✨ Feature: Dynamic Accent Themes + Glassmorphic Dashboard Upgrade

Description:

This issue proposes enhancing the To-Do-List UI with a modern, interactive, and theme-based experience. The goal is to provide users with a sleek, glassmorphic interface and customizable gradient color themes for better personalization and visual appeal.

🧵 Linked Pull Request

This issue addresses PR: #391

🔧 Enhancements Added

🌈 Dynamic Accent Colors:
Users can now pick from 6 premium gradient-based color themes.

💎 Glassmorphism Header & Footer:
Transparent frosted panels with subtle blur for a modern aesthetic.

🎨 Full-Page Gradient Backgrounds:
Each theme features a unique 3-color gradient palette.

🪞 Smooth Theme Transitions:
Seamless 0.5s color fade when switching between themes.

🧊 Fixed Background Attachment:
Background stays static while scrolling for a premium effect.

🏁 Status

✅ Feature completed and ready for review under Hacktoberfest 2025.

🎉 Submitted as part of Hacktoberfest 2025 by [@JwelSrivastava](https://github.com/JwelSrivastava)