diff --git a/dotfiles/.config/mpv/mpv.conf b/dotfiles/.config/mpv/mpv.conf
index 1b8442f..e9ce4c8 100644
--- a/dotfiles/.config/mpv/mpv.conf
+++ b/dotfiles/.config/mpv/mpv.conf
@@ -81,3 +81,8 @@ border=no
 osd-bar=no
 osd-bold=yes
 osd-font-size=36
+
+### Fix window size under Niri ###
+keepaspect=no
+geometry=
+autofit-larger=100%
\ No newline at end of file
diff --git a/dotfiles/.config/niri/config.kdl b/dotfiles/.config/niri/config.kdl
new file mode 100644
index 0000000..9807c27
--- /dev/null
+++ b/dotfiles/.config/niri/config.kdl
@@ -0,0 +1,298 @@
+animations {
+    // Uncomment to turn off all animations.
+    // You can also put "off" into each individual animation to disable it.
+    // off
+
+    // Slow down all animations by this factor. Values below 1 speed them up instead.
+    // slowdown 3.0
+
+    // Individual animations.
+
+    workspace-switch {
+        spring damping-ratio=1.0 stiffness=1000 epsilon=0.0001
+    }
+
+    window-open {
+        duration-ms 150
+        curve "ease-out-expo"
+    }
+
+    window-close {
+        duration-ms 150
+        curve "ease-out-quad"
+    }
+
+    horizontal-view-movement {
+        spring damping-ratio=1.0 stiffness=800 epsilon=0.0001
+    }
+
+    window-movement {
+        spring damping-ratio=1.0 stiffness=800 epsilon=0.0001
+    }
+
+    window-resize {
+        spring damping-ratio=1.0 stiffness=800 epsilon=0.0001
+    }
+
+    config-notification-open-close {
+        spring damping-ratio=0.6 stiffness=1000 epsilon=0.001
+    }
+
+    screenshot-ui-open {
+        duration-ms 200
+        curve "ease-out-quad"
+    }
+}
+
+
+binds {
+    // App Launcher
+    Super+Space { spawn "fuzzel"; }
+
+    // Shortcuts
+    Super+Shift+Slash { show-hotkey-overlay; }
+    Super+E { spawn "nemo"; }
+    Super+B { spawn "floorp";}
+    Super+L { spawn "hyprlock";}
+    Super+M { spawn-sh "$HOME/.config/niri/switch_monitors.sh"; }
+    Ctrl+Super+Q { spawn "wlogout"; }
+    Super+Return { spawn "alacritty"; }
+    Super+S { screenshot; }
+    Super+Ctrl+S { screenshot-window; }
+    Super+Ctrl+Alt+Print { screenshot-screen; }
+
+    // Window actions
+    Super+F { fullscreen-window; }
+    Super+Q { close-window; }
+
+    // Workspace jumping
+    Super+1 { focus-workspace 1; }
+    Super+2 { focus-workspace 2; }
+    Super+3 { focus-workspace 3; }
+    Super+4 { focus-workspace 4; }
+    Super+5 { focus-workspace 5; }
+    Super+6 { focus-workspace 6; }
+    Super+7 { focus-workspace 7; }
+    Super+8 { focus-workspace 8; }
+    Super+9 { focus-workspace 9; }
+    Super+0 { focus-workspace 10; }
+
+    // Window movement between Workspace
+    Super+Shift+1 { move-window-to-workspace 1; }
+    Super+Shift+2 { move-window-to-workspace 2; }
+    Super+Shift+3 { move-window-to-workspace 3; }
+    Super+Shift+4 { move-window-to-workspace 4; }
+    Super+Shift+5 { move-window-to-workspace 5; }
+    Super+Shift+6 { move-window-to-workspace 6; }
+    Super+Shift+7 { move-window-to-workspace 7; }
+    Super+Shift+8 { move-window-to-workspace 8; }
+    Super+Shift+9 { move-window-to-workspace 9; }
+    Super+Shift+0 { move-window-to-workspace 10; }
+
+    // Window focus movement
+    /// Using familier keys
+    Alt+Tab { focus-column-right; }
+    Alt+Shift+Tab  { focus-column-left; }
+
+    /// Using Arrow keys
+    Super+Left  { focus-column-left; }
+    Super+Down  { focus-window-down; }
+    Super+Up    { focus-window-up; }
+    Super+Right { focus-column-right; }
+
+    /// Using Vim-like keys
+    Super+Shift+H { focus-column-left; }
