diff --git a/README.md b/README.md
index 33c2453..ae9cf19 100644
--- a/README.md
+++ b/README.md
@@ -120,7 +120,7 @@ single-chord access (configurable via `keymaps.exercise`):
 | `Ctrl-n`  | Next exercise                   |
 | `Ctrl-p`  | Previous exercise               |
 | `Ctrl-k`  | Skip exercise                   |
-| `Ctrl-i`  | Show hints                      |
+| `Ctrl-g`  | Show hints                      |
 | `Ctrl-l`  | View solution (split)           |
 | `Ctrl-d`  | Show description                |
 | `Ctrl-b`  | Open browser                    |
@@ -158,7 +158,7 @@ Or from Neovim: `:CP generate` (prompts for topic, count, difficulty, and engine
 
 ### AI Hints
 
-When enabled, `Ctrl-i` generates a context-aware hint using a Hugging Face model
+When enabled, `Ctrl-g` generates a context-aware hint using a Hugging Face model
 instead of showing static hints. The hint is based on your current buffer and the
 reference solution.
 
diff --git a/doc/code-practice.txt b/doc/code-practice.txt
index 04b64cc..6e5b4f4 100644
--- a/doc/code-practice.txt
+++ b/doc/code-practice.txt
@@ -98,7 +98,7 @@ Tab completion is supported: type `:CP <Tab>` to explore.
                         schema matches `test/example_exercises.json` in the
                         plugin source.
 
-:CP import! {path}      Replace all existing exercises, test cases, attempts,
+:CP! import {path}      Replace all existing exercises, test cases, attempts,
                         and theory options with the contents of {path}.
 
 :CP generate            Interactively generate exercises via Hugging Face
@@ -146,7 +146,7 @@ via `keymaps.exercise` in config.
     `Ctrl-n`         Next exercise
     `Ctrl-p`         Previous exercise
     `Ctrl-k`         Skip exercise
-    `Ctrl-i`         Show hints
+    `Ctrl-g`         Show hints
     `Ctrl-l`         View solution
     `Ctrl-d`         Show description
     `Ctrl-b`         Open browser
@@ -181,8 +181,6 @@ Options are merged with |vim.tbl_deep_extend()|.
 
       runner = {
         timeout = 5,            -- seconds per test case
-        show_time = true,
-        auto_save = true,
       },
 
       ai_hints = {
@@ -202,7 +200,7 @@ Options are merged with |vim.tbl_deep_extend()|.
         },
         exercise = {
           run_tests = "<C-t>",
-          show_hint = "<C-i>",
+          show_hint = "<C-g>",
           view_solution = "<C-l>",
           show_description = "<C-d>",
           next_exercise = "<C-n>",
diff --git a/lua/code-practice/browser.lua b/lua/code-practice/browser.lua
index 2585a37..5008d54 100644
--- a/lua/code-practice/browser.lua
+++ b/lua/code-practice/browser.lua
@@ -275,6 +275,16 @@ local function update_display()
   vim.bo[preview_buf].modifiable = false
   vim.bo[list_buf].readonly = true
   vim.bo[preview_buf].readonly = true
+
+  local list_win = state.popup.list.winid
+  if
+    list_win
+    and vim.api.nvim_win_is_valid(list_win)
+    and state.selected_index > 0
+    and state.selected_index <= #list_lines
+  then
+    vim.api.nvim_win_set_cursor(list_win, { state.selected_index, 0 })
+  end
 end
 
 function browser.refresh()
diff --git a/lua/code-practice/config.lua b/lua/code-practice/config.lua
index 3fe4915..14b49a5 100644
--- a/lua/code-practice/config.lua
+++ b/lua/code-practice/config.lua
@@ -31,8 +31,6 @@ config.defaults = {
 
   runner = {
     timeout = 5,
-    show_time = true,
-    auto_save = true,
   },
 
   ai_hints = {
@@ -52,7 +50,7 @@ config.defaults = {
     },
     exercise = {
       run_tests = "<C-t>",
-      show_hint = "<C-i>",
+      show_hint = "<C-g>",
       view_solution = "<C-l>",
       show_description = "<C-d>",
       next_exercise = "<C-n>",
@@ -67,6 +65,7 @@ config.config = vim.deepcopy(config.defaults)
 
 function config.setup(user_config)
   user_config = user_config or {}
+  config.defaults.engines = build_engine_defaults()
   config.config = vim.tbl_deep_extend("force", config.defaults, user_config)
 
   vim.fn.mkdir(config.config.storage.home, "p")
diff --git a/lua/code-practice/engines.lua b/lua/code-practice/engines.lua
index f253da4..a8591f0 100644
--- a/lua/code-practice/engines.lua
+++ b/lua/code-practice/engines.lua
@@ -23,8 +23,8 @@ engines.registry = {
       enabled = true,
       cmd = "python3",
     },
-    run_cmd = function(cfg)
-      return cfg.cmd or "python3"
+    run_cmd = function(cfg, file)
+      return { cfg.cmd or "python3", file }
     end,
     wrap_test = function(code, input)
       local call = (input or ""):match("^%s*$") and "solution()" or ("solution(" .. input .. ")")
diff --git a/lua/code-practice/help.lua b/lua/code-practice/help.lua
index be3cb0c..c36239d 100644
--- a/lua/code-practice/help.lua
+++ b/lua/code-practice/help.lua
@@ -1,13 +1,7 @@
 -- Code Practice - Keymap Cheat-Sheet
-local ok, Popup = pcall(require, "nui.popup")
-if not ok then
-  vim.notify("[code-practice] nui.nvim not found. Install MunifTanjim/nui.nvim", vim.log.levels.ERROR)
-  return {}
-end
-
 local config = require("code-practice.config")
 local engines = require("code-practice.engines")
-local popup_util = require("code-practice.popup")
+local popup = require("code-practice.popup")
 
 local help = {}
 
@@ -28,42 +22,20 @@ end
 function help.show()
   local width = math.min(90, vim.o.columns - 4)
   local height = math.min(30, vim.o.lines - 4)
-  local row = math.max(1, math.floor((vim.o.lines - height) / 2))
-  local col = math.max(1, math.floor((vim.o.columns - width) / 2))
-
-  local popup = Popup({
-    relative = "editor",
-    position = {
-      row = row,
-      col = col,
-    },
-    size = {
-      width = width,
-      height = height,
-    },
-    border = {
-      style = "rounded",
-      text = {
-        top = " Keymaps ",
-        top_align = "center",
-      },
-    },
-    buf_options = {
-      modifiable = true,
-      readonly = false,
-    },
-    win_options = {
-      winhighlight = "Normal:Normal,FloatBorder:FloatBorder",
-    },
-  })
-
-  popup:mount()
-  if popup.winid then
-    vim.api.nvim_set_current_win(popup.winid)
-  end
-  vim.cmd("stopinsert")
+
+  local bufnr, _, close_fn = popup.open_float({ width = width, height = height, title = " Keymaps " })
 
   local km = config.get("keymaps.exercise", {})
+  local bkm = config.get("keymaps.browser", {})
+
+  -- Two-column row with the right column aligned to a fixed offset.
+  local function row(lkey, ldesc, rkey, rdesc)
+    local left = "  " .. pad(fmt_key(lkey), 19) .. ldesc
+    if rkey == nil and rdesc == nil then
+      return left
+    end
+    return pad(left, 54) .. pad(fmt_key(rkey), 17) .. (rdesc or "")
+  end
 
   local filter_lines = {}
   for _, name in ipairs(engines.list()) do
@@ -73,21 +45,22 @@ function help.show()
     end
   end
 
+  local open_key = bkm.open_item or bkm.open or "<CR>"
+
   local lines = {
     "",
     "  BROWSER",
     "  " .. string.rep("─", width - 4),
-    "  j / k            Move up / down                     Enter / o        Open exercise",
-    "  e                Filter by Easy difficulty          m                Filter by Medium",
-    "  h                Filter by Hard difficulty          a                Clear all filters",
+    row("j / k", "Move up / down", open_key .. " / o", "Open exercise"),
+    row(bkm.filter_easy or "e", "Filter by Easy difficulty", bkm.filter_medium or "m", "Filter by Medium"),
+    row(bkm.filter_hard or "h", "Filter by Hard difficulty", bkm.filter_all or "a", "Clear all filters"),
   }
 
   for _, fl in ipairs(filter_lines) do
     table.insert(lines, fl)
   end
 
-  table.insert(lines, "  q / Esc          Close browser")
-  table.insert(lines, "  ?                Show this cheat-sheet")
+  table.insert(lines, row(bkm.close or "q", "Close browser", "?", "Show this cheat-sheet"))
 
   local exercise_lines = {
     "",
@@ -122,22 +95,16 @@ function help.show()
     table.insert(lines, el)
   end
 
-  vim.bo[popup.bufnr].modifiable = true
-  vim.api.nvim_buf_set_lines(popup.bufnr, 0, -1, false, lines)
-  vim.bo[popup.bufnr].modifiable = false
+  popup.set_lines(bufnr, lines)
 
   local ns_help = vim.api.nvim_create_namespace("code_practice_help")
   for i, line in ipairs(lines) do
     if line:match("^  [A-Z]") and not line:match("^  See") and not line:match("^  Press") then
-      vim.api.nvim_buf_add_highlight(popup.bufnr, ns_help, "Underlined", i - 1, 0, -1)
+      vim.api.nvim_buf_add_highlight(bufnr, ns_help, "Underlined", i - 1, 0, -1)
     end
   end
 
-  popup_util.map_close(popup.bufnr, function()
-    if popup and popup.winid and vim.api.nvim_win_is_valid(popup.winid) then
-      popup:unmount()
-    end
-  end)
+  popup.map_close(bufnr, close_fn)
 end
 
 return help
diff --git a/lua/code-practice/importer.lua b/lua/code-practice/importer.lua
index 6abe594..b09a70d 100644
--- a/lua/code-practice/importer.lua
+++ b/lua/code-practice/importer.lua
@@ -4,6 +4,20 @@ local utils = require("code-practice.utils")
 
 local importer = {}
 
+-- sqlite.lua's stmt:bind treats strings matching "^[%S]+%(.*%)$" as SQL
+-- functions and skips binding them (see kkharji/sqlite.lua#87).  Values like
+-- "O(n)" or "O(n log n)" trigger this and silently become NULL.  We work
+-- around it by formatting values directly into the SQL string.
+local function sql_escape(val)
+  if val == nil then
+    return "NULL"
+  elseif type(val) == "number" then
+    return tostring(val)
+  else
+    return "'" .. tostring(val):gsub("'", "''") .. "'"
+  end
+end
+
 function importer.import(json_path, opts)
   opts = opts or {}
 
