Improve semantic HTML and responsiveness

[raphaelalmeidamartins]

Congratulations on your project! :cat2:

I made a few improvements:

• [x] Replaced divs with the correct semantic HTML tags
• [x] Refactored some parts of your code to make it more readable and cleaner
• [x] Fixed some responsiveness issues
• [x] Added my two cats to your db
• [x] Added json syntax highlight to the README

Here is my Linkedin profile. Let's collaborate more :rocket: