To add professional form handling with css

[NithinU2802]

Hi, as per the goal of this repository, I would like to contribute by adding a professional fully functional form that handles validation, error messaging, and success feedback using only CSS.

Implement a signup form that includes:

• Input validation for fields like name, email, phone, and password using HTML5 validation and CSS pseudo-classes.
• Error messages that appear only after the user interacts with a field (not before typing).
• Disabled submit button when the form is invalid.
• Success popup/modal shown after successful submission, using only CSS (e.g., with the :target selector).
• Responsive and professional design using modern CSS (custom fonts, gradients, spacing, etc.).
• No JavaScript at all—all interactivity and feedback are handled with HTML and CSS only.

Please refer the below screenshots and I'm happy to get assigned and raise a PR accordingly🚀.

[aayush105]

Hello @NithinU2802
I have assigned it to you.