Gridlock
Lay a column grid over any site
Set columns, gutter, and margin once, then toggle the overlay on any page to check what lines up and what drifts.
Chrome
This is a Chrome extension. A store listing is on the way. Until then you can load the unpacked folder from the project, or write to me if you want a note when it is live.
Privacy
Work stays on your device. There is no analytics. See the privacy policy for what each permission is for.