api (#4892)

# Description of Changes

<img width="1253" height="816" alt="image"
src="https://github.com/user-attachments/assets/51154a0e-4353-4e62-83c5-0896bc4e98df"
/>


---

## Checklist

### General

- [ ] I have read the [Contribution
Guidelines](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/CONTRIBUTING.md)
- [ ] I have read the [Stirling-PDF Developer
Guide](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/devGuide/DeveloperGuide.md)
(if applicable)
- [ ] I have read the [How to add new languages to
Stirling-PDF](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/devGuide/HowToAddNewLanguage.md)
(if applicable)
- [ ] I have performed a self-review of my own code
- [ ] My changes generate no new warnings

### Documentation

- [ ] I have updated relevant docs on [Stirling-PDF's doc
repo](https://github.com/Stirling-Tools/Stirling-Tools.github.io/blob/main/docs/)
(if functionality has heavily changed)
- [ ] I have read the section [Add New Translation
Tags](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/devGuide/HowToAddNewLanguage.md#add-new-translation-tags)
(for new translation tags only)

### Translations (if applicable)

- [ ] I ran
[`scripts/counter_translation.py`](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/docs/counter_translation.md)

### UI Changes (if applicable)

- [ ] Screenshots or videos demonstrating the UI changes are attached
(e.g., as comments or direct attachments in the PR)

### Testing (if applicable)

- [ ] I have tested my changes locally. Refer to the [Testing
Guide](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/devGuide/DeveloperGuide.md#6-testing)
for more details.

frontend/src/core/styles/theme.css

@@ -279,6 +279,15 @@
   --modal-content-bg: #ffffff;
   --modal-header-border: rgba(0, 0, 0, 0.06);
 
+  /* API Keys section colors (light mode) */
+  --api-keys-card-bg: #ffffff;
+  --api-keys-card-border: #e0e0e0;
+  --api-keys-card-shadow: rgba(0, 0, 0, 0.06);
+  --api-keys-input-bg: #f8f8f8;
+  --api-keys-input-border: #e0e0e0;
+  --api-keys-button-bg: #f5f5f5;
+  --api-keys-button-color: #333333;
+
   /* PDF Report Colors (always light) */
   --pdf-light-header-bg: 239 246 255;
   --pdf-light-accent: 59 130 246;
@@ -539,6 +548,15 @@
   --modal-content-bg: #2A2F36;
   --modal-header-border: rgba(255, 255, 255, 0.08);
 
+  /* API Keys section colors (dark mode) */
+  --api-keys-card-bg: #2A2F36;
+  --api-keys-card-border: #3A4047;
+  --api-keys-card-shadow: none;
+  --api-keys-input-bg: #1F2329;
+  --api-keys-input-border: #3A4047;
+  --api-keys-button-bg: #3A4047;
+  --api-keys-button-color: #D0D6DC;
+  
   /* Code token colors (dark mode - Cursor-like) */
   --code-kw-color: #C792EA;   /* purple */
   --code-str-color: #C3E88D;  /* green */