## Coordinate systems in GTK
-Every widget in a window has its own coordinate system that it uses to place its
-child widgets and to interpret events. Most of the time, this fact can be safely
-ignored. The section will explain the details for the few cases when it is important.
-
All coordinate systems in GTK have the origin at the top left, with the X axis
pointing right, and the Y axis pointing down. This matches the convention used
in X11, Wayland and cairo, but differs from OpenGL and PostScript, where the origin
is in the lower left, and the Y axis is pointin up.
+Every widget in a window has its own coordinate system that it uses to place its
+child widgets and to interpret events. Most of the time, this fact can be safely
+ignored. The section will explain the details for the few cases when it is important.
+
## The box model
When it comes to rendering, GTK follows the CSS box model as far as practical.