UI refinements (#2859)

## Description:

UI Refinements requested by @evanpelle  check https://ui.openfront.dev

## Please complete the following:

- [x] I have added screenshots for all UI updates
- [x] I process any text displayed to the user through translateText()
and I've added it to the en.json file
- [x] I have added relevant tests to the test directory
- [x] I confirm I have thoroughly tested these changes and take full
responsibility for any bugs introduced

## Please put your Discord username so you can be contacted if a bug or
regression is found:

w.o.n

src/client/styles/components/modal.css

@@ -1,13 +0,0 @@
-/* Deprecated global modal styles.
-   The component-scoped styles in src/client/components/baseComponents/Modal.ts
-   are the single source of truth now. Removing global overrides so the
-   component can control layout and internal scrolling behavior. */
-
-/* Keep small helper rule for legacy button layout, remove global .c-modal rules */
-o-modal o-button {
-  @media (min-width: 1024px) {
-    margin: 0 auto;
-    display: block;
-    text-align: center;
-  }
-}