Google Custom Search in Header

It took me a long time to get this how I wanted it, so I figured I'd post instructions here in case anyone was trying to do the same thing.

What I wanted was a small Google Custom Search bar in my header that would fit there without displacing my logo on any common display type (phone, tablet, desktop). I wanted this to supplement XenForo's search, not to replace it.

Please note that my settings are designed to work well with an 80px wide by 65px high small logo. If you use a bigger logo, you'll need to adjust the settings.