Add focus child using disabled stacking shortcut, try with borders

.config/sway/config

@@ -131,6 +131,7 @@ bindsym $mod+Mod1+$down move workspace to output down
 
     # Move focus to the parent container
     bindsym $mod+a focus parent
+    bindsym $mod+s focus child
 #
 # Scratchpad:
 #
@@ -248,7 +249,7 @@ smart_gaps on
 # Titlebars
 #
 font pango:monospace 12px
-default_border pixel 2
+#default_border pixel 2
 titlebar_border_thickness 2
 hide_edge_borders smart
 #
@@ -312,6 +313,5 @@ exec_always {
 
 #
 # App Specific Styling
-for_window [app_id="termite"] border pixel
+#for_window [app_id="termite"] border pixel
 for_window [app_id=pavucontrol] floating enable
-for_window [app_id=".*"] border pixel 4