How do I get to a specific line of css without having to scroll through thousands of lines?

Use the Quick Edit panel (Ctrl + E).

Place cursor on a Tag, Class or ID in CODE view. 

Right-click and select Quick Edit.

This works best with embedded or attached stylesheets from your local site folder.  External stylesheets on CDNs can't be Quick Edited.

Hope that helps.

Mac: Cmd + ,

Win: Ctrl + g

Those will go to a specific line without having to know what's on that line.

You could try:

• Open the CSS document, hit CTRL+ F and enter a search term
• Open the page in a browser and go to the Devreloper Tools > Elements