Relationships would be awesome: .col1 { height: {col2.height}; } Basically what people do with JavaScript, but built-in. Implementation-wise, I don'

Relationships would be awesome: .col1 { height: {col2.height}; } Basically what people do with JavaScript, but built-in. Implementation-wise, I don't think it would be very difficult to make two block-level elements abide by each other's box model (determine height of .col1 as if it were .col2's parent). This would have very good consequences for user-customizable pages as well.