Change background color of single page NOT WORKING.

I have put in the code in the settings > advanced and saved.

<style> .Main {background-color: #000000 !important; } </style>

but the page still appears the same.

also tried using collections in css - #collection-657167bc475a9a5366cdf001 { background-color: #000000 !important; }

im trying to change this page https://groundhog-cow-f7s6.squarespace.com/about 

pw: hi 

Your code target class name in 7.0 version, but your site is 7.1 version

Use this code to Settings > Advanced

<style>
  section, .section-border, .section-background {
  	background-color: #000 !important;
  }
</style>