@@ -101,14 +115,13 @@ function importer.import(json_path, opts)
         local opt_ok, opt_err = pcall(
           conn.eval,
           conn,
-          [[INSERT INTO theory_options (exercise_id, option_number, option_text, is_correct)
-            VALUES (:eid, :num, :text, :correct)]],
-          {
-            eid = ex.id,
-            num = opt.option_number,
-            text = opt.option_text,
-            correct = opt.is_correct == 1 and 1 or 0,
-          }
+          string.format(
+            "INSERT INTO theory_options (exercise_id, option_number, option_text, is_correct) VALUES (%s, %s, %s, %s)",
+            sql_escape(ex.id),
+            sql_escape(opt.option_number),
+            sql_escape(opt.option_text),
+            sql_escape((opt.is_correct == 1 or opt.is_correct == true) and 1 or 0)
+          )
         )
         if opt_ok then
           counts.theory_options = counts.theory_options + 1
diff --git a/lua/code-practice/init.lua b/lua/code-practice/init.lua
index 1f80df0..fb4f15a 100644
--- a/lua/code-practice/init.lua
+++ b/lua/code-practice/init.lua
@@ -239,11 +239,9 @@ function code_practice.show_stats()
     "",
   }
 
-  local bufnr, winid = popup.open_float({ width = 0.3, height = 0.3, title = " Statistics " })
+  local bufnr, _, close_fn = popup.open_float({ width = 0.3, height = 0.3, title = " Statistics " })
   popup.set_lines(bufnr, lines)
-  popup.map_close(bufnr, function()
-    utils.close_win(winid)
-  end)
+  popup.map_close(bufnr, close_fn)
 end
 
 function code_practice.get_current_exercise_id()
@@ -264,11 +262,9 @@ local function show_static_hints(exercise)
     table.insert(lines, "")
   end
 
-  local bufnr, winid = popup.open_float({ width = 0.5, height = 0.4, title = " Hints " })
+  local bufnr, _, close_fn = popup.open_float({ width = 0.5, height = 0.4, title = " Hints " })
   popup.set_lines(bufnr, lines)
-  popup.map_close(bufnr, function()
-    utils.close_win(winid)
-  end)
+  popup.map_close(bufnr, close_fn)
 end
 
 function code_practice.show_hints()
@@ -289,11 +285,9 @@ function code_practice.show_hints()
   end
 
   local buffer_content = utils.get_buffer_content(vim.api.nvim_get_current_buf())
-  local hint_bufnr, hint_winid = popup.open_float({ width = 0.5, height = 0.4, title = " AI Hint " })
+  local hint_bufnr, _, hint_close = popup.open_float({ width = 0.5, height = 0.4, title = " AI Hint " })
   popup.set_lines(hint_bufnr, { "", "  Generating hint..." })
-  popup.map_close(hint_bufnr, function()
-    utils.close_win(hint_winid)
-  end)
+  popup.map_close(hint_bufnr, hint_close)
 
   local ai_hints = require("code-practice.ai_hints")
   ai_hints.generate(exercise, buffer_content, function(hint_text, err)
@@ -303,7 +297,7 @@ function code_practice.show_hints()
 
     if err then
       utils.notify("AI hint failed: " .. err, "error")
-      utils.close_win(hint_winid)
+      hint_close()
       show_static_hints(exercise)
       return
     end
@@ -370,11 +364,9 @@ function code_practice.show_description()
     footer = "Press q, <Esc>, or <Enter> to close",
   })
 
-  local bufnr, winid = popup.open_float({ filetype = "markdown", title = " Description " })
+  local bufnr, _, close_fn = popup.open_float({ filetype = "markdown", title = " Description " })
   popup.set_lines(bufnr, lines)
-  popup.map_close(bufnr, function()
-    utils.close_win(winid)
-  end)
+  popup.map_close(bufnr, close_fn)
 end
 
 function code_practice.show_help()
diff --git a/lua/code-practice/manager.lua b/lua/code-practice/manager.lua
index 89f0181..da49c74 100644
--- a/lua/code-practice/manager.lua
+++ b/lua/code-practice/manager.lua
@@ -122,6 +122,104 @@ function manager.get_stats()
   return db.get_stats()
 end
 