+    Super+Shift+J { focus-window-down; }
+    Super+Shift+K { focus-window-up; }
+    Super+Shift+L { focus-column-right; }
+
+    // Window direction movement
+    /// Using Arrow keys
+    Super+Shift+Left  { move-column-left; }
+    Super+Shift+Down  { move-window-down; }
+    Super+Shift+Up    { move-window-up; }
+    Super+Shift+Right { move-column-right; }
+
+    Super+Home { focus-column-first; }
+    Super+End  { focus-column-last; }
+    Super+Ctrl+Home { move-column-to-first; }
+    Super+Ctrl+End  { move-column-to-last; }
+
+    Super+Shift+Alt+Left  { focus-monitor-left; }
+    Super+Shift+Alt+Down  { focus-monitor-down; }
+    Super+Shift+Alt+Up    { focus-monitor-up; }
+    Super+Shift+Alt+Right { focus-monitor-right; }
+
+    Super+Shift+Ctrl+Left  { move-column-to-monitor-left; }
+    Super+Shift+Ctrl+Down  { move-column-to-monitor-down; }
+    Super+Shift+Ctrl+Up    { move-column-to-monitor-up; }
+    Super+Shift+Ctrl+Right { move-column-to-monitor-right; }
+
+    Super+Page_Down      { focus-workspace-down; }
+    Super+Page_Up        { focus-workspace-up; }
+    Super+U              { focus-workspace-down; }
+    Super+I              { focus-workspace-up; }
+    Super+Ctrl+Page_Down { move-column-to-workspace-down; }
+    Super+Ctrl+Page_Up   { move-column-to-workspace-up; }
+    Super+Ctrl+U         { move-column-to-workspace-down; }
+    Super+Ctrl+I         { move-column-to-workspace-up; }
+
+    Super+Shift+Page_Down { move-workspace-down; }
+    Super+Shift+Page_Up   { move-workspace-up; }
+    Super+Shift+U         { move-workspace-down; }
+    Super+Shift+I         { move-workspace-up; }
+
+    Super+WheelScrollDown      cooldown-ms=150 { focus-workspace-down; }
+    Super+WheelScrollUp        cooldown-ms=150 { focus-workspace-up; }
+    Super+Ctrl+WheelScrollDown cooldown-ms=150 { move-column-to-workspace-down; }
+    Super+Ctrl+WheelScrollUp   cooldown-ms=150 { move-column-to-workspace-up; }
+
+    Super+WheelScrollRight      { focus-column-right; }
+    Super+WheelScrollLeft       { focus-column-left; }
+    Super+Ctrl+WheelScrollRight { move-column-right; }
+    Super+Ctrl+WheelScrollLeft  { move-column-left; }
+
+    Super+Shift+WheelScrollDown      { focus-column-right; }
+    Super+Shift+WheelScrollUp        { focus-column-left; }
+    Super+Ctrl+Shift+WheelScrollDown { move-column-right; }
+    Super+Ctrl+Shift+WheelScrollUp   { move-column-left; }
+
+    // Alternatively, there are commands to move just a single window:
+    // Super+Ctrl+1 { move-window-to-workspace 1; }
+
+    // Switches focus between the current and the previous workspace.
+    // Super+Tab { focus-workspace-previous; }
+
+    Super+Comma  { consume-window-into-column; }
+    Super+Period { expel-window-from-column; }
+
+    Super+R { switch-preset-column-width; }
+    Super+Shift+R { reset-window-height; }
+    Super+Shift+F { maximize-column; }
+
+    Super+C { center-column; }
+
+    Super+Minus { set-column-width "-10%"; }
+    Super+Equal { set-column-width "+10%"; }
+
+    // Finer height adjustments when in column with other windows.
+    Super+Shift+Minus { set-window-height "-10%"; }
+    Super+Shift+Equal { set-window-height "+10%"; }
+
+    // Actions to switch layouts.
+    // Note: if you uncomment these, make sure you do NOT have
+    // a matching layout switch hotkey configured in xkb options above.
+    // Having both at once on the same hotkey will break the switching,
+    // since it will switch twice upon pressing the hotkey (once by xkb, once by niri).
