Window or door having a modular sill system

A window or a door comprising:

• a fixed frame and a leaf, wherein the leaf is movable transversely to the main plane of the fixed frame from a latching position into a sliding position and back into the latching position and can be slid parallel to the main plane of the frame in the sliding position;
• wherein the fixed frame has a vertically running first sealing plane and a vertically running second sealing plane, wherein the first sealing plane is horizontally offset from the second sealing plane, wherein the leaf is sealed in the latching position in the sealing planes by bearing against the fixed frame;
• wherein the fixed frame has a sill;
• wherein the sill has a main profile extending horizontally in or horizontally parallel to the main plane of the frame and an intermediate profile arranged on the main profile and extending horizontally in or horizontally parallel to the main plane of the frame;
• and
• wherein the intermediate profile has a first bearing portion for the leaf in the first sealing plane.