+local function build_exercise_content(exercise)
+  local lines, add_meta = manager.build_header_lines(exercise, "Exercise")
+  local run_key = config.get("keymaps.exercise.run_tests", "<C-t>")
+
+  local theory_options = nil
+  if exercise.engine == "theory" then
+    theory_options = exercise.options or db.get_theory_options(exercise.id)
+    if theory_options and #theory_options > 0 then
+      add_meta("Options:")
+      for _, opt in ipairs(theory_options) do
+        add_meta(string.format("%d. %s", opt.option_number, opt.option_text))
+      end
+      add_meta("")
+      add_meta("Press 1-" .. #theory_options .. " to select your answer, then " .. run_key .. " to check.")
+    end
+  else
+    add_meta("Modify the code below, then " .. run_key .. " to run tests.")
+  end
+
+  add_meta("")
+  add_meta(string.rep("-", 40))
+  add_meta("")
+
+  local starter = exercise.starter_code or ""
+  if exercise.engine == "theory" and theory_options and #theory_options > 0 then
+    starter = ""
+  end
+  if exercise.engine == "theory" then
+    if starter ~= "" then
+      for _, line in ipairs(utils.split_lines(starter)) do
+        table.insert(lines, line)
+      end
+    end
+    local has_answer_line = false
+    for _, line in ipairs(lines) do
+      if line:match("^[Aa]nswer:") then
+        has_answer_line = true
+        break
+      end
+    end
+    if not has_answer_line then
+      table.insert(lines, "Answer: ")
+    end
+  else
+    for _, line in ipairs(utils.split_lines(starter)) do
+      table.insert(lines, line)
+    end
+  end
+
+  return table.concat(lines, "\n")
+end
+
+local function setup_theory_keymaps(bufnr, exercise)
+  if vim.b[bufnr].code_practice_theory_keymaps then
+    return
+  end
+  vim.b[bufnr].code_practice_theory_keymaps = true
+
+  local opts_by_num = {}
+  for _, opt in ipairs(exercise.options or {}) do
+    opts_by_num[opt.option_number] = opt.option_text
+  end
+
+  for num, text in pairs(opts_by_num) do
+    vim.keymap.set("n", tostring(num), function()
+      local line_count = vim.api.nvim_buf_line_count(bufnr)
+      for i = 0, line_count - 1 do
+        local line = vim.api.nvim_buf_get_lines(bufnr, i, i + 1, false)[1]
+        if line and line:match("^Answer:") then
+          vim.bo[bufnr].modifiable = true
+          vim.api.nvim_buf_set_lines(bufnr, i, i + 1, false, {
+            string.format("Answer: %d  [%s]", num, text),
+          })
+          utils.notify(string.format("Selected option %d: %s", num, text), "info")
+          return
+        end
+      end
+    end, { buffer = bufnr, noremap = true, nowait = true })
+  end
+end
+
+local function is_floating(win)
+  local ok, cfg = pcall(vim.api.nvim_win_get_config, win)
+  return ok and cfg and cfg.relative and cfg.relative ~= ""
+end
+
+local function focus_non_floating_window()
+  if not is_floating(vim.api.nvim_get_current_win()) then
+    return
+  end
+  for _, win in ipairs(vim.api.nvim_list_wins()) do
+    if not is_floating(win) then
+      vim.api.nvim_set_current_win(win)
+      return
+    end
+  end
+end
+
 function manager.open_exercise(id)
   local exercise = manager.get_exercise(id)
   if not exercise then
@@ -150,103 +248,17 @@ function manager.open_exercise(id)
   if needs_content then
     vim.bo[bufnr].modifiable = true
     vim.bo[bufnr].readonly = false
-
-    local lines, add_meta = manager.build_header_lines(exercise, "Exercise")
-    local run_key = config.get("keymaps.exercise.run_tests", "<C-t>")
-
-    local theory_options = nil
-    if exercise.engine == "theory" then
-      theory_options = exercise.options or db.get_theory_options(exercise.id)
-      if theory_options and #theory_options > 0 then
-        add_meta("Options:")
-        for _, opt in ipairs(theory_options) do
-          add_meta(string.format("%d. %s", opt.option_number, opt.option_text))
-        end
-        add_meta("")
-        add_meta("Press 1-" .. #theory_options .. " to select your answer, then " .. run_key .. " to check.")
-      end
-    else
-      add_meta("Modify the code below, then " .. run_key .. " to run tests.")
-    end
-
-    add_meta("")
-    add_meta(string.rep("-", 40))
-    add_meta("")
-
-    local starter = exercise.starter_code or ""
-    if exercise.engine == "theory" and theory_options and #theory_options > 0 then
-      starter = ""
-    end
-    if exercise.engine == "theory" then
-      if starter ~= "" then
-        for _, line in ipairs(utils.split_lines(starter)) do
-          table.insert(lines, line)
-        end
-      end
-      local has_answer_line = false
-      for _, line in ipairs(lines) do
-        if line:match("^[Aa]nswer:") then
-          has_answer_line = true
-          break
-        end
-      end
-      if not has_answer_line then
-        table.insert(lines, "Answer: ")
-      end
-    else
-      for _, line in ipairs(utils.split_lines(starter)) do
-        table.insert(lines, line)
-      end
-    end
-
-    local content = table.concat(lines, "\n")
-    utils.set_buffer_content(bufnr, content)
+    utils.set_buffer_content(bufnr, build_exercise_content(exercise))
   end
 
   vim.b[bufnr].code_practice_exercise_id = id
   vim.b[bufnr].code_practice_engine = exercise.engine
 
-  if exercise.engine == "theory" and not vim.b[bufnr].code_practice_theory_keymaps then
-    vim.b[bufnr].code_practice_theory_keymaps = true
-
-    local opts_by_num = {}
-    for _, opt in ipairs(exercise.options or {}) do
-      opts_by_num[opt.option_number] = opt.option_text
-    end
-
-    for num, text in pairs(opts_by_num) do
-      vim.keymap.set("n", tostring(num), function()
-        local line_count = vim.api.nvim_buf_line_count(bufnr)
-        for i = 0, line_count - 1 do
-          local line = vim.api.nvim_buf_get_lines(bufnr, i, i + 1, false)[1]
-          if line and line:match("^Answer:") then
-            vim.bo[bufnr].modifiable = true
-            vim.api.nvim_buf_set_lines(bufnr, i, i + 1, false, {
-              string.format("Answer: %d  [%s]", num, text),
-            })
-            utils.notify(string.format("Selected option %d: %s", num, text), "info")
-            return
-          end
-        end
-      end, { buffer = bufnr, noremap = true, nowait = true })
-    end
-  end
-
-  local current_win = vim.api.nvim_get_current_win()
-  local function is_floating(win)
-    local ok, cfg = pcall(vim.api.nvim_win_get_config, win)
-    return ok and cfg and cfg.relative and cfg.relative ~= ""
-  end
-
-  if is_floating(current_win) then
-    for _, win in ipairs(vim.api.nvim_list_wins()) do
-      if not is_floating(win) then
-        vim.api.nvim_set_current_win(win)
-        break
-      end
-    end
+  if exercise.engine == "theory" then
+    setup_theory_keymaps(bufnr, exercise)
   end
 
