Exclude Blog Post Pages from Custom CSS

Hi,

Thanks in advance for your help.

I have custom code injected on my site so that the header for each site page is different on desktop and mobile. 

The problem is that I would like to start posting blog content, and the code I used is making it so that the blog post content isn't visible on mobile devices. 

The site url is https://poze.app

The code I used is: 

<style>
@media only screen and (max-width: 780px) {
    #page section:nth-of-type(1) { 
            display: none; 
    } 
  }
@media only screen and (min-width: 781px) {  
    #page section:nth-of-type(2) { 
        display: none !important;
    }
  }
   @media only screen and (min-width: 781px) {  
    #page section:nth-of-type(3) { 
        display: none !important;
    }
  }

Is it possible to exempt all blog post pages from this code injection? 

Thanks.