I'd like to share this small HTML/CSS file as for anyone interested in quickly making a layout for keyboard buttons and mouse clicks with just CSS. I use it as help overlay for all my custom buttons on Windows. (I keep forgetting some).
It's very easy and self-explanatory to adjust the HTML only and get what you need. There is a bit of jquery to make it easier, but still semantic right.
It's also designed for Firefox without checking other browsers since I only use it to make a screenshot from it and the display it as a help splashimage in autohotkey.