Put base.css into debug mode. See desc for instructions on using this with Chrome.

You can have the Chrome inspector display the line numbers in your SASS
files for easy debugging. It's incredible.

To get Chrome to use the debug info:
1. Go to chrome://flags and enable Developer Tools Experiments
2. Restart the browser
3. Open the web inspector and open the settings (the gear icon in the
lower right corner)
4. In the Experiments section, check 'Support for sass'.
5. In the General section, check 'Enable source maps'
6. Restart the browser again
7. Load a page that uses CSS with Sass debug info
8. See the sass file line numbers in the web inspector