Starting with Spark Laravel

I'm trying Spark and, after install it, I have two problems:

1.- When I try 'Log in' and 'Register' buttons, I get this. It is like if my web page with no style. Any idea what I am doing wrong?

2.- On the other hand, I'm following the Quickstart guide and I'm trying this:

"Once Spark is installed, make sure the NPM dependencies have been installed via the npm install command, the gulp command has been executed, and the database migrations have ran."

I'm running npm install in my Terminal and I'm getting this: -bash: npm: command not found.

I did some things with Laravel more than one year ago, and it was with no Homestead. Probably I'm doing something wrong... I'm pretty confusing.

Any help would be really appreciated! :)

via Chebli Mohamed