If you look closely at the prettified key sequences—like this 【Meta+x】 one—you will notice that they now have slightly rounded corners in the hopes that they will be a tiny bit more suggestive of actual keys. I did that by using the border-radius property in CSS3. All I did was to add the line
border-radius: 3px;
to the .key definition. I didn’t add any of the browser specific border-radius properties.
Despite the title, I’m really a CSS noob, so if things don’t look right to you or the keys don’t look rounder and you are using a modern browser, please leave a comment.