removed footer on all of my pages.

I tried to remove my footer on one page using a code block with code 

<style>
  /* remove footer */
  footer.sections {display: none;}
</style>

then I noticed that there was no footer on any of the other pages. I couldn't recover the footer section since it was completely gone so I removed that page to see if that would reset things on other pages. but it did not. Can someone tell me how to get my footer back, please. I would greatly appreciate it. 

Yes I was able to remove that code inside safe mode. thank you so much.

I thought it would just remove the footer from that one page since I was putting in the footer id from that particular page but what I notices is that unlike the header the footer id is the same in all of the pages. Is there a workaround for that. Has anyone removed a footer from just one page using code? 

You can restrict an effect to a particular page by adding the collection id to your CSS.