diff --git a/Makefile b/Makefile
index 6b6158b..4dbd615 100644
--- a/Makefile
+++ b/Makefile
@@ -6,7 +6,7 @@ build   := uv build
 publish := uv publish --username=__token__ --keyring-provider=subprocess
 python  := $(run) python
 ruff    := $(run) ruff
-lint    := $(ruff) check --select I
+lint    := $(ruff) check
 fmt     := $(ruff) format
 mypy    := $(run) mypy
 spell   := $(run) codespell
diff --git a/pyproject.toml b/pyproject.toml
index e587702..26cb259 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -95,3 +95,26 @@ explicit = true
 venvPath="."
 venv=".venv"
 exclude=[".venv"]
+
+[tool.ruff.lint]
+select = [
+    # pycodestyle
+    "E",
+    # Pyflakes
+    "F",
+    # pyupgrade
+    "UP",
+    # flake8-bugbear
+    "B",
+    # flake8-simplify
+    "SIM",
+    # isort
+    "I",
+]
+ignore = [
+    # I think try...expect...pass reads far better.
+    "SIM105",
+]
+
+[tool.ruff.lint.pycodestyle]
+max-line-length = 120
diff --git a/src/aging/data/config.py b/src/aging/data/config.py
index cb6b999..9402357 100644
--- a/src/aging/data/config.py
+++ b/src/aging/data/config.py
@@ -2,12 +2,12 @@
 
 ##############################################################################
 # Python imports.
+from collections.abc import Iterator
 from contextlib import contextmanager
 from dataclasses import asdict, dataclass, field
-from functools import lru_cache
+from functools import cache
 from json import dumps, loads
 from pathlib import Path
-from typing import Iterator
 
 ##############################################################################
 # Local imports.
@@ -84,7 +84,7 @@ def save_configuration(configuration: Configuration) -> Configuration:
 
 
 ##############################################################################
-@lru_cache(maxsize=None)
+@cache
 def load_configuration() -> Configuration:
     """Load the configuration.
 
diff --git a/src/aging/screens/main.py b/src/aging/screens/main.py
index 34b3a9d..53e5334 100644
--- a/src/aging/screens/main.py
+++ b/src/aging/screens/main.py
@@ -3,8 +3,8 @@
 ##############################################################################
 # Python imports.
 from argparse import Namespace
+from collections.abc import Iterator
 from pathlib import Path
-from typing import Iterator
 
 ##############################################################################
 # NGDB imports.
@@ -396,7 +396,7 @@ def _open_guide(self, message: OpenGuide) -> None:
         # actually is a guide.
         try:
             new_guide = NortonGuide(message.location)
-        except IOError as error:
+        except OSError as error:
             self.notify(
                 str(error), title=f"Error opening {message.location}", severity="error"
             )
diff --git a/src/aging/screens/search.py b/src/aging/screens/search.py
index 4998d33..ff0434f 100644
--- a/src/aging/screens/search.py
+++ b/src/aging/screens/search.py
@@ -1,9 +1,10 @@
 """Provides the search screen."""
 
 ##############################################################################
-# NGDB imports.
+# Python imports.
+from collections.abc import Iterator
 from dataclasses import dataclass
-from typing import Iterator, NamedTuple
+from typing import NamedTuple
 
 ##############################################################################
 # Humanize imports.
@@ -525,7 +526,7 @@ def _search_guide(
                         return
                     self._search_entry(search, entry, worker, needle, ignore_case)
             self.post_message(self.FinishedGuide())
-        except (IOError, NGDBError) as error:
+        except (OSError, NGDBError) as error:
             self.notify(
                 str(error), title=f"Failed to search {guide.location}", severity="error"
             )
diff --git a/src/aging/widgets/entry_viewer/entry_content.py b/src/aging/widgets/entry_viewer/entry_content.py
index e7d9e9f..3bf88f7 100644
--- a/src/aging/widgets/entry_viewer/entry_content.py
+++ b/src/aging/widgets/entry_viewer/entry_content.py
@@ -313,34 +313,35 @@ def render_line(self, y: int) -> Strip:
             option_index, _ = self._lines[self.scroll_offset.y + y]
         except IndexError:
             return strip
-        if option_index == self.highlighted:
-            if highlight := self.get_visual_style("option-list--option-highlighted"):
-                highlight_style = highlight.rich_style
-                # Despite its name, Style.without_color removes more than
-                # colour; one of the things it removes it `meta`. The
-                # OptionList uses meta to know which option was clicked on.
-                # So we need to peek into the highlight strip and pull out
-                # an example of the style so we can get the meta for later.
-                borrowed_style = next(iter(strip)).style
-                strip = Strip(
-                    [
-                        Segment(
-                            text,
-                            style.without_color + highlight_style
-                            if style is not None
-                            else None,
-                            control,
-                        )
-                        for text, style, control in strip
-                    ]
-                ).simplify()
-                # So here, if we have a borrowed style, and if it has meta
-                # information, we apply it to the new strip we created so
-                # that the `option` value is retained. Without it the user
-                # wouldn't be able to cause an `OptionSelected` message from
-                # clicking on a highlighted option.
-                if borrowed_style is not None and borrowed_style.meta:
-                    strip = strip.apply_meta(borrowed_style.meta)
+        if option_index == self.highlighted and (
+            highlight := self.get_visual_style("option-list--option-highlighted")
+        ):
+            highlight_style = highlight.rich_style
+            # Despite its name, Style.without_color removes more than
+            # colour; one of the things it removes it `meta`. The
+            # OptionList uses meta to know which option was clicked on.
+            # So we need to peek into the highlight strip and pull out
+            # an example of the style so we can get the meta for later.
+            borrowed_style = next(iter(strip)).style
+            strip = Strip(
+                [
+                    Segment(
+                        text,
+                        style.without_color + highlight_style
+                        if style is not None
+                        else None,
+                        control,
+                    )
+                    for text, style, control in strip
+                ]
+            ).simplify()
+            # So here, if we have a borrowed style, and if it has meta
+            # information, we apply it to the new strip we created so
+            # that the `option` value is retained. Without it the user
+            # wouldn't be able to cause an `OptionSelected` message from
+            # clicking on a highlighted option.
+            if borrowed_style is not None and borrowed_style.meta:
+                strip = strip.apply_meta(borrowed_style.meta)
         return strip
 
     def search_next(self) -> None:
diff --git a/src/aging/widgets/guide_directory.py b/src/aging/widgets/guide_directory.py
index 466f40c..241beac 100644
--- a/src/aging/widgets/guide_directory.py
+++ b/src/aging/widgets/guide_directory.py
@@ -12,7 +12,6 @@
 ##############################################################################
 # Textual imports.
 from textual import on, work
-from textual.binding import Binding
 from textual.reactive import var
 from textual.widgets.option_list import Option, OptionDoesNotExist
 
@@ -193,7 +192,7 @@ def _refresh_guides(self, new_guides: Guides) -> None:
         """
         try:
             save_guides(new_guides)
-        except IOError as error:
+        except OSError as error:
             self.notify(str(error), title="Unable to save guides", severity="error")
             return
         self.post_message(GuidesUpdated())