send button colour problem in IE9

Hi,
I changed the style of the send button like in this post: http://pedromatias.co.uk/how-to-style-the-contact-form-7-submit-button/#comment-816563093

But in IE9 the color do not show up. I used:
‘background:#05A1F5 ! important;’

Any idea?

http://ww.wp.xz.cn/extend/plugins/contact-form-7/