspace-thumbnails.scss
+++ b/data/theme/gnome-shell-sass/widgets/_workspace-thumbnails.scss
@@ -2,24 +2,20 @@
 
 // thumbnails in overview
 .workspace-thumbnails {
-  @extend %overview_panel;
   visible-width: 32px; //amount visible before hover
   spacing: $base_spacing;
   padding: $base_padding;
 
-  border-radius: $modal_radius 0 0 $modal_radius;
-  border-right-width: 0;
-
-  &:rtl {
-    border-radius: 0 $modal_radius $modal_radius 0;
-    border-left-width: 0;
+  .workspace-thumbnail {
+    @extend %overview_panel;
+    border-radius: 3px;
   }
 
   // drag and drop indicator
   .placeholder {
     background-image: url("resource:///org/gnome/shell/theme/dash-placeholder.svg");
     background-size: contain;
-    height: 24px;
+    width: 18px;
   }
 }