No border when single window

rc.lua

@@ -10,6 +10,7 @@ require("awful.autofocus")
 local wibox = require("wibox")
 -- Theme handling library
 local beautiful = require("beautiful")
+beautiful.gap_single_client   = false
 -- Notification library
 local naughty = require("naughty")
 local menubar = require("menubar")
@@ -259,7 +260,7 @@ awful.screen.connect_for_each_screen(function(s)
 
     -- Create the wibox
     local wibar_width = s.geometry.width / 4
-    local wibar_height = 20
+    local wibar_height = 15
     s.mywibox = wibox({
         x = s.geometry.width - wibar_width,
         y = s.geometry.height - wibar_height,
@@ -791,7 +792,19 @@ end)
 client.connect_signal("focus", function(c) c.border_color = beautiful.border_focus end)
 client.connect_signal("unfocus", function(c) c.border_color = beautiful.border_normal end)
 
-awful.screen.set_auto_dpi_enabled(true)
+-- No borders when rearranging only 1 non-floating or maximized client
+screen.connect_signal("arrange", function (s)
+    local only_one = #s.tiled_clients == 1
+    for _, c in pairs(s.clients) do
+        if only_one and not c.floating or c.maximized then
+            c.border_width = 0
+        else
+            c.border_width = beautiful.border_width -- your border width
+        end
+    end
+end)
+
+-- awful.screen.set_auto_dpi_enabled(true)
 
 -- load the widget code