Rounded Box (Well, really a half box)

Half box written in openscad code. Rounded edges and corners for human interface. Variables are available in the first few lines as follows:
xsize=length
ysize=width
zsize=height
thick=thickness of sides
roundc=radii of corners and edges
fn_edge_out=edge outside # of segments
fn_edge_in=edge inside # of segments
fn_corner_out=corner outside # of segments
fn_corner_in=corner inside # of segments

All dimensions are in mm.
Fn values are the number of segments in rounded edges and corners. Large values increase smoothness of these elements, but slow rendering. Recommend using fn values shown to start your design.
I make no guarantees for extreme values of variables, so use at own risk.