[![ IMAGE OF THE WEB PAGE I WANT TO CREATE, I CREATED THAT IMAGE IN PAINT!](https://i.stack.imgur.com/wI0j4.png)](https://i.stack.imgur.com/wI0j4.png)

I want to create a web page which takes a number as input then Even or ODD background color changes depending upon the number for eg if I enter 2 then Odd background color becomes gray and even background color becomes Green, I hope u understand what I want to do, the thing is I want to place the input field in the middle like in the picture, Can anyone help me how to do that? it would be very helpful for future purposes also, Thank you!!!!