My standard config.rb for compass

config.rb

# Require any additional compass plugins here.

# Set this to the root of your project when deployed:
http_path = "/"
css_dir = "css"
sass_dir = "sass"
images_dir = "img"
javascripts_dir = "js"

# You can select your preferred output style
# here (can be overridden via the command line):
# output_style = :expanded or :nested or :compact or :compressed

output_style = :nested

# To enable relative paths to assets via
# compass helper functions. Uncomment:
# relative_assets = true

# To disable debugging comments that display the
# original location of your selectors. Uncomment:
# line_comments = false

# Comment this out to default to SCSS:
# preferred_syntax = :sass

sourcemap = true
Sass::Script::Number.precision = 8