When you're templating and routing it's helpful to see html elements labeled and and visible even if they're empty while still being able to interact with the webpage. Dev.css does exactly that, as well as displays the current ids and classes assigned to each element. Add it to your <head> like this:
<link rel="stylesheet" type="text/css" href="https://cdn.jsdelivr.net/gh/JSlote/dev.css@master/dev.css">