Browser compatibility is a crucial concern in the field of website development. In order to make sure your website performs well on all browsers and carters equally to all the website visitors, you need to ensure that the layout of the website looks the same across multiple browsers. Different web browsers render web pages in different ways. And that is why your website can look something on one and something different on another. Though the layout is not completely revamped, the placements of certain elements can be altered.
CSS is an amazing tool. But that doesn't mean you go paint the town with it. Use CSS only when and where it is the best solution available. Using it in places where you could have used another light feature would only hamper your website performance.
Though it is easy to use and great for testing it doesn't work well in the production code. Always keep the HTML and CSS separate.
Using too many CSS files make it very complex for any changes to be done to the layout. The processing time for files are significantly increased because the browser makes special request for every one of the files.