Remove dropdown text customization from sphinx-exercise CSS

- Dropdown button text styling is better handled at theme level
- Removes CSS override for toggle-button text from exercise.css
- Updates documentation to suggest theme-level customization
- Updates CHANGELOG to reflect architectural decision

Author: mmcky

CHANGELOG.md

@@ -7,13 +7,18 @@
 - Added `exercise_style` configuration option to control solution title styling
   - Set to `"solution_follow_exercise"` to remove hyperlinks from solution titles when solutions follow exercises directly
   - Default is `""` (empty string) which maintains the original clickable hyperlink behavior
-- Changed dropdown button text from "Click to show" to "Show" (and "Click to hide" to "Hide") for cleaner visual appearance
 
 ### Improved 👌
 
 - Enhanced solution title styling options for better UX in lecture-style content where solutions follow exercises
 - Improved configuration option naming for better clarity when used alongside other Sphinx extensions
 
+### Changed 🔄
+
+- Removed dropdown button text customization from `sphinx-exercise` CSS
+  - This styling is better handled at the theme level (e.g., in `quantecon-book-theme`) for consistent global behavior
+  - Projects can customize dropdown text in their theme or custom CSS if desired
+
 ## [v1.1.1](https://github.com/executablebooks/sphinx-exercise/tree/v1.1.1) (2025-10-23)
 
 ### Improved 👌

docs/source/syntax.md

@@ -343,10 +343,12 @@ sphinx:
 
 To hide the content, simply add `:class: dropdown` as a directive option.
 
-**Note:** The dropdown toggle button text has been customized for `sphinx-exercise` directives to display "Show" / "Hide" instead of the default "Click to show" / "Click to hide" for a cleaner visual appearance.
-
 For more use cases see [sphinx-togglebutton](https://sphinx-togglebutton.readthedocs.io/en/latest/#usage).
 
+```{tip}
+To customize the dropdown toggle button text (e.g., "Show" instead of "Click to show"), add custom CSS in your theme or project. This is typically handled at the theme level for consistent styling across all toggle buttons.
+```
+
 **Example**
 
 ```{exercise}

sphinx_exercise/assets/html/exercise.css

@@ -41,17 +41,3 @@ div.solution p.admonition-title {
 div.solution p.admonition-title::after {
   content: none;
 }
-
-/*********************************************
-* Dropdown customization *
-*********************************************/
-/* Change "Click to show" to "Show" for dropdowns */
-div.exercise.dropdown button.toggle-button::before,
-div.solution.dropdown button.toggle-button::before {
-  content: "Show";
-}
-
-div.exercise.dropdown.toggle-shown button.toggle-button::before,
-div.solution.dropdown.toggle-shown button.toggle-button::before {
-  content: "Hide";
-}