WYSIWYG content editor for the World Wide Web. Powered by Gecko, the rendering engine of Firefox 4, it is the next generation from Kompozer. It's free to download (current stable version is 1.4) and is available on Windows, Mac OS X and Linux, funded via 'buy in' modules for extra functionality.

The core of Foundation can be summed up in a few points: A 12-column, percentage-based grid with an arbitrary maximum width. The grid can be nested and used for quite complex layouts, and it works all the way back to IE 7. The grid reshuffles itself for smaller devices. Image styles that disregard pixels. Images in Foundation are scaled by the grid to different widths. UI and layout elements. Foundation includes common pieces such as typography and forms, as well as tabs, pagination, N-up grids and more. Mobile visibility classes. Rapidly prototyping is partly about having built-in functionality to tailor the experience. Foundation lets you very quickly hide and show elements on desktops, tablets and phones. We deliberately built Foundation as a starting point, not as a style guide. We've included some styles to help you rapidly build something clickable and usable, but not something stylistically complete. Everything in Foundation is meant to be customized, including button styles, form styles (even custom radio, checkbox and select elements), typography, and layout elements such as tabs.