Problems with html5 mark tags in Opera

I was testing my website when I found a rendering problem in Opera 11.11 when using the <mark> tag inside a text block.

As you can see in the picture, <mark> is not inline and break the text color. As new user, I can't embed image, so I link it: http://i.开发者_JAVA技巧stack.imgur.com/4w8ga.png

Here is the page I use for testing: http://trybooksharing.altervista.org/tests/mark-test.html

Is that problem known? Is there any solution, css workaround, or similar?

Thank for help!

This is a known issue. It had a bug at Opera (CORE-39086) and has been fixed. It will be integrated in a future release. I don't know yet when exactly. There is no CSS Work around to the best of my knowledge.