+    // Super+Space       { switch-layout "next"; }
+    // Super+Shift+Space { switch-layout "prev"; }
+
+    // The quit action will show a confirmation dialog to avoid accidental exits.
+    Super+Shift+E { quit; }
+
+    // Powers off the monitors. To turn them back on, do any input like
+    // moving the mouse or pressing any other key.
+    Super+Shift+P { power-off-monitors; }
+
+    // Volume control
+    XF86AudioLowerVolume allow-when-locked=true { spawn "swayosd-client" "--output-volume" "-2"; }
+    XF86AudioMute allow-when-locked=true { spawn "swayosd-client" "--output-volume" "mute-toggle"; }
+    XF86AudioRaiseVolume allow-when-locked=true { spawn "swayosd-client" "--output-volume" "+2"; }
+    XF86MonBrightnessDown allow-when-locked=true { spawn "swayosd-client" "--brightness" "-5"; }
+    XF86MonBrightnessUp allow-when-locked=true { spawn "swayosd-client" "--brightness" "+5"; }
+
+    // Volume control (bonus)
+    Ctrl+Alt+Down allow-when-locked=true { spawn "swayosd-client" "--output-volume" "-2"; }
+    Ctrl+Alt+Up allow-when-locked=true { spawn "swayosd-client" "--output-volume" "+2"; }
+}
+
+
+environment {
+    CURRENT_COMPOSITOR "niri"
+    DISPLAY ":0"
+    XDG_CURRENT_DESKTOP "niri"
+    XDG_SESSION_DESKTOP "niri"
+}
+
+
+hotkey-overlay {
+    skip-at-startup
+}
+
+
+input {
+    disable-power-key-handling
+    focus-follows-mouse
+    warp-mouse-to-focus
+
+    mouse {
+        accel-profile "flat"
+        scroll-factor 0.5
+    }
+    touchpad {
+        accel-profile "flat"
+        dwt
+        natural-scroll
+        scroll-factor 0.5
+        tap
+    }
+}
+
+
+prefer-no-csd
+
+
+screenshot-path "~/Pictures/Screenshots/SCREENSHOT-%Y-%m-%d-%H:%M:%S.png"
+
+
+spawn-at-startup "fcitx5" "-d" "-r"
+spawn-at-startup "nm-applet"
+spawn-at-startup "sh" "-c" "dbus-update-activation-environment --systemd --all && systemctl --user stop niri-session.target && systemctl --user start niri-session.target"
+spawn-at-startup "swayosd-server"
+spawn-at-startup "swww-daemon"
+spawn-at-startup "sh" "-c" "sleep 1 && swww img $HOME/Git/DCGOS/dotfiles/.local/share/wallpapers/yohoho.jpg"
+spawn-at-startup "swww" "restore"
+spawn-at-startup "waybar"
+
+window-rule {
+    block-out-from "screen-capture"
+
+    match app-id=r#"^org\.keepassxc\.KeePassXC$"#
+    match app-id=r#"^org\.gnome\.World\.Secrets$"#
+
+    // Use this instead if you want them visible on third-party screenshot tools.
