Improve Accessibility (Contrast, Font Size)

## Description
Enhance **accessibility** by improving color contrast and font sizes.

### Requirements
- Text should be readable on all backgrounds.
- Ensure headings, links, and buttons are clear.
- HTML & CSS only.

### File/Folder
- css/style.css
- components/* (update as needed)

### Example/Screenshot
- Optional screenshot showing improved readability.
