Here is what's going on: you add the text-white to the wrapper so all text is white and the default background color is white too so the page will look like it's empty.

also the bg [#1520b] the value here is invalid it should be 3 or 6 letters long and you should connect it with bg using - like this bg-[#1520b9], but it won't work either because you can't use arbitrary values in tailwind with react like this. so I would recommend that you move it to inline style like this:

style={{backgroundColor:'#1520bf'}}

and the same goes for max-w-[1400px] make it :

style={{maxWidth:'1400px'}}

So your code should look like this:

    import { constants } from 'buffer'
    import type { NextPage } from 'next'
    import Head from 'next/head'
    import Image from 'next/image'

    const style = {
          wrapper: 'flex justify-center h-screen w-screen select-none  text-white',
          content: ' w-2/3 flex justify-between',
         }


export default function Home(){
  return (
  <div className = {style.wrapper} style={{backgroundColor:'#1520bf'}}>
    <div className = {style.content} style={{maxWidth:'1400px'}}>
      <h2>Sidebar</h2>
      <h2>Feed</h2>
      <h2>Widgets</h2>
   </div>  
   </div>  
  )
}