This patch fixes a rendering bug in fbpdf.c where inverted colors were only applied correctly in the full redraw path, but not consistently when pages were loaded incrementally during multipage navigation. The inversion logic now runs at the point each page buffer is created, covering forward, backward, and initial loads with the same behavior. That keeps the display mode consistent as pages are reused and redrawn, so inverted viewing now works reliably across multipage browsing.