diff --git a/Dockerfile b/Dockerfile
index 201e69d..32afa77 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -17,7 +17,7 @@ RUN apt update && apt -y install software-properties-common && add-apt-repositor
 
 # run Ansible commands
 COPY ./requirements.yaml ./playbook.yaml ./
-RUN ansible-galaxy install -r requirements.yaml && ansible-playbook -i,localhost playbook.yaml --tags "all" && rm -f ./*.yaml
+RUN ansible-galaxy install -r requirements.yaml && ansible-playbook -vvvv -i,localhost playbook.yaml --tags "install_utilities" && rm -f ./*.yaml
 
 # Custom Desktop Background - replace bg_custom.png on disk with your own background image
 COPY ./bg_fairy_penguins_1600x800.png /usr/share/backgrounds/bg_default.png
diff --git a/install_files/nix-root-profile.sh b/install_files/nix-root-profile.sh
new file mode 100644
index 0000000..b0ae655
--- /dev/null
+++ b/install_files/nix-root-profile.sh
@@ -0,0 +1,5 @@
+#!/usr/bin/bash
+# Add Nix root profile to the system PATH
+if [ -d /nix/var/nix/profiles/per-user/root/bin ]; then
+    export PATH="/nix/var/nix/profiles/per-user/root/bin:$PATH"
+fi
diff --git a/playbook.yaml b/playbook.yaml
index 7f7ee61..8d9f490 100644
--- a/playbook.yaml
+++ b/playbook.yaml
@@ -78,98 +78,106 @@
     - role: webarchitect609.google_chrome
 
 -
-  # install firefox
+  # install keychain, git, nix, and @capsulecorplab .vimrc and .gitconfig
   hosts: localhost
   connection: local
   gather_facts: yes
   tags:
-    - install_firefox
-
-  vars:
-    firefox_profiles:
-      default:
-        extensions:
-          - ublock-origin
-        preferences:
-          network.cookie.cookieBehavior: 1
-          privacy.donottrackheader.enabled: true
-          datareporting.healthreport.uploadEnabled: false
-      secondprofile:
-        extensions:
-          - adblock-plus
-        preferences:
-          privacy.donottrackheader.enabled: false
-          privacy.trackingprotection.enabled: false
-          signon.rememberSignons: false
-          datareporting.healthreport.uploadEnabled: false
-
-  tasks:
-  - name: Get disk usage
-    shell: df -h
-    register: disk_usage
-  - name: Display disk usage
-    debug:
-      msg: "{{ disk_usage.stdout }}"
-
-  pre_tasks:
-  - name: Update apt packages
-    apt:
-      update_cache: yes
-
-  roles:
-    - role: staticdev.firefox
-
--
-  # install keychain, git, and @capsulecorplab .vimrc and .gitconfig
-  hosts: localhost
-  connection: local
-  gather_facts: yes
-  tags: install_utilities
+  - install_utilities
+  - install_python_packages
 
   vars:
+    nixos_release: "26.05"
+    nix_version: "2.35.3"
+    nix_installer_dir: /tmp/nix-{{ nix_version }}-x86_64-linux
     git_version: "2.43.0"
-    git_version_to_install: "1:{{ git_version }}-1ubuntu7"
     keychain_version: "2.8.5"
-    keychain_version_to_install: "{{ keychain_version }}-4"
     keychain_version_expected: "{{ keychain_version }}.."
 
