Use white or transparent PLA so LEDs can shine through the thin layer in middle.

(Things needed)

2 sheets of acrylic 280mm x 120mm.

Mirror window film

3M 9448A adhesive tape

LED Strip 10mm wide

(Directions) 

1) Cut acrylic to size and sand edges.

2) Apply window film to acrylic.

3) stick LED strip in channel of printed frame, wire out hole in back.

4) Use adhesive tape to attach acrylic (Film side to frame).

5) Done.