+  focus_non_floating_window()
   vim.api.nvim_set_current_buf(bufnr)
 
   return bufnr
diff --git a/lua/code-practice/popup.lua b/lua/code-practice/popup.lua
index c4a59c6..1194816 100644
--- a/lua/code-practice/popup.lua
+++ b/lua/code-practice/popup.lua
@@ -23,10 +23,10 @@ function popup.open_float(opts)
   opts = opts or {}
   local ui_border = require("code-practice.config").get("ui.border", "rounded")
 
-  local width_ratio = opts.width or 0.6
-  local height_ratio = opts.height or 0.6
-  local width = math.floor(vim.o.columns * width_ratio)
-  local height = math.floor(vim.o.lines * height_ratio)
+  local w = opts.width or 0.6
+  local h = opts.height or 0.6
+  local width = w >= 1 and math.floor(w) or math.floor(vim.o.columns * w)
+  local height = h >= 1 and math.floor(h) or math.floor(vim.o.lines * h)
 
   local border = { style = opts.border or ui_border }
   if opts.title then
@@ -44,7 +44,7 @@ function popup.open_float(opts)
     buf_options.filetype = opts.filetype
   end
 
-  local popup = NuiPopup({
+  local win = NuiPopup({
     relative = "editor",
     position = "50%",
     size = { width = width, height = height },
@@ -52,9 +52,20 @@ function popup.open_float(opts)
     buf_options = buf_options,
   })
 
-  popup:mount()
+  win:mount()
 
-  return popup.bufnr, popup.winid
+  if win.winid then
+    vim.api.nvim_set_current_win(win.winid)
+  end
+  vim.cmd("stopinsert")
+
+  local function close_fn()
+    if win.winid and vim.api.nvim_win_is_valid(win.winid) then
+      vim.api.nvim_win_close(win.winid, true)
+    end
+  end
+
+  return win.bufnr, win.winid, close_fn
 end
 
 function popup.set_lines(bufnr, lines)
diff --git a/lua/code-practice/results.lua b/lua/code-practice/results.lua
index f503172..f68405d 100644
--- a/lua/code-practice/results.lua
+++ b/lua/code-practice/results.lua
@@ -3,15 +3,15 @@ local config = require("code-practice.config")
 local popup = require("code-practice.popup")
 
 local results = {}
-results._winid = nil
+results._close_fn = nil
 results._bufnr = nil
 local ns = vim.api.nvim_create_namespace("code_practice_results")
 
 function results.close()
-  if results._winid and vim.api.nvim_win_is_valid(results._winid) then
-    vim.api.nvim_win_close(results._winid, true)
+  if results._close_fn then
+    results._close_fn()
   end
-  results._winid = nil
+  results._close_fn = nil
   results._bufnr = nil
 end
 
@@ -21,13 +21,9 @@ function results.show(result, on_next)
     return
   end
 
-  local bufnr, winid = popup.open_float()
+  local bufnr, _, close_fn = popup.open_float()
   results._bufnr = bufnr
-  results._winid = winid
-  if winid then
-    vim.api.nvim_set_current_win(winid)
-  end
-  vim.cmd("stopinsert")
+  results._close_fn = close_fn
 
   local lines = {}
   local function push(line)
@@ -61,18 +57,24 @@ function results.show(result, on_next)
     for i, r in ipairs(result.results) do
       local status = r.passed and "✓ PASS" or "✗ FAIL"
       local duration = r.duration and string.format(" (%.0fms)", r.duration) or ""
-      push(string.format("Test %d: %s%s", i, status, duration))
+      local hidden_tag = r.hidden and " (hidden)" or ""
+      push(string.format("Test %d: %s%s%s", i, status, hidden_tag, duration))
 
       if r.error then
         append_block("  Error: ", r.error)
         push("")
       elseif not r.passed then
-        if r.input then
-          append_block("  Input: ", r.input)
+        if r.hidden then
+          push("  (hidden test — input and expected output withheld)")
+          push("")
+        else
+          if r.input then
+            append_block("  Input: ", r.input)
+          end
+          append_block("  Expected: ", r.expected)
+          append_block("  Got: ", r.actual)
+          push("")
         end
-        append_block("  Expected: ", r.expected)
-        append_block("  Got: ", r.actual)
-        push("")
       end
     end
   elseif result.correct_option then
diff --git a/lua/code-practice/runner.lua b/lua/code-practice/runner.lua
index 4667fe0..7ecb5dd 100644
--- a/lua/code-practice/runner.lua
+++ b/lua/code-practice/runner.lua
@@ -95,7 +95,7 @@ local function build_test_result(i, test, jr, timeout_ms)
 end
 
 -- Generic interpreted-engine runner.  Works for any engine that provides
--- `wrap_test(code, input)` and `run_cmd(cfg)` in the registry.
+-- `wrap_test(code, input)` and `run_cmd(cfg, file)` in the registry.
 local function run_interpreted_async(eng, eng_name, exercise_id, code, callback)
   local test_cases = db.get_test_cases(exercise_id)
   if #test_cases == 0 then
@@ -106,7 +106,7 @@ local function run_interpreted_async(eng, eng_name, exercise_id, code, callback)
   local results = {}
   local all_passed = true
   local timeout_ms = config.get("runner.timeout", 5) * 1000
-  local cmd = eng.run_cmd(config.get("engines." .. eng_name, {}))
+  local cfg = config.get("engines." .. eng_name, {})
 
   local function run_case(i)
     if i > #test_cases then
@@ -118,7 +118,7 @@ local function run_interpreted_async(eng, eng_name, exercise_id, code, callback)
     local test = test_cases[i]
     utils.write_file(temp_file, eng.wrap_test(code, test.input or ""))
 
