[BUG]: Improve hover state contrast ratio of download buttons to meet WCAG AA standards

### Bug Description

## Problem

On the PictoPy landing page, the hover state of the download buttons (Windows, Linux) shows insufficient background-to-text contrast.

## Accessibility Concern

According to WCAG 2.1 AA standards:

Normal text requires a contrast ratio of at least 4.5:1

Large text requires at least 3:1

The current hover states appear to fall below the required threshold.

## Expected Behavior

Hover states should:

Maintain a minimum 4.5:1 contrast ratio

Preserve visual consistency

Remain distinguishable from default state

### Steps to Reproduce

1. Open the PictoPy website.

2. Navigate to the landing section with the Download buttons.

3. Hover over the Download for Windows button.

4. Inspect the button using Chrome DevTools - Color Picker.

5. Observe the reported contrast ratio between text and background in hover state.

### Logs and Screenshots

### Code of Conduct

- [x] I have joined the [Discord server](https://discord.gg/hjUhu33uAn) and will post updates there
- [x] I have searched existing issues to avoid duplicates