Why did my terminal's user@machine color change randomly?

I was following some direction for emacs and jshint install from here: Stanford startup course link

I initially ran into some trouble after launching emacs, where I began switching between tabs but I couldn't understand what was happening (I was "stuck" in one tab and couldn't get out of it). So I opened up a new Terminal window and connected back to the EC2 instance on AWS.

All of a sudden, instead of text being all yellow, the username@ip (e.g. ubuntu@XX.XXX.XXX) is showing up in purple, while the rest of the text is still yellow.

I have no idea if this is related, but after this, when I tried:

install npm install -g jshint

it gave me a bunch of error messages.

I've tried

sudo chown -R $(whoami) ~/.npm

in an attempt to change the ownership status of the npm folder but still I get the same errors.

When I open a new Terminal window, the color of text is yellow like normal but as soon as I connect to the EC2 instance, the [ubuntu@xx.xxx.xxx:~]$ becomes purple/blue again.

Can someone please help?