diff --git a/hypr/.config/hypr/hypridle.conf b/hypr/.config/hypr/hypridle.conf
index 28182d7..ac6fd3a 100644
--- a/hypr/.config/hypr/hypridle.conf
+++ b/hypr/.config/hypr/hypridle.conf
@@ -1,14 +1,28 @@
-# hypridle.conf — idle stages: screensaver (300s, backend in modules/screensaver.lua) -> Noctalia lock (10min) -> DPMS off.
+# hypridle.conf — screensaver only.
 # Managed by dotfiles (stow hypr).
 #
-# NOTE: this Hyprland (hyprmod Lua runtime, 0.56.x) evaluates `hyprctl dispatch`
-# args as Lua — classic `dispatch dpms off` syntax fails. Dispatchers must be
-# hl.dsp.* expressions (e.g. hl.dsp.dpms(false)).
+# IDLE OWNERSHIP: Noctalia owns dim / lock / screen-off / suspend via its own
+# [idle] block in ~/.config/noctalia/config.toml. hypridle is started only for
+# the Noctalia shell (see hyprland.lua) and contributes just the tte
+# screensaver. Do not re-add lock/DPMS listeners here — that duplication is
+# what made two idle managers fight over the same transitions.
+#
+# lock_cmd goes through scripts/lock.sh, which resolves the active shell from
+# env.lua. That keeps a manually started hypridle under Caelestia from calling
+# `noctalia ...` (which would silently do nothing).
+#
+# WARNING — do not add DPMS dispatchers back to this file. This Hyprland
+# (hyprmod Lua runtime, 0.56.x) evaluates `hyprctl dispatch` args as Lua, and
+# the dpms dispatcher takes a TABLE, not a boolean:
+#     WRONG (silently becomes a TOGGLE, ignoring the argument):
+#         hyprctl dispatch 'hl.dsp.dpms(true)'
+#     RIGHT:
+#         hyprctl dispatch 'hl.dsp.dpms({action="enable"})'
+# A toggle in after_sleep_cmd turns the display OFF on resume, and with
+# misc:key_press_enables_dpms = false nothing could wake it again.
 
 general {
-    lock_cmd = pidof -q noctalia || noctalia msg session lock
-    before_sleep_cmd = loginctl lock-session
-    after_sleep_cmd = hyprctl dispatch 'hl.dsp.dpms(true)'
+    lock_cmd = ~/.config/hypr/scripts/lock.sh
 }
 
 # Screensaver via backend wrappers (switch backend in modules/screensaver.lua).
@@ -17,16 +31,3 @@ listener {
     on-timeout = ~/.config/hypr/scripts/screensaver-start.sh
     on-resume = ~/.config/hypr/scripts/screensaver-stop.sh
 }
-
-# 10min: lock via Noctalia (SUPER+L runs the same command).
-listener {
-    timeout = 600
-    on-timeout = loginctl lock-session
-}
-
-# 10m30s: power off displays.
-listener {
-    timeout = 630
-    on-timeout = hyprctl dispatch 'hl.dsp.dpms(false)'
-    on-resume = hyprctl dispatch 'hl.dsp.dpms(true)'
-}
diff --git a/hypr/.config/hypr/hyprland.lua b/hypr/.config/hypr/hyprland.lua
index a15e0eb..b4795fa 100644
--- a/hypr/.config/hypr/hyprland.lua
+++ b/hypr/.config/hypr/hyprland.lua
@@ -62,5 +62,8 @@ if fid_gui then
     require("hyprland-buntes-monster-gui")
 end
 
--- For Noctalia Color templates
-require("noctalia").apply_theme()
+-- For Noctalia Color templates. Noctalia-only: under Caelestia this would
+-- otherwise push Noctalia's Catppuccin border colors into the compositor.
+if env.shell == "noctalia" then
+    require("noctalia").apply_theme()
+end
diff --git a/hypr/.config/hypr/modules/lock.lua b/hypr/.config/hypr/modules/lock.lua
new file mode 100644
index 0000000..f9c4891
--- /dev/null
+++ b/hypr/.config/hypr/modules/lock.lua
@@ -0,0 +1,33 @@
+-- Single source of truth for "how do I lock this session", keyed on the
+-- active shell in env.lua. Consumed by two callers:
+--   * scripts/lock.sh (hypridle's lock_cmd) - loaded via plain dofile
+--   * modules/shell_commands.lua (SUPER+L) - loaded via require
+--
+-- Both contexts load this file, so it must NOT use require("env"): Lua's
+-- default package.path is cwd-relative, and that only resolves inside
+-- ~/.config/hypr. hypridle's cwd is not guaranteed. Resolve by path instead.
+local config_home = os.getenv("XDG_CONFIG_HOME") or os.getenv("HOME") .. "/.config"
+local prefix = config_home .. "/hypr/"
+
+local function load_env()
+    local fid = io.open(prefix .. "env.lua")
+    if fid then
+        fid:close()
+        return dofile(prefix .. "env.lua")
+    end
+    return dofile(prefix .. "env_example.lua")
+end
+
+local LOCK = {
+    noctalia = "noctalia msg session lock",
+    caelestia = "caelestia shell lock lock",
+}
+
+local env = load_env()
+
+return {
+    shell = env.shell,
+    -- nil for an unknown shell; scripts/lock.sh treats that as a hard error
+    -- rather than reporting success while nothing is actually locked.
+    cmd = LOCK[env.shell],
+}
diff --git a/hypr/.config/hypr/modules/look_and_feel.lua b/hypr/.config/hypr/modules/look_and_feel.lua
index de1cae6..60918fa 100644
--- a/hypr/.config/hypr/modules/look_and_feel.lua
+++ b/hypr/.config/hypr/modules/look_and_feel.lua
@@ -253,5 +253,8 @@ hl.config({
 	misc = {
 		force_default_wallpaper = -1,
 		disable_hyprland_logo = false,
+		-- Both *_enables_dpms default to false, so a display left in DPMS-off
+		-- is unrecoverable without a TTY switch. A keypress should wake it.
+		key_press_enables_dpms = true,
 	},
 })
diff --git a/hypr/.config/hypr/modules/shell_commands.lua b/hypr/.config/hypr/modules/shell_commands.lua
index 173e803..57c4174 100644
--- a/hypr/.config/hypr/modules/shell_commands.lua
+++ b/hypr/.config/hypr/modules/shell_commands.lua
@@ -1,6 +1,10 @@
 
 local env = require("env")
 
+-- Shell-agnostic on purpose: the active shell is resolved inside lock.sh from
+-- env.lua, so hypridle's lock_cmd and this bind cannot drift apart.
+local LOCK = "~/.config/hypr/scripts/lock.sh"
+
 local commands = {
     session = "",
     logout = "",
@@ -9,7 +13,7 @@ local commands = {
     menu = "",
     settings = "",
     control_center = "",
-    lock = "",
+    lock = LOCK,
     screensaver = "sh ~/.config/hypr/scripts/screensaver-start.sh force",
     wallpaper_select = "",
     keybinds_show = "sh ~/.config/hypr/scripts/show-keybinds.sh",
@@ -28,7 +32,6 @@ if env.shell == "noctalia" then
     commands.menu = "noctalia msg panel-toggle launcher"
     commands.settings = "noctalia msg settings-toggle"
     commands.control_center = "noctalia msg panel-toggle control-center"
-    commands.lock = "noctalia msg session lock"
     commands.wallpaper_select = "noctalia msg panel-toggle wallpaper"
 elseif env.shell == "caelestia" then
     commands.session = "caelestia shell drawers toggle session"
@@ -38,7 +41,6 @@ elseif env.shell == "caelestia" then
     commands.menu = "caelestia shell drawers toggle launcher"
     commands.settings = "caelestia shell drawers toggle dashboard"
     commands.control_center = "caelestia shell drawers toggle sidebar"
-    commands.lock = "caelestia shell lock lock"
     commands.wallpaper_select = "caelestia shell drawers toggle launcher && sleep 0.1 && wtype \">wallpaper \""
     commands.clipboard = "caelestia clipboard"
     commands.clipboard_delete = "caelestia clipboard -d"
diff --git a/hypr/.config/hypr/scripts/lock.sh b/hypr/.config/hypr/scripts/lock.sh
new file mode 100755
index 0000000..ba9c405
--- /dev/null
+++ b/hypr/.config/hypr/scripts/lock.sh
@@ -0,0 +1,30 @@
+#!/usr/bin/env bash
+# lock.sh — lock the session with the active shell's own lock command.
+# The mapping lives in modules/lock.lua (reads env.lua), so neither hypridle's
+# lock_cmd nor the SUPER+L bind hardcodes a shell. This is what keeps a
+# manually started hypridle under Caelestia from failing on `noctalia ...`.
+#
+# Usage: lock.sh   (no args; safe to call while locked)
+
+set -euo pipefail
+
+# Resolve from this script's own location so it works through the
+# ~/.config/hypr symlink and does not depend on XDG_CONFIG_HOME.
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+LOCK_LUA="$(cd "$SCRIPT_DIR/.." && pwd)/modules/lock.lua"
+
+CMD="$(LOCK_LUA="$LOCK_LUA" lua -e 'print(dofile(os.getenv("LOCK_LUA")).cmd)' 2>/dev/null)" || {
+    echo "lock: cannot read modules/lock.lua" >&2
+    exit 1
+}
+
+# Empty here means env.lua named a shell with no known lock command. Fail loudly
+# instead of exiting 0, or a caller would think the session got locked.
+[[ -n "$CMD" ]] || {
+    echo "lock: no lock command for the active shell (check env.lua)" >&2
+    exit 1
+}
+
+# Word-split on purpose: CMD is a command line, not a single path.
+# shellcheck disable=SC2086
+exec $CMD
diff --git a/hypr/.config/noctalia/config.toml b/hypr/.config/noctalia/config.toml
index 823b062..140d051 100644
--- a/hypr/.config/noctalia/config.toml
+++ b/hypr/.config/noctalia/config.toml
@@ -50,8 +50,10 @@ resume_command = "brightnessctl -r"
 [idle.behavior.kbd-off]
 timeout = 300
 action = "command"
-command = "brightnessctl -sd rgb:kbd_backlight set 0"
-resume_command = "brightnessctl -rd rgb:kbd_backlight"
+# This ThinkPad exposes the keyboard backlight as tpacpi::kbd_backlight;
+# the previous rgb:kbd_backlight matched no device and errored out silently.
+command = "brightnessctl -sd tpacpi::kbd_backlight set 0"
+resume_command = "brightnessctl -rd tpacpi::kbd_backlight"
 
 [idle.behavior.lock]
 timeout = 900