Jade indentation and spaces simple

Jade indentation and spaces simple

Im starting to learn Jade and I use Sublime Text 2 as my editor.
This code:
extends layout
block content
h1= title
p Welcome to #{title}
ul.new_class
li Hello
li#id Goodby
Gives me the error:
500 Error:
/Users/jrdillon522/Desktop/Coding-Dojo/node/express/helloExpress/views/index.jade:7
5| p Welcome to #{title} 6| ul.new_class > 7| li Hello 8| li#id Goodby 9|
Invalid indentation, you can use tabs or spaces but not both
I'm not sure why because I never hit the space bar. Only tabs.