Add cosmic login page

[spy-in-shadows]

Description

🌌 Cosmic Login Page

A modern, responsive login page with a glowing cosmic gradient background and floating label inputs.

✨ Features

• Responsive design
• Smooth input animations
• Glassmorphism effect
• Gradient background
• Hover transitions on the login button

🧠 Tech Used

• HTML5
• CSS3 (Flexbox, gradients, transitions)

Checklist

• I've been assigned an issue related to this PR.
• I've used beautifiers.
• I've added my Project's name and description to Index.md
• I've made a README.md file for my Project.
• The README.md file of my projrct contains Project title, Description, Use of project, Set up, Stack used and Output (Screenshots).

Related Issues or Pull Requests number

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