It also lacks basic HTML4.01 support, such as for HTML4.01 tables (currently only supports HTML3.2 tables), support for basic <object> tag attributes, <a> attributes coords and shape, and a few other key elements.
Opera 5 supports all of CSS2 with the exception of:
Opera 5 is a visual browser and does not support Aural CSS
these properties: clip, cursor, direction, font-size-adjust, font-stretch, marker-offset, marks, text-shadow, unicode-bidi, and all outline properties
the system values on the font property as well as system colors (before 5.10/Windows and all non-Windows platforms)
the values added to list-style-type in CSS2
these property/value combination: 'display: marker', 'text-align: <string>', 'visibility: collapse', 'content: <url>', 'overflow: scroll', 'overflow:auto'
named pages (as described in section 13.3.2)
the '@font-face' construct
All CSS2 selectors are supported with the exception of:
:first-child, :focus, :lang
combinations with pseudo-classes before other selectors