Gradient changing background added

[shreya-paul-17]

Description

The todo cards are changed wrt the gradient color background which will change with the help of animation effects added to it

Fixes #207

Type of change

Please delete options that are not relevant.

• New feature (non-breaking change)

How Has This Been Tested?

Please describe the tests that you ran to verify your changes. Provide instructions so that they can be reproduced.

• Test A

I have opened the live server in my IDE and checked whether it was getting applied to all the todo cards or not.
And, it has run successfully ap per the requirements.

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my code
• My changes generate no new warnings

Kindly review my PR and add the hacktoberfest-accepted label to it @Anshgrover23

[Anshgrover23]

@shreya-paul-17 kindly attach screenshot of before and after.

[shreya-paul-17]

Screenshot (Before):

Screenshot (After):

I have added screenshots as per your instructions. Please check @Anshgrover23 and add hacktoberfest-accepted label after merging it to the base repo

[Anshgrover23]

@shreya-paul-17 poor work.