Tor2web injected banner should exploit CSS3 all shorthand property and of the the unset keyword

[evilaliv3]

CSS Cascading and Inheritance Level 3 introduces the all shorthand property and the unset keyword, which, together, allow you to achieve this conveniently.

http://www.w3.org/TR/css3-cascade/#all-shorthand

For example, if an author specifies all: initial on an element it will block all inheritance and reset all properties, as if no rules appeared in the author, user, or user-agent levels of the cascade.

This is in general useful for widgets and would be useful for the banner in order to make sure that on CSS3 browser it will always look as we want without being overridden by the onion css files.

what we would need is to apply:

#tor2web * {
  all: unset; /* allowing inheritance within #mydiv */
}

To be really safe, we may want to block styles on potential pseudo-element descendants too:

#tor2web::before,
#tor2web::after,
#tor2web *::before,
#tor2web *::after {
  all: unset;
}

[evilaliv3]

i gived a try but i don't find it working properly. let's postpone its analyisis unt we probably would end in the iframe impleementation that would offer more guarantees