25. Visual effects

overflow

Determines what to do if content of a block box overflows its edges.

visible (the default)

Overflowed content is visible outside the box.

hidden

Overflowed content (if any) is clipped.

scroll

A scrolling mechansim allows overflowed content to be viewed.

auto

Browser-dependent; optional scrolling.

visibility

visible (the default)

The box is visible.

hidden

The box is invisible (transparent), but still affects layout.

collapse

On table rows and columns only: remove the row or column from display.

z-index: integer

controls the stacking order of positioned elements, i.e., which element is highest when two or more elements overlap.