-    local job_id = run_job({ cmd, temp_file }, { timeout_ms = timeout_ms }, function(jr)
+    local job_id = run_job(eng.run_cmd(cfg, temp_file), { timeout_ms = timeout_ms }, function(jr)
       local entry, passed = build_test_result(i, test, jr, timeout_ms)
       if not passed then
         all_passed = false
diff --git a/plugin/code-practice.lua b/plugin/code-practice.lua
index 05ad381..d0b4623 100644
--- a/plugin/code-practice.lua
+++ b/plugin/code-practice.lua
@@ -43,66 +43,70 @@ vim.api.nvim_create_user_command("CP", function(opts)
       utils.notify("Import failed: " .. (err or "unknown"), "error")
     end
   elseif sub == "generate" then
-    local topic = vim.fn.input("Topic: ")
-    if not topic or topic == "" then
-      return
-    end
-    local count = vim.fn.input("Count [5]: ")
-    count = (count and count ~= "") and count or "5"
-    local difficulty = vim.fn.input("Difficulty (easy/medium/hard) [medium]: ")
-    difficulty = (difficulty and difficulty ~= "") and difficulty or "medium"
-    local engine_names = table.concat(require("code-practice.engines").list(), "/")
-    local engine = vim.fn.input("Engine (" .. engine_names .. ") [python]: ")
-    engine = (engine and engine ~= "") and engine or "python"
+    vim.ui.input({ prompt = "Topic: " }, function(topic)
+      if not topic or topic == "" then
+        return
+      end
+      vim.ui.input({ prompt = "Count (default 5): " }, function(count)
+        count = (count and count ~= "") and count or "5"
+        vim.ui.select({ "easy", "medium", "hard" }, { prompt = "Difficulty:" }, function(difficulty)
+          difficulty = difficulty or "medium"
+          local engine_list = require("code-practice.engines").list()
+          vim.ui.select(engine_list, { prompt = "Engine:" }, function(engine)
+            engine = engine or "python"
 
-    local plugin_dir = vim.fn.fnamemodify(debug.getinfo(1, "S").source:sub(2), ":h:h")
-    local script = plugin_dir .. "/tools/generate_exercises.py"
-    local db_path = require("code-practice.config").get("storage.db_path")
+            local plugin_dir = vim.fn.fnamemodify(debug.getinfo(1, "S").source:sub(2), ":h:h")
+            local script = plugin_dir .. "/tools/generate_exercises.py"
+            local db_path = require("code-practice.config").get("storage.db_path")
 
-    local tmp = vim.fn.tempname() .. ".toml"
-    local toml = string.format(
-      '[[exercises]]\ntopic = "%s"\nengine = "%s"\ndifficulty = "%s"\ncount = %s\n',
-      topic:gsub('"', '\\"'),
-      engine,
-      difficulty,
-      count
-    )
-    vim.fn.writefile(vim.split(toml, "\n"), tmp)
+            local tmp = vim.fn.tempname() .. ".toml"
+            local toml = string.format(
+              '[[exercises]]\ntopic = "%s"\nengine = "%s"\ndifficulty = "%s"\ncount = %s\n',
+              topic:gsub('"', '\\"'),
+              engine,
+              difficulty,
+              count
+            )
+            vim.fn.writefile(vim.split(toml, "\n"), tmp)
 
-    local cmd = { "uv", "run", script, tmp, "--db-path", db_path }
+            local cmd = { "uv", "run", script, tmp, "--db-path", db_path }
 
-    utils.notify("Generating exercises...")
+            utils.notify("Generating exercises...")
 
-    local output_lines = {}
-    vim.fn.jobstart(cmd, {
-      stdout_buffered = true,
-      stderr_buffered = true,
-      on_stdout = function(_, data)
-        if data then
-          vim.list_extend(output_lines, data)
-        end
-      end,
-      on_stderr = function(_, data)
-        if data then
-          vim.list_extend(output_lines, data)
-        end
-      end,
-      on_exit = function(_, exit_code)
-        vim.fn.delete(tmp)
-        vim.schedule(function()
-          local msg = table.concat(output_lines, "\n")
-          if exit_code == 0 then
-            utils.notify(msg)
-            local browser = require("code-practice.browser")
-            if browser.refresh then
-              browser.refresh()
-            end
-          else
-            utils.notify("Generation failed:\n" .. msg, "error")
-          end
+            local output_lines = {}
+            vim.fn.jobstart(cmd, {
+              stdout_buffered = true,
+              stderr_buffered = true,
+              on_stdout = function(_, data)
+                if data then
+                  vim.list_extend(output_lines, data)
+                end
+              end,
+              on_stderr = function(_, data)
+                if data then
+                  vim.list_extend(output_lines, data)
+                end
+              end,
+              on_exit = function(_, exit_code)
+                vim.fn.delete(tmp)
+                vim.schedule(function()
+                  local msg = table.concat(output_lines, "\n")
+                  if exit_code == 0 then
+                    utils.notify(msg)
+                    local browser = require("code-practice.browser")
+                    if browser.refresh then
+                      browser.refresh()
+                    end
+                  else
+                    utils.notify("Generation failed:\n" .. msg, "error")
+                  end
+                end)
+              end,
+            })
+          end)
         end)
-      end,
-    })
+      end)
+    end)
   else
     utils.notify("Unknown subcommand: " .. sub, "warn")
   end
diff --git a/test/test_flow.lua b/test/test_flow.lua
index 8ebffbd..19b55f1 100644
--- a/test/test_flow.lua
+++ b/test/test_flow.lua
@@ -875,6 +875,251 @@ test("AI hints: show_hints uses static path when disabled", function()
   assert_eq(found_generating, false, "should not trigger AI hints when disabled")
 end)
 
