Opera and IE CSS3 logo
Pure CSS3 browser logos. These logos are created using basic CSS3 shapes and properties like linear-gradient, box-shadow, border-radius, etc. Although, these don't look exacty like the original logos but it's still a nice try. You can view a much better example of Opera logo created in CSS3 here and Internet Explorer logo here.
These logos won't look good in Internet Explorer 8 and below as it lacks the support of CSS3. Also, take a look at the source code of these logos to learn more about the creation process of them.