+    // block-out-from "screencast"
+}
+window-rule {
+    clip-to-geometry true
+    geometry-corner-radius 10
+}
+
+layout {
+    center-focused-column "on-overflow"
+    border {
+        width 1
+        active-color "#313244FF"
+        inactive-color "#1e1e2eFF"
+    }
+    default-column-width { proportion 1.00; }
+    focus-ring {
+        off
+        active-color "#31324400"
+        inactive-color "#31324400"
+        width 3
+    }
+    gaps 2
+    preset-column-widths {
+        proportion 0.33333
+        proportion 0.5
+        proportion 0.66667
+    }
+
+    struts {
+        left 0.1
+        right 0.1
+        top 0
+        bottom 0
+    }
+}
\ No newline at end of file
diff --git a/dotfiles/.config/niri/switch_monitors.sh b/dotfiles/.config/niri/switch_monitors.sh
new file mode 100755
index 0000000..2c02d6b
--- /dev/null
+++ b/dotfiles/.config/niri/switch_monitors.sh
@@ -0,0 +1,50 @@
+#!/usr/bin/env bash
+# ~/.config/niri/switch_monitors.sh
+# 切换 Niri 下显示模式：内屏 → 外屏 → 扩展
+
+STATE_FILE="/tmp/niri_monitor_mode"
+INTERNAL="eDP-1"
+EXTERNAL="DP-1"
+
+MODES=("internal_only" "external_only" "extended")
+
+# 读取上次模式
+if [[ -f "$STATE_FILE" ]]; then
+  LAST_MODE=$(cat "$STATE_FILE")
+else
+  LAST_MODE="extended"
+fi
+
+# 下一个模式
+NEXT_INDEX=0
+for i in "${!MODES[@]}"; do
+  if [[ "${MODES[$i]}" == "$LAST_MODE" ]]; then
+    NEXT_INDEX=$(((i + 1) % ${#MODES[@]}))
+    break
+  fi
+done
+NEXT_MODE="${MODES[$NEXT_INDEX]}"
+
+# 应用模式
+case "$NEXT_MODE" in
+internal_only)
+  wlr-randr --output "$EXTERNAL" --off
+  wlr-randr --output "$INTERNAL" --on --mode 2560x1600 --pos 0,0 --scale 1.25
+  notify-send "显示模式" "仅内屏"
+  ;;
+external_only)
+  wlr-randr --output "$EXTERNAL" --on --mode 2560x1440@144 --pos 0,0 --scale 1.25
+  wlr-randr --output "$INTERNAL" --off
+  notify-send "显示模式" "仅外屏"
+  ;;
+extended)
+  wlr-randr --output "$INTERNAL" --on
+  notify-send "显示模式" "扩展模式"
+  ;;
+esac
+
+echo "$NEXT_MODE" > "$STATE_FILE"
+
+# 刷新 Niri 布局（防止残影）
+sleep 0.5
+niri msg reload-layout >/dev/null 2>&1 || true
diff --git a/home/wayland/niri.nix b/home/wayland/niri.nix
new file mode 100644
index 0000000..34827a4
--- /dev/null
+++ b/home/wayland/niri.nix
@@ -0,0 +1,51 @@
+{
+  hostname,
+  lib,
+  pkgs,
+  ...
+}: let
+  inherit (import ../../hosts/${hostname}/env.nix) WM;
+in
+  with lib;
+    mkIf (WM == "niri") {
+      systemd.user.targets.niri-session = {
+        Unit = {
+          Description = "niri compositor session";
+          Documentation = "man:systemd.special(7)";
+        };
+        Target = {
+          After = "graphical-session-pre.target";
+          BindsTo = "graphical-session.target";
+          Wants = "graphical-session-pre.target";
+          DefaultDependencies = false;
+        };
+      };
+      systemd.user.services.xdg-desktop-portal-gnome = {
+        Unit = {
+          Description = "Portal service (GNOME implementation)";
+        };
+        Service = {
+          Type = "dbus";
+          BusName = "org.freedesktop.impl.portal.desktop.gnome";
+          ExecStart = "${pkgs.xdg-desktop-portal-gnome}/libexec/xdg-desktop-portal-gnome";
+        };
+      };
+      home.packages = with pkgs; [
+        niri
+        xwayland-satellite
+      ];
+      xdg.portal = {
+        config = {
+          common = {
+            default = [
+              "gnome"
+              "gtk"
+            ];
+          };
+        };
+        extraPortals = [
+          pkgs.xdg-desktop-portal-gtk
+          pkgs.xdg-desktop-portal-gnome
+        ];
+      };
+    }
diff --git a/hosts/dos/env.nix b/hosts/dos/env.nix
index 50172f7..5f0f17f 100644
--- a/hosts/dos/env.nix
+++ b/hosts/dos/env.nix
@@ -54,6 +54,6 @@
   ### For Hyprland see https://wiki.hyprland.org/Configuring/XWayland/#hidpi-xwayland
   ### For sway see https://github.com/swaywm/sway/wiki#hidpi
 
-  WM = "Hyprland";
+  WM = "niri";
   ### Possible options: Hyprland ; niri ; sway
 }
diff --git a/modules/system/environment.nix b/modules/system/environment.nix
index 21a2c37..11543af 100644
--- a/modules/system/environment.nix
+++ b/modules/system/environment.nix
@@ -69,6 +69,9 @@ in {
       libvirt
       lm_sensors
 
+      # Niri
+      wlr-randr
+
       # Dev
       go
       gcc