+-- 43. Popup: open_float focuses window in normal mode, Esc closes it
+test("Popup: open_float focuses in normal mode and Esc closes", function()
+  local popup_mod = require("code-practice.popup")
+  local utils = require("code-practice.utils")
+
+  local bufnr, winid = popup_mod.open_float({ width = 0.4, height = 0.3, title = " Test Popup " })
+  assert_truthy(bufnr, "bufnr nil")
+  assert_truthy(winid, "winid nil")
+
+  assert_eq(vim.api.nvim_get_current_win(), winid, "current window should be the popup")
+  assert_eq(vim.api.nvim_get_mode().mode, "n", "should be in normal mode")
+
+  popup_mod.map_close(bufnr, function()
+    utils.close_win(winid)
+  end)
+
+  vim.api.nvim_feedkeys(vim.api.nvim_replace_termcodes("<Esc>", true, false, true), "x", false)
+
+  assert_truthy(not vim.api.nvim_win_is_valid(winid), "popup window should be closed after Esc")
+end)
+
+-- 44. Importer: theory options with function-like text survive import
+test("Importer: theory options with parenthesised text survive replace import", function()
+  local importer = require("code-practice.importer")
+  local db_mod = require("code-practice.db")
+
+  local plugin_root = vim.fn.fnamemodify(debug.getinfo(1, "S").source:sub(2), ":h:h")
+  local fixture = plugin_root .. "/test/example_exercises.json"
+
+  local counts, err = importer.import(fixture, { replace = true })
+  assert_truthy(counts, "import returned nil: " .. tostring(err))
+  assert_gt(counts.theory_options, 0, "theory_options imported")
+
+  local conn = db_mod.connect()
+  local rows = conn:eval("SELECT COUNT(*) as count FROM theory_options")
+  local total = rows and (rows.count or (rows[1] and rows[1].count)) or 0
+  assert_gt(total, 0, "theory_options should exist after import, got " .. total)
+
+  local problematic = conn:eval(
+    "SELECT * FROM theory_options WHERE option_text LIKE '%(%' ORDER BY exercise_id, option_number"
+  )
+  if type(problematic) == "table" and problematic[1] then
+    for _, row in ipairs(problematic) do
+      assert_truthy(
+        row.option_text and row.option_text ~= "",
+        "option_text should not be empty for exercise " .. row.exercise_id .. " option " .. row.option_number
+      )
+    end
+  end
+end)
+
+-- 45. Theory buffer: options and Answer line are present
+test("Theory buffer: options and Answer line displayed", function()
+  local db_mod = require("code-practice.db")
+  local mgr = require("code-practice.manager")
+
+  local theory = db_mod.get_all_exercises({ engine = "theory" })
+  if #theory == 0 then
+    skip("no theory exercises in seed data")
+  end
+
+  local ex_id = theory[1].id
+  local opts = db_mod.get_theory_options(ex_id)
+  if #opts == 0 then
+    skip("no theory options for exercise " .. ex_id)
+  end
+
+  local bufnr = mgr.open_exercise(ex_id)
+  assert_truthy(bufnr, "buffer nil")
+
+  local lines = vim.api.nvim_buf_get_lines(bufnr, 0, -1, false)
+  local content = table.concat(lines, "\n")
+
+  for _, opt in ipairs(opts) do
+    assert_truthy(
+      content:find(opt.option_text, 1, true),
+      "buffer should contain option " .. opt.option_number .. ": " .. opt.option_text
+    )
+  end
+
+  assert_truthy(content:find("Answer:", 1, true), "buffer should contain Answer: line")
+end)
+
+-- 46. Theory buffer: all options visible after replace import
+test("Theory buffer: options visible after replace import", function()
+  local importer = require("code-practice.importer")
+  local db_mod = require("code-practice.db")
+  local mgr = require("code-practice.manager")
+
+  local plugin_root = vim.fn.fnamemodify(debug.getinfo(1, "S").source:sub(2), ":h:h")
+  local fixture = plugin_root .. "/test/example_exercises.json"
+  local counts, err = importer.import(fixture, { replace = true })
+  assert_truthy(counts, "import returned nil: " .. tostring(err))
+
+  local theory = db_mod.get_all_exercises({ engine = "theory" })
+  if #theory == 0 then
+    skip("no theory exercises after import")
+  end
+
+  local failures = {}
+  for _, ex_row in ipairs(theory) do
+    local opts = db_mod.get_theory_options(ex_row.id)
+    if #opts == 0 then
+      table.insert(failures, string.format("exercise %d (%s): 0 options", ex_row.id, ex_row.title))
+    else
+      local bufnr = mgr.open_exercise(ex_row.id)
+      if bufnr then
+        local lines = vim.api.nvim_buf_get_lines(bufnr, 0, -1, false)
+        local content = table.concat(lines, "\n")
+        for _, opt in ipairs(opts) do
+          if not content:find(opt.option_text, 1, true) then
+            table.insert(
+              failures,
+              string.format("exercise %d option %d: %q not in buffer", ex_row.id, opt.option_number, opt.option_text)
+            )
+          end
+        end
+      end
+    end
+  end
+
+  if #failures > 0 then
+    error("Theory display failures:\n  " .. table.concat(failures, "\n  "))
+  end
+end)
+
+-- 47. manager.open_exercise content parity after bunload
+test("Manager: open_exercise content identical after bunload", function()
+  local mgr = require("code-practice.manager")
+
+  local buf1 = mgr.open_exercise(1)
+  assert_truthy(buf1, "first open nil")
+  local lines_before = vim.api.nvim_buf_get_lines(buf1, 0, -1, false)
+
+  mgr.open_exercise(2)
+  vim.cmd("bunload " .. buf1)
+
+  local buf1_again = mgr.open_exercise(1)
+  assert_truthy(buf1_again, "reopen nil")
+  local lines_after = vim.api.nvim_buf_get_lines(buf1_again, 0, -1, false)
+
+  assert_eq(#lines_before, #lines_after, "line count mismatch")
+  for i, line in ipairs(lines_before) do
+    assert_eq(line, lines_after[i], "line " .. i .. " differs")
+  end
+end)
+
+-- 48. manager.open_exercise focuses non-floating window
+test("Manager: open_exercise lands in non-floating window", function()
+  local mgr = require("code-practice.manager")
+
+  local buf = mgr.open_exercise(1)
+  assert_truthy(buf, "open nil")
+
+  local win = vim.api.nvim_get_current_win()
+  local ok_cfg, cfg = pcall(vim.api.nvim_win_get_config, win)
+  local is_floating = ok_cfg and cfg and cfg.relative and cfg.relative ~= ""
+  assert_eq(is_floating, false, "current window should not be floating after open_exercise")
+end)
+
+-- 49. popup.open_float with absolute sizes
+test("Popup: open_float respects absolute width/height", function()
+  local popup_mod = require("code-practice.popup")
+  local utils_mod = require("code-practice.utils")
+
+  local bufnr, winid = popup_mod.open_float({ width = 50, height = 20, title = " Abs Test " })
+  assert_truthy(bufnr, "bufnr nil")
+  assert_truthy(winid, "winid nil")
+
+  local win_width = vim.api.nvim_win_get_width(winid)
+  local win_height = vim.api.nvim_win_get_height(winid)
+  assert_eq(win_width, 50, "width")
+  assert_eq(win_height, 20, "height")
+
+  utils_mod.close_win(winid)
+end)
+
+-- 50. Results: hidden failing test must not leak its input/expected/actual
+test("Results: hidden failing test does not leak details", function()
+  local results = require("code-practice.results")
+
+  local result = {
+    passed = false,
+    results = {
+      { test_num = 1, passed = true, hidden = false, duration = 1, input = "[1]", expected = "1", actual = "1" },
+      {
+        test_num = 2,
+        passed = false,
+        hidden = true,
+        duration = 1,
+        input = "SECRET_INPUT",
+        expected = "SECRET_EXPECTED",
+        actual = "WRONG_ACTUAL",
+      },
+    },
+  }
+
+  results.show(result, nil)
+  local bufnr = results._bufnr
+  assert_truthy(bufnr, "results buffer nil")
+  local content = table.concat(vim.api.nvim_buf_get_lines(bufnr, 0, -1, false), "\n")
+  results.close()
+
+  -- The failed hidden test should still be listed as a failure...
+  assert_truthy(content:find("Test 2", 1, true), "hidden test should still appear as a result row")
+  -- ...but none of its internals may be revealed.
+  assert_truthy(not content:find("SECRET_INPUT", 1, true), "hidden test input leaked")
+  assert_truthy(not content:find("SECRET_EXPECTED", 1, true), "hidden test expected output leaked")
+  assert_truthy(not content:find("WRONG_ACTUAL", 1, true), "hidden test actual output leaked")
+end)
+
+-- 51. Help: browser cheat-sheet reflects configured keymaps
+test("Help: browser cheat-sheet reflects configured keymaps", function()
+  local config = require("code-practice.config")
+  local help = require("code-practice.help")
+  local utils = require("code-practice.utils")
+
+  local original = config.config.keymaps.browser
+  config.config.keymaps.browser = {
+    open_item = "<F6>",
+    filter_easy = "<F2>",
+    filter_medium = "<F3>",
+    filter_hard = "<F4>",
+    filter_all = "<F5>",
+    close = "<F7>",
+  }
+
+  local ok, err = pcall(function()
+    help.show()
+    local bufnr = vim.api.nvim_get_current_buf()
+    local winid = vim.api.nvim_get_current_win()
+    local content = table.concat(vim.api.nvim_buf_get_lines(bufnr, 0, -1, false), "\n")
+    utils.close_win(winid)
+
+    for _, key in ipairs({ "<F2>", "<F3>", "<F4>", "<F5>", "<F6>", "<F7>" }) do
+      assert_truthy(content:find(key, 1, true), "cheat-sheet missing configured browser key " .. key)
+    end
+  end)
+
+  config.config.keymaps.browser = original
+  if not ok then
+    error(err)
+  end
+end)
+
 -- Summary
 io.write("\n" .. string.rep("=", 44) .. "\n")
 io.write(string.format("  Results: %d passed, %d failed, %d skipped\n", passed, failed, skipped))