diff --git a/neovim/config/plugins/diffview.lua b/neovim/config/plugins/diffview.lua
new file mode 100644
index 0000000..f9630bb
--- /dev/null
+++ b/neovim/config/plugins/diffview.lua
@@ -0,0 +1,12 @@
+vim.pack.add({ 'https://github.com/sindrets/diffview.nvim' })
+
+require('diffview').setup()
+
+local function map(lhs, rhs, desc)
+  vim.keymap.set('n', lhs, rhs, { desc = desc })
+end
+
+map('<leader>gd', '<Cmd>DiffviewOpen<CR>', 'Diff against index')
+map('<leader>gc', '<Cmd>DiffviewClose<CR>', 'Close diff view')
+map('<leader>gh', '<Cmd>DiffviewFileHistory %<CR>', 'File history')
+map('<leader>gH', '<Cmd>DiffviewFileHistory<CR>', 'Branch history')
diff --git a/neovim/config/plugins/init.lua b/neovim/config/plugins/init.lua
index 708bbb7..fc2c8eb 100644
--- a/neovim/config/plugins/init.lua
+++ b/neovim/config/plugins/init.lua
@@ -1,3 +1,4 @@
+require('config.plugins.diffview')
 require('config.plugins.fzf-lua')
 require('config.plugins.gitsigns')
 require('config.plugins.nvim-tree')
diff --git a/neovim/config/plugins/which-key.lua b/neovim/config/plugins/which-key.lua
index 634bd35..a663754 100644
--- a/neovim/config/plugins/which-key.lua
+++ b/neovim/config/plugins/which-key.lua
@@ -8,6 +8,7 @@ wk.setup()
 wk.add({
   { '<leader>d', group = 'diagnostics' },
   { '<leader>f', group = 'find' },
+  { '<leader>g', group = 'diff' },
   { '<leader>h', group = 'hunks' },
   { '<leader>t', group = 'toggles' },
 })
diff --git a/neovim/nvim-pack-lock.json b/neovim/nvim-pack-lock.json
index 02bc8b6..335a0f8 100644
--- a/neovim/nvim-pack-lock.json
+++ b/neovim/nvim-pack-lock.json
@@ -1,5 +1,9 @@
 {
   "plugins": {
+    "diffview.nvim": {
+      "rev": "4516612fe98ff56ae0415a259ff6361a89419b0a",
+      "src": "https://github.com/sindrets/diffview.nvim"
+    },
     "fzf-lua": {
       "rev": "8671012a7b2a1648595952c655039d51fb301c14",
       "src": "https://github.com/ibhagwan/fzf-lua"
diff --git a/tmux b/tmux
index 49182f0..45329ff 100644
--- a/tmux
+++ b/tmux
@@ -14,6 +14,10 @@ set -g renumber-windows on
 # don't detach when closing a window if other windows remain
 set -g detach-on-destroy off
 
+# prompt for a name and create a session in one step, instead of
+# `<prefix> :` then `new -s name`
+bind-key S command-prompt -p "New session name:" "new-session -s '%%'"
+
 # reload config file (change file location to your the tmux.conf you want to use)
 unbind r
 bind r source-file ~/.tmux.conf
@@ -51,5 +55,7 @@ set-hook -g client-dark-theme 'source-file ~/.tmux-dark.conf'
 # client attaches. Sourcing is idempotent, so the overlap is harmless.
 set-hook -g client-attached 'if -F "#{==:#{client_theme},light}" "source-file ~/.tmux-light.conf" "source-file ~/.tmux-dark.conf"'
 
-# Default before any client has attached and reported a theme.
-source-file ~/.tmux-dark.conf
+# Default before any client has attached and reported a theme. This also
+# runs on manual reload (`r` below), so check the invoking client's theme
+# rather than always falling back to dark and clobbering a light session.
+if -F "#{==:#{client_theme},light}" "source-file ~/.tmux-light.conf" "source-file ~/.tmux-dark.conf"