Fix: Only set NVIDIA env vars when the NVIDIA driver is loaded, drop duplicate Qt theme var

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

dotfiles/.config/hypr/core/env.lua

@@ -19,8 +19,7 @@ hl.env("XDG_SESSION_TYPE", "wayland")
 -- QT Variables
 hl.env("QT_AUTO_SCREEN_SCALE_FACTOR", "1")
 hl.env("QT_WAYLAND_DISABLE_WINDOWDECORATION", "1")
-hl.env("QT_QPA_PLATFORMTHEME", "qt5ct")
-hl.env("QT_QPA_PLATFORMTHEME", "qt6ct")
+hl.env("QT_QPA_PLATFORMTHEME", "qt6ct") -- qt6ct also styles Qt5 apps that read it; qt5ct.conf is kept in sync
 
 -- hyprland-qt-support
 hl.env("QT_QUICK_CONTROLS_STYLE", "org.hyprland.style")
@@ -49,13 +48,17 @@ hl.env("MOZ_ENABLE_WAYLAND", "1")
 hl.env("ELECTRON_OZONE_PLATFORM_HINT", "auto") -- auto selects Wayland if possible, X11 otherwise
 
 -- NVIDIA
--- This is from the Hyprland wiki. Uncomment below if an nvidia GPU is detected.
 -- See hyprland wiki https://wiki.hyprland.org/Nvidia/#environment-variables
-
-hl.env("LIBVA_DRIVER_NAME", "nvidia")
-hl.env("__GLX_VENDOR_LIBRARY_NAME", "nvidia")
-hl.env("NVD_BACKEND", "direct")
-hl.env("GSK_RENDERER", "ngl")
+-- Only when the NVIDIA kernel driver is loaded, so the same config works on the
+-- laptop (forcing LIBVA_DRIVER_NAME=nvidia there breaks VA-API video decoding).
+local nvidia = io.open("/proc/driver/nvidia/version")
+if nvidia then
+    nvidia:close()
+    hl.env("LIBVA_DRIVER_NAME", "nvidia")
+    hl.env("__GLX_VENDOR_LIBRARY_NAME", "nvidia")
+    hl.env("NVD_BACKEND", "direct")
+    hl.env("GSK_RENDERER", "ngl")
+end
 
 -- additional ENV's for nvidia. Caution, activate with care
 -- hl.env("GBM_BACKEND", "nvidia-drm")