title: CSS - adjust container width
body: <p>I'm making a few changes to a site and want to change the width of the container to go across the whole page. I'm a bit of a noob so not sure if I've don't it correctly, but want the width to be 3000px. I have the option of container id and container class. So basically what CSS do I put in which box?
  The theme  I am using is Porto by Spyropress. But looking for some CSS help:) 
  Thank you very much!!</p>