fix: resolve blank landing screen due to hashed css module animations

[MohamedAli1937]

Description

This PR resolves an issue where the new Landing Screen was displaying as a blank black screen with blurry orbs, rather than showing the intended text and buttons.

The bug occurred because @keyframes (fadeUp, float1, float2) were defined inside a CSS Module (LandingScreen.module.css), which Vite automatically hashes. However, the LandingScreen.tsx component applies these animations via inline styles using hardcoded string names (e.g., animation: "fadeUp 0.6s..."), causing the animations to fail and leaving the content stuck at opacity: 0.

Changes:

• Removed keyframe definitions from LandingScreen.module.css.
• Moved the fadeUp, float1, and float2 keyframes to the global index.css stylesheet so they can be correctly targeted by the inline styles.

Fixes #325

Type of Change

• Bug fix
• New feature
• Breaking change
• Documentation update

How Has This Been Tested?

Verified that the animations now correctly execute and the landing screen fades in upon loading the app.

• Existing tests pass
• New tests added
• Manual testing

Screenshots (if applicable)

N/A

Checklist

• My code follows the project's style guidelines
• I have performed a self-review
• I have added/updated documentation as needed
• My changes generate no new warnings
• Tests pass locally