We have a lot of browsers poping up every year. Not to mention the versions they come in. At times it can prove difficult to check if the website you have designed would look good in all browser. Browser compatibility has always been a web designers nightmare. Taking into account of this, i thought it would be useful to have a look at the various selectors and declarations used in the CSS 2.1 and CSS 3.
I would suggest you stick to CSS 2.1 as of now and use the advanced selectors judiciously based on your client browsers.
Let us check the compatibility charts of CSS and the popular browsers in the market. Most of the other browsers you get to see in the net will be using one of the layout engines used by the browsers in chart. Hence i feel the chart would suffice the needs of browser compatibility factor for your site.