An extension for designers and developers who care about vertical rhythm. This tool will add a grid layer on top of any website to be used as a guidance when developing interfaces. You can set the horizontal guides to match your specification as well as the starting point, in case you're only concerned about individual modules of your site. For better experience, you can change the colour of the lines as well as the opacity, making it easier to compare the grid with your website design. As of v5.3, the configuration you set for each URL is saved on localStorage, so you can go back later on and keep the grid as it was last time. Developed by J. Pedro Ribeiro (@jpedroribeiro), Designed by Tim Davey (@TJDaveyUK), and constantly updated with support of the open source community.