   tasks:
-  - name: Add git PPA
-    shell: add-apt-repository ppa:git-core/ppa
-  - name: Install git
+  # - name: Install nix-bin # see https://moonpiedumplings.github.io/projects/setting-up-kasm/#customized-kasm-images
+  #   apt:
+  #     name: nix-bin
+  #     update_cache: yes
+  # - name: Create {{ nix_install_dir }} directory with chmod 755
+  #   file:
+  #     path: "{{ nix_install_dir }}"
+  #     state: directory
+  #     mode: '0755'
+  - name: Create /nix directory with chmod 755
+    file:
+      path: /nix
+      state: directory
+      mode: '0755'
+  - name: Install build dependencies
     apt:
-      name: git
-  - name: Install Git Bash Completion
-    apt:
-      name: bash-completion
-      update_cache: yes
-  - name: Install Keychain
-    apt:
-      name: "keychain={{ keychain_version_to_install }}"
+      name:
+        - xz-utils          # unpacks binary tarball
+        - build-essential   # gcc, make, etc.
+        - libssl-dev        # for OpenSSL
+        - ca-certificates
       update_cache: yes
-  - name: install ping
+  - name: Install Sudo
     apt:
-      name: iputils-ping
+      name: sudo
       update_cache: yes
-  - name: Get git version
-    shell: git version | sed 's/[[:alpha:]|(|[:space:]]//g'
-    register: installed_git_version
-  - name: Get keychain version
+  - name: Download nix tarball {{ nix_version }}
+    shell: curl -L https://releases.nixos.org/nix/nix-{{ nix_version }}/nix-{{ nix_version }}-x86\_64-linux.tar.xz -o {{ nix_installer_dir }}.tar.xz
+  - name: Extract nix tarball to /tmp
     shell:
-      cmd: keychain -V 2> >(grep -i keychain) 2> >(sed 's/[[:alpha:]|(|[:space:]]//g') | fgrep '*' | sed 's/[*~://]//g'
+      cmd: "tar -xvf {{ nix_installer_dir }}.tar.xz"
+      chdir: /tmp
       executable: /bin/bash
-    register: installed_keychain_version
-  - name: Display git and keychain versions
-    debug:
-      msg: "git = {{ installed_git_version.stdout }} | keychain = {{ installed_keychain_version.stdout }}"
-  - name: Test git version
-    fail:
-      msg: "Git Version Error: Expected {{ git_version }} | Found {{ installed_git_version.stdout }}"
-    when: installed_git_version.stdout != git_version
-  - name: Test keychain version
-    fail:
-      msg: "Keychain Version Error: Expected {{ keychain_version_expected }} | Found {{ installed_keychain_version.stdout }}"
-    when: installed_keychain_version.stdout != keychain_version_expected
+    args:
+      creates: "{{ nix_installer_dir }}/install"
+  - name: Install (single-user) nix using classic nix installer with --fallback (i.e., build from source to dynamically pull OpenSSL version)
+    shell:
+      cmd: ./install --no-daemon --fallback
+      chdir: "{{ nix_installer_dir }}"
+      executable: /bin/bash
+  # - name: Add kasm-user to nix-users group
+  #   shell: usermod -aG nix-users kasm-user
+  # - name: Remove existing /nix/var/nix/profiles/per-user/root directory
+  #   shell: rm -rf /nix/var/nix/profiles/per-user/root
+  # - name: Create temporary first-generation directory
+  #   shell: mkdir -p /nix/var/nix/profiles/per-user/root-gen-0
+  # - name: Symlink /nix/var/nix/profiles/per-user/root to /nix/var/nix/profiles/per-user/root-gen-0
+  #   shell: ln -sfn /nix/var/nix/profiles/per-user/root-gen-0 /nix/var/nix/profiles/per-user/root
+  # - name: Copy script for exporting nix root profile to path to /etc/profile.d/nix-root-profile.sh
+  #   copy:
+  #     src: /home/kasm-default-profile/install_files/nix-root-profile.sh
+  #     dest: /etc/profile.d/nix-root-profile.sh
+  #     remote_src: yes
+  #     owner: root
+  #     group: root
+  #     mode: '0755'
+  # - name: Install git {{ git_version }} with nix
+  #   shell: nix profile install nixpkgs/release-{{ nixos_release }}#git --extra-experimental-features 'nix-command flakes' --profile /nix/var/nix/profiles/per-user/root
+  # - name: Install Git Bash Completion
+  #   shell: nix profile install nixpkgs/release-{{ nixos_release }}#bash-completion --extra-experimental-features 'nix-command flakes' --profile /nix/var/nix/profiles/per-user/root
+  # - name: Install Keychain
+  #   shell: nix profile install nixpkgs/release-{{ nixos_release }}#keychain --extra-experimental-features 'nix-command flakes' --profile /nix/var/nix/profiles/per-user/root
+  # - name: install ping
+  #   shell: nix profile install nixpkgs#unixtools.ping --extra-experimental-features 'nix-command flakes' --profile /nix/var/nix/profiles/per-user/root
+  # - name: Get keychain version
+  #   shell:
+  #     cmd: keychain -V 2> >(grep -i keychain) 2> >(sed 's/[[:alpha:]|(|[:space:]]//g') | fgrep '*' | sed 's/[*~://]//g'
+  #     executable: /bin/bash
+  #   register: installed_keychain_version
+  # - name: Get git version
+  #   shell: git version | sed 's/[[:alpha:]|(|[:space:]]//g'
+  #   register: installed_git_version
+  # - name: Display git and keychain versions
+  #   debug:
+  #     msg: "git = {{ installed_git_version.stdout }} | keychain = {{ installed_keychain_version.stdout }}"
+  # - name: Test git version
+  #   fail:
+  #     msg: "Git Version Error: Expected {{ git_version }} | Found {{ installed_git_version.stdout }}"
+  #   when: installed_git_version.stdout != git_version
+  #- name: Test keychain version
+  #  fail:
+  #    msg: "Keychain Version Error: Expected {{ keychain_version_expected }} | Found {{ installed_keychain_version.stdout }}"
+  #  when: installed_keychain_version.stdout != keychain_version_expected
   - name: Install @capsulecorplab .vimrc
     get_url:
       url: https://gist.githubusercontent.com/capsulecorplab/495058e7a57ed8adaed3c40c80d09739/raw/4a6e6f6ff92b96919be111c9cbb5a4a21ab472d2/.vimrc
@@ -190,6 +198,8 @@
   hosts: localhost
   connection: local
   gather_facts: yes
+  tags:
+  - install_python_packages
 
   tasks:
   - name: Update OS to point python to python3
@@ -205,6 +215,10 @@
       break_system_packages: true
       name:
         - pint
+        - voila
+        - notebook==6.5.7
+        - jupyterlab==3.6.8
+      extra_args: --ignore-installed
   - name: Get disk usage
     shell: df -h
     register: disk_usage
@@ -369,12 +383,13 @@
 
   roles:
     - role: gantsign.visual-studio-code
+      visual_studio_code_version: "1.91.1*"
       users:
         - username: "dev"
           visual_studio_code_extensions:
             - ms-python.python
             - dendron.dendron
-            - foam.foam-vscode
+            #- foam.foam-vscode
           visual_studio_code_settings_overwrite: yes
           visual_studio_code_settings: {
             "extensions.ignoreRecommendations": true,
diff --git a/requirements.yaml b/requirements.yaml
index 46d4674..d33accb 100644
--- a/requirements.yaml
+++ b/requirements.yaml
@@ -3,6 +3,5 @@
 - irixjp.role_example_hello           # https://galaxy.ansible.com/irixjp/role_example_hello
 - grzegorznowak.nvm_node              # https://galaxy.ansible.com/grzegorznowak/nvm_node
 - webarchitect609.google_chrome       # https://galaxy.ansible.com/webarchitect609/google_chrome
-- staticdev.firefox                   # https://galaxy.ansible.com/staticdev/firefox
 - gantsign.visual-studio-code         # https://galaxy.ansible.com/gantsign/visual-studio-code
 ...