diff --git a/colors.lua b/colors.lua
index 9e04d02..a8418d0 100644
--- a/colors.lua
+++ b/colors.lua
@@ -5,7 +5,6 @@ local math = math
 local floor = math.floor
 local max = math.max
 local min = math.min
-local pow = math.pow
 local random = math.random
 local gcolor = require("gears.color")
 local parse_color = gcolor.parse_color
@@ -88,8 +87,7 @@ end
 local function relative_luminance(color)
     local r, g, b = hex2rgb(color)
     local function from_sRGB(u)
-        return u <= 0.0031308 and 25 * u / 323 or
-                   pow(((200 * u + 11) / 211), 12 / 5)
+        return u <= 0.0031308 and 25 * u / 323 or ((200 * u + 11) / 211) ^ (12 / 5)
     end
     return 0.2126 * from_sRGB(r) + 0.7152 * from_sRGB(g) + 0.0722 * from_sRGB(b)
 end
diff --git a/init.lua b/init.lua
index e0ac651..7f5745c 100644
--- a/init.lua
+++ b/init.lua
@@ -54,7 +54,7 @@ local ipairs = ipairs
 -- ============================================================
 local lgi = require("lgi")
 local cairo = lgi.cairo
-local gdk = lgi.Gdk
+local gdk = lgi.require('Gdk', '3.0')
 local get_default_root_window = gdk.get_default_root_window
 local pixbuf_get_from_surface = gdk.pixbuf_get_from_surface
 local pixbuf_get_from_window = gdk.pixbuf_get_from_window