1. CSS should be placed above the structure (usually placed within the head element). CSS is an interpreted language, and Firefox and IE won't render anything until they wait for the CSS transfer to complete. Only by prepending CSS can the page be rendered when the browser parses the structure.
Example Source Code:
This causes the blank white screen problem. The page is totally blank until the stylesheet at the bottom is downloaded, on the order of 6-10 seconds for this page. The browser is waiting for the stylesheet to be loaded before it renders anything else in the page, even the static text.
The resulting problem is that the page will be "simple" for a while, and suddenly "gorgeous" again, resulting in a very poor user experience.
2. Try to use the <link rel="stylesheet" href="http://www.cnwebshow.com/123.css" type="text/css"> style import method, and reduce the use of @import, let alone Use multiple levels of nested @import. Because in IE, @import is equivalent to placing <link> at the end of the page.
Example Source Code
This is a valid syntax, but, even though it's in the document's HEAD, it breaks progressive rendering and instead causes the blank white screen and Flash of Unstyled