The left-most (100%) rectangle should be indistinguishable from the black background. Try turning up your "contrast" if some others are disappearing. If some other blocks blend together here and there, you may want to:
Any browser will work fine for the most part, but will not show specified fonts and other page design features.
Among the dominant browsers, those that currently support
CSS include Microsoft Internet Explorer 3.0 and above, Netscape Navigator 4.0 (Communicator) and above.
Many others also support this advancement, and the very latest versions coming out often have great improvements in this regard.