We did something similar to this, but used ~ instead, like so: ~ Definition title The definition data should be indented at the same level as the tit

We did something similar to this, but used ~ instead, like so: ~ Definition title The definition data should be indented at the same level as the title. This let's you nest definitions also: ~ Like this Here's a nested definition. We also allowed : instead of ~ but most people seemed to prefer the latter. We didn't collapse anything in rendering though, but it's not a bad idea. The resulting markup when rendered to HTML was actual definition lists (<dl>) though, not details, so that'd either have to be done by nesting details or